Archive for 'Antioxidants'

(Alpha lipoic acid–ALA)กรดแอลฟาไลโปอิค

Posted on 22. Dec, 2011 by .

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กรดแอลฟาไลโปอิค (Alpha lipoic acid–ALA) เรียกสั้นๆว่ากรดไลโปอิก หรือกรดไทออกติก (Thioctic acid), เมต้าวิตามิน (meta vitamin) เป็นกรดไขมัน ต้านอนุมูลอิสระ ที่ร่างกายสร้างได้เองตามธรรมชาติ แต่เมื่ออายุมากขึ้นหรือภาวะอ่อนแอ ทำให้การสร้างลดลง

ALA พบในสิ่งมีชีวิตทุกชนิด มีปริมาณเล็กน้อย สามารถกำจัดอนุมูลอิสระได้สูง และช่วยซ่อมสร้างวิตามินซี และอี ตลอดจนโปรตีนที่ถูกอ็อกซิไดส์ได้ด้วย

มีคุณสมบัติพิเศษคือ ละลายได้ทั้งในน้ำ และน้ำมัน จึงสามารถดูดซึม แทรกซึมเข้าสู่เซลล์ทั่วร่างกาย ตลอดจนผ่านแนวกั้นในสมอง (blood brain barrier) ได้ดี ทำให้ร่างกายนำไปใช้ประโยชน์ได้เต็มที่

แหล่งที่พบ

พบ ALA ได้ในมันฝรั่ง เนื้อแดง เครื่องใน ยีสต์ ผักโขม บล็อกโคลี่ ผักปวยเล้ง และอาหารประเภทเนื้อวัวไม่ติดมันหรืออวัยวะต่าง ๆ เช่น ตับ, หัวใจ และไต แต่อาจไม่เพียงพอเพื่อผลการรักษา บางคนจึงต้องใช้เสริมจากภายนอกในการบำบัดโรคต่างๆ

คุณสมบัติและการนำมาใช้ประโยชน์

1 กรดอัลฟาไลโปอิก เป็นสารอาหารประเภทหนึ่ง ที่มีลักษณะคล้ายวิตามิน โดยทำหน้าที่เป็น Coenzyme ในขบวนการเผาผลาญน้ำตาล และสารอาหารอื่น ๆ ให้เป็นพลังงาน โดยปกติ ร่างกายเราสามารถสังเคราะห์ กรดอัลฟาไลโปอิคได้เองอยู่แล้ว ในปริมาณคงที่ ซึ่งร่างกายเราผลิตได้ในจำนวนที่เพียงพอ ต่อการช่วย ไมโตคอนเดรีย (mitochondria) เปลี่ยนกลูโคสไปเป็นพลังงานเท่านั้น ไม่ได้ผลิตให้เหลือพอ ที่จะใช้ต่อต้านความเสื่อมชราของเซลล์ หรือเพิ่มภูมิคุ้มกันโรคให้กับร่างกาย

2 ALA มีขนาดโมเลกุลและภาวะแขนคู่ ที่เคลื่อนตัวได้คล่อง และพร้อมให้อิเลคตรอนได้ง่าย ทำให้ละลายได้ทั้งในน้ำและน้ำมัน มีประสิทธิภาพในการต้านอนุมูลอิสระสูง อีกทั้งช่วยส่งเสริม หรือซ่อมสารต้านอนุมูลอิสระตัวอื่น เช่น วิตามินซี วิตามินอี กูลตาไธโอน โคคิวเทน ให้กลับมาใช้งานซ้ำได้ หรือเป็นสารทดแทนกรณีสารต้านอนุมูลอิสระใดขาดแคลนไป มีบทบาทได้ทั้งภายในเซลล์ และที่เยื่อหุ้มเซลล์ ALA เป็นสารต้านออกซิเดชั่นที่ทรงพลัง ในการต่อสู้กับอนุมูลอิสระ ที่ปรากฏอยู่ใน ไมโตคอนเดรีย (mitochondria) ภายในเซลล์ นักวิทยาศาสตร์บางคนเชื่อว่า อนุมูลอิสระภายใน ไมโตคอนเดรีย (mitochondria) มีบทบาทสำคัญในการทำให้คนแก่ตัวลง จึงตั้งทฤษฎีว่า ถ้าให้สารยับยั้งออกซิเดชั่น อย่างกรดไลโปอิค ก็น่าชะลอความแก่ได้ กรด ไลโปอิคยังช่วยรีไซเคิลวิตามินอี และ วิตามิน ซี ให้กลับเป็นรูปเดิม หลังจากวิตามินอี และ วิตามินซี ไปล้างพิษอนุมูลอิสระเรียบร้อยแล้ว

3 ALA ทำงานส่งเสริมอินซูลิน ในการช่วยกวาดเก็บ นำมาใช้ และเก็บกักน้ำตาลในเลือด มีการศึกษาที่แสดงว่า oxidative stress มีผลในการเกิดอาการดื้อต่ออินซูลิน ที่เซลล์กล้ามเนื้อ แต่เมื่อเซลล์ได้รับ ALA จะได้รับการปกป้องจากอนุมูลอิสระได้ ALA ช่วยให้ผู้ป่วยเบาหวานตอบสนองต่ออินซูลิน เพิ่มประสิทธิภาพของอินซูลิน ต่อน้ำตาลในเลือด ทำให้ใช้บำบัดผู้ป่วยที่เป็นเบาหวาน

4 Diabetic neuropathy ประสาทถูกทำลายเนื่องจากเบาหวาน จากน้ำตาลในเลือดสูง หรือ oxidation ต่อเส้นประสาทนั้น วิตามิน B12 ช่วยไม่ได้มาก แต่ALA ใช้ได้ผลดีจากการที่ ALA มีส่วนร่วมในเมตาโบลิซึมของพลังงาน ช่วยการไหลเวียนเลือดตามหลอดเล็กๆ (เช่น เส้นที่ไปเลี้ยงเส้นประสาท) ดีขึ้น แล้วยังช่วยให้การใช้น้ำตาลในเลือดดีขึ้นด้วย ซึ่งคุณสมบัติเหล่านี้ นอกจาก ALA แล้ว ก็ยังมีวิตามินอี และ Capsaicin ที่ได้จากพริก

5 ต่อต้านการอักเสบอันเป็นเหตุให้เกิดสิว ช่วยรักษาการอักเสบไม่ให้สิวนั้นอักเสบลุกลามมากไป ALA มีฤทธิ์ทำความสะอาดและทำให้ผิวบริสุทธิ์ โดยการกำจัดของเสียออกจากร่างกาย ดังนั้นจึงสามารถป้องกันการเกิดสิว และยังช่วยเพิ่มประสิทธิภาพในการไหลเวียนของเลือดไปยังประสาท ดังนั้นผิวก็จะได้รับสารอาหารที่จำเป็นในการบำรุง ช่วยให้ผิวพรรณดูสดใสขึ้น กรดอัลฟ่าไลโปอิคช่วยต้านการอักเสบระดับปานกลาง เนื่องจากมีปริมาณของ Sulfur เป็น องค์ประกอบด้วย จึงช่วยลดการบวมและอาการผิวแดงจากสิว กรดอัลฟ่าไลโปอิคนั้นถือเป็นสารต้านอนุมูลอิสระที่ดีมากตัวหนึ่ง เนื่องจากสามารถละลายได้ทั้งในน้ำและน้ำมัน ด้วยเหตุนี้ร่างกายจึงสามารถดูดซึมได้ง่ายและสามารถเลี้ยงไปทั่วร่างกาย

ุ6 ALA ใช้รักษาอาการปวดและชาตามนิ้วมือนิ้วเท้า จากระบบประสาทถูกทำลาย ซึ่งอาจเกิดจากอนุมูลอิสระทำลายเซลล์ประสาท เมื่อระดับน้ำตาลในเลือดสูงผิดปกติ เกิดการเติมออกซิเจน (oxygenation) รวมทั้งอาการประสาทเสื่อมจากเบาหวาน ต้านการอักเสบ

7 ALA มีความสามารถจับตัวกับโลหะหนักที่เป็นพิษต่อร่างกาย เช่น ตะกั่ว แคดเมียม สารหนู ปรอท แล้วขับออกจากร่างกาย (Chelation) อีกทั้งคุณสมบัติที่ซึมผ่านแนวกั้นสมองได้ทำให้เชื่อว่าน่าจะมีบทบาทเข้าไป ช่วยนำโลหะหนักออกมาขับทิ้ง ผ่านตับ หรือไตได้

8 คุณสมบัติที่เพิ่มระดับกลูตาไธโอนในตับ ช่วยให้ตับขับล้างสารพิษตกค้าง ได้อย่างมีประสิทธิภาพ อีกทั้งช่วยบำรุงตับให้แข็งแรง

9 ALA ทำงานร่วมกับเอนไซม์ในร่างกาย เพื่อเร่งกระบวนการสร้างพลังงาน และจัดเป็นสารต้านอนุมูลอิสระฤทธิ์แรง ช่วยให้อนุภาคที่ไม่เสถียร และเป็นผลร้ายต่อร่างกาย มีสภาพเป็นกลาง ช่วยควบคุมระดับของธาตุเหล็ก และทองแดงซึ่งเป็นแร่ธาตุจำเป็นของร่างกายให้อยู่ในระดับที่พอดี

10 ALA ช่วยปกป้องตับมิให้ถูกอนุมูลอิสระทำลาย ช่วยกำจัดสารพิษออกจากร่างกาย มีการใช้สารนี้รักษาตับอักเสบ ตับแข็ง และโรคตับอื่นๆ รวมทั้งสารพิษตะกั่ว หรือโลหะหนักอื่นๆ และสารเคมีจาก อุตสาหกรรม เช่น carbon tetrachloride

11 ในสัตว์ทดลองยังพบประโยชน์ของ ALA ช่วยยับยั้งต้อกระจก เพิ่มความจำ และปกป้องเซลล์สมองจากการขาดเลือด
มีบางข้อมูลชี้ว่า ALA ยับยั้งการเพิ่มจำนวนของไวรัสจากคุณสมบัติต้านอนุมูลอิสระ เสริมภูมิคุ้มกัน และการทำงานของตับ ช่วยชะลอการเกิดหลอดเลือดแข็งตัว ซึ่งมักพบในผู้ป่วยเบาหวาน

12 การศึกษาผลของ ALA ในอัลไซเมอร์ และพาร์คินสัน บ่งชี้ว่า ALA น่าจะมีประโยชน์

13 ตลอดจนใช้คุณสมบัติต้านอนุมูลอิสระ ช่วยเรื่องอ่อนเพลียเรื้อรัง สะเก็ดเงิน ซึ่งรุนแรงจากอนุมูลอิสระ

14 พบว่า ALA ช่วยป้องกันการกระตุ้นอองโคยีน (oncogene) ซึ่งเป็นยีนควบคุมการเกิดมะเร็ง จากอนุมูลอิสระ และสารก่อมะเร็ง

15 อาการปวดแสบร้อนในปาก เหมือนกินพริก เข้าใจว่าอารมณ์แปรปรวนในวัยทอง การลดลงของฮอร์โมน หรือมีโรคของระบบประสาท หนึ่งในสามเกิดหลังทำฟัน การติดเชื้อยีสต์ (candida albicans) การขาดวิตามินบีต่างๆ และสังกะสี พบว่าการให้ ALA ชนิดออกฤทธิ์ช้าๆ ช่วยลดอาการได้ เข้าใจว่า ALA ไปทำลายอนุมูลอิสระที่กดดันประสาท และเพิ่มความเร็วของสัญญาณประสาท ALA เคยใช้กับการเจ็บปวดร้าวของประสาทไซอาติก (sciatic pain) ได้ผล จึงนำมาใช้กับอาการแสบร้อนในปาก
มีการทดลองให้ ALA เทียบกับยาหลอก พบว่า 97% มีอาการดีขึ้น, 74% ดีขึ้นอย่างเห็นได้ชัด, 13% หายขาด, 10% ดีขึ้นเพียงเล็กน้อย ในขณะที่กลุ่มยาหลอกมีอาการดีขึ้นเพียงเล็กน้อย 40% การติดตามผล 1 ปีให้หลัง พบว่ากลุ่มที่ได้ ALA 3 ใน 4 มีอาการดีขึ้นในระดับที่ดี ส่วนกลุ่มยาหลอกกลับมีอาการแย่ลง

16 มีงานวิจัยเกี่ยวกับการใช้ ALA เพิื่อการลดน้ำหนัก โดย ALA มีผลกับเอนไซม์ APK (activated protein kinase enzyme) ซึ่งพบในสมองส่วนไฮโปทาลามัส น่าจะมีหน้าที่สำคัญต่อความอยากอาหาร APK เพิ่มขึ้นเมื่อ เซลล์ต้องการพลังงานมากขึ้น ซึ่งอาจไปเพิ่มความอยากอาหาร

คนอ้วนส่วนมากไม่ตอบสนองต่อ Leptin ซึ่งนำมาใช้เป็นฮอร์โมนต่อต้านความอ้วน แต่ ALA พอที่จะให้ความหวังได้ โดยสัตว์ทดลองมีอัตราเผาผลาญสูงขึ้นด้วย กลูโคสและไขมันถูกเผาผลาญมากขึ้น

ในกรณีเบาหวาน ที่ดื้ออินซูลิน ย่อมดีขึ้น โดยลดการสะสมของไขมันที่กล้ามเนื้อ และเซลล์ไขมัน

ที่ไมโตคอนเดรีย เป็นตำแหน่งที่ ALA ทำงานในฐานะปัจจัยร่วม(Co factor)ในการย่อยกลูโคสและไขมัน

ALA เป็นตัวช่วยวิตามินทุกชนิด เช่น ไทอะมีน ไรโบฟลาวิน กรดแพนโธทีนิค และไนอาซิน ในการเปลี่ยนคาร์โบฮัยเดรท โปรตีน และไขมันจากอาหารให้กลายเป็นพลังงาน

ALA เป็นปัจจัยสำคัญใน internal cellular burn หรือการเผาผลาญภายในไมโตคอนเดรีย จึงช่วยเพิ่มอัตราเผาผลาญของเซลล์ เพิ่มพลังงาน และความสามารถในการซ่อมแซมของเซลล์

17 โรคประสาทที่ไม่ได้มาจากเบาหวาน ALA ก็น่าจะมีบทบาทจากการเป็นสารต้านอนุมูลอิสระตัวยง อีกทั้งไปเพิ่มระดับกลูตาไธโอนภายในเซลล์ ทำให้ช่วยซ่อมเซลล์ประสาทที่ถูกทำลายเสียหายให้ฟื้นกลับมาใหม่

การไม่เป็นพิษของ ALA จึงน่าจะผสมผสานเข้าไปเป็นส่วนหนึ่งของโปรแกรมโภชนาการ ร่วมกับวิตามินบีรวม แมกนีเซียม และกรดไขมันจำเป็น

ยังแนะนำให้ใช้ ALA ในโรค multiple sclerosis อาการพิษจากโลหะหนัก, ต้อกระจก และต้อหิน โรคตับจากพิษสุรา

ขนาดที่ใช้

ALA มักเป็นแคปซูล ขนาด 100 – 200 มก. แต่ขนาดที่ควรใช้คือ 600 – 800 มก. มีการศึกษาระบุว่าควรทาน 1800 มก.x 3 สำหรับกรณีที่รุนแรง
การใช้ปริมาณเล็กน้อย วันละ 20 – 150 มก. มักไม่มีผลข้างเคียงใดๆ

ขนาดที่ใช้แก้ปัญหาคือ 100 – 200 มก. X 3 ครั้ง / วัน ควรค่อยๆ เพิ่มจากน้อยไปหามาก การใช้ปริมาณมากในทันที อาจทำให้น้ำตาลในเลือดต่ำ เกิดอาการหน้ามืด เวียนศีรษะ ท้องไส้ปั่นป่วน หรือเกิดผื่นแดงตามผิวหนังได้บ้าง หากมีอาการก็ให้ลดขนาดหรือหยุดใช้ได้ แต่ก็น่าจะแสดงว่าร่างกายสนองต่อผลการรักษา

แพทย์ผู้รักษาที่เชี่ยวชาญอาจใช้ขนาดสูงได้ถึงวันละ 1800 มก.

ข้อพึงระวัง ยังไม่เคยมีการทดสอบในหญิงตั้งครรภ์หรือกำลังให้นมบุตร การใช้ปริมาณสูงจึงควรระวัง

อาจเสริมฤทธิ์ของกรด แกมมา–ไลโนเลนิค (GLA) และ / หรือ acetyl–L–carnitine ให้ผลดีมากยิ่งขึ้น ลดน้ำตาลในเลือดมากขึ้น ทำให้อาจต้องลดขนาดยาที่ใช้

อาจออกฤทธิ์ร่วมกับ T4 ไปชะลอการเปลี่ยนเป็น T3 จึงควรทานห่างกันหลายชั่วโมง

thank you and reference

1. รีดเดอร์สไดเจสท์ คู่มือฉลาดใช้วิตามินแร่ธาตุ และสมุนไพร ISBN 974-93003-51
3. วารสารอาหาร + สุขภาพ แปลโดย พอ.หญิงศรีนวล เจียจันทร์พงษ์ และคณะ ฉ.97/2545 115/2548, 127/2550
4. นิตยสารใกล้หมอ ก.พ. 2546
5 กินอยู่เพื่อสุขภาพ เล่ม 2
6 คัมภีร์สุขภาพ โดย อ.พนิดา
7 http://allageloc.blogspot.com/2010/11/alpha-lipoic-acid.html
8 http://www.mmc.co.th
9 http://acnethai.com
10

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Alpha Lipoic Acid

Posted on 07. Jun, 2011 by .

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Alpha lipoic acid (also known as lipoic acid, thioctic acid, or ALA) is a fatty acid found naturally inside every cell in the body. It’s needed by the body to produce the energy for our body’s normal functions. Alpha lipoic acid converts glucose (blood sugar) into energy.

Alpha lipoic acid is also an antioxidant, a substance that neutralizes potentially harmful chemicals called free radicals. Alpha-lipoic acid has been called a “universal antioxidant” because it is both water- and fat-soluble, and thus can penetrate tissues composed mainly of fat, such as the nervous system, as well as those made mainly of water, unlike the more common antioxidants vitamins C and E, and it appears to be able to recycle antioxidants such as vitamin C and glutathione after they have been used up. Glutathione is an important antioxidant that helps the body eliminate potentially harmful substances. Alpha lipoic acid increases the formation of glutathione.Many studies have been conducted confirming the health benefits of alpha-lipoic acid, including recent findings that ALA offers neuroprotective and possibly cognitive enhancing effects.

In the cells of the body, alpha-lipoic acid is converted into dihydrolipoic acid. Alpha-lipoic acid is not the same as alpha linolenic acid, which is an omega-3 fatty acid that may help heart health (See also: Alpha linolenic acid. Confusion can arise because both are sometimes abbreviated ALA.

Besides taking ALA for its general benefits as an antioxidant, studies have shown that alpha lipoic acid can help with the following conditions:

• Hypertension (High Blood Pressure)
• Coronary Heart Disease
• Metabolic Syndrome (high blood pressure and elevated cholesterol
• Peripheral Neuropathy (caused by diabetes and other conditions, such as Lyme
disease, alcoholism, shingles, thyroid disease and kidney failure)
• Diabetes (improving glucose metabolism and helping diabetics utilize insulin better)
• Liver Disease
• Metastatic Pancreatic Cancer (increasing long-term survival)
• Impaired Brain Function (as a treatment for stroke and other brain disorders
involving free radical damage, including Alzheimer’s disease)
• Effects of Aging (improving blood flow and enhancing immune function, restoring
levels of glutathione, a protective antioxidant and detoxification compound)
• Degenerative Diseases (ALA is a strong anti-inflammatory agent)
• Glaucoma and Cataracts

Hypertension (Elevated Blood Pressure); Coronary Heart Disease or Metabolic Syndrome (high blood pressure and elevated cholesterol): If you have hypertension or a build-up of plaque in your arteries from elevated cholesterol, you may benefit from alpha lipoic acid. The Boston University School of Medicine found that a combination of lipoic acid with another nutrient – acetyl-L-carnitine -helps lower blood pressure by increasing the width of arteries that had been constricted due to the build-up of plaque. Lipoic acid also improves the function of the mitochondria-a crucial part of the cell–involved in proper coronary vascular function.

Peripheral Neuropathy

: If you suffer from burning, pain, numbness or itching in your legs and feet caused by peripheral neuropathy, alpha lipoic acid may ease your symptoms. This condition can be caused by diabetes and other conditions, such as Lyme disease, alcoholism, shingles, thyroid disease and kidney failure. Certain injuries can also cause the above symptoms, as well as nutritional deficiencies and chemotherapy.

In 2003, researchers at the Mayo Clinic discovered that patients with diabetic neuropathy who received high doses of intravenous alpha lipoic acid had a threefold improvement in pain, numbness and other symptoms, compared with those treated with a placebo. Lipoic acid also seemed to increase blood flow and oxygen to the nerves, actually improving their condition. Used in Europe for over 30 years in treating diabetes, lipoic acid may also help cells better metabolize glucose. Many more studies are now being conducted in the U.S. and around the world to determine the role of ALA in helping diabetics utilize insulin.

Liver Disease

: Alpha lipoic acid was first used in the 1970s as a treatment for various forms of hepatitis by Burton M. Berkson, MD, MS, PhD, from the National Institutes of Health. The researchers administered alpha lipoic intravenously to 79 people with acute and severe liver damage at medical centers across the United States, and 75 recovered full liver function. In 2006, Dr. Berkson also reported using lipoic acid to increase the long-term survival of a patient suffering from metastatic pancreatic cancer.

Before 1977, if you suffered from severe liver disease – often caused by ingesting a toxin (mushroom poisoning, for example) – your only hope for recovery was a liver transplant. But in 1977, Dr. Berkson administered alpha lipoic acid intravenously to a patient dying from liver disease. The patient surprised doctors and not only recovered, but was free of liver disease 30 years later.

Brain Function and Stroke

Able to pass easily through the brain, alpha lipoic acid helps protect the brain and nerve tissue. It is currently being investigated as a treatment for stroke and other brain disorders involving free radical damage, including Alzheimer’s disease. Preliminary research shows that animals treated with lipoic acid suffered less brain damage and had four-times greater survival rate after a stroke than animals who didn’t receive this supplement. More research is needed to understand whether this benefit applies to people as well.

Anti-Aging Compound:

In May, 2007, Science Daily reported that alpha lipoic acid seemed to slow down the process of aging in animals by improving blood flow and enhancing immune function, as well as positively affecting several other factors involved in aging. Research findings were presented at Oregon State University (OSU) in a conference on Diet and Optimum Health. “The evidence suggests that lipoic acid is actually a low-level stressor that turns on the basic cellular defenses of the body, including some of those that naturally decline with age,” said Tory Hagen, an LPI researcher and associate professor of biochemistry and biophysics at OSU. “In particular, it tends to restore levels of glutathione, a protective antioxidant and detoxification compound, to those of a young animal. It also acts as a strong anti-inflammatory agent, which is relevant to many degenerative diseases.”

Eye Benefits

Free radicals are a major cause of cataract formation, according to Marc Grossman, O.D. Because high glucose levels also increase cataract formation, diabetics have three to four times the risk of developing cataracts over people without diabetes, Grossman states. Alpha-lipoic acid may help lower glucose levels by increasing insulin sensitivity. A Russian study published in the October-December 1995 issue of “Vestnik Oftamologii” reported that 45 percent to 47 percent of people in groups treated with lipoic acid showed improvement. Researchers attributed the improvement to antioxidant properties of LA and its influence on ocular metabolism

Disadvantages

Alpha-lipoic acid is eliminated rapidly from cells, according to the Linus Pauling Institute, so its benefits may not be sustained. Since LA may lower glucose levels, people with diabetes who take anti-diabetic drugs could experience hypoglycemia, or low blood sugar, when taking LA. Allergic reactions such as rash, hives and itching may also occur when taking supplements. Do not take LA without discussing its use with your doctor. Safe use in pregnancy has not been established.
Considerations

Some of the leading causes of blindness, such as cataracts and macular degeneration, are associated with cellular damage from free radicals, researchers from the London School of Hygiene and Tropical Medicine reported in the September 2010 issue of “Ophthalmic Research.” For diabetics, reducing blood glucose levels helps prevent diabetic retinopathy, another leading cause of blindness. Supplemental LA may not only reduce damage to DNA in cells from free radicals, but may also improve blood glucose levels.

Diabetes

Alpha-lipoic acid can lower blood sugar levels, and its ability to kill free radicals may help reduce pain, burning, itching, tingling, and numbness in people who have nerve damage caused by diabetes (called peripheral neuropathy). Alpha-lipoic acid has been used for years for this purpose in Europe, and at least one study found that intravenous (IV) doses of alpha-lipoic acid helped reduce symptoms. However, the evidence indicating that taking alpha-lipoic acid orally will help is weaker. Most studies have been small and poorly designed. One 2006 study did show benefit from taking alpha-lipoic acid for diabetic neuropathy compared to placebo.

Taking alpha-lipoic acid does appear to help another diabetes-related condition called autonomic neuropathy, which affects the nerves supplying the heart. One study found that 73 people with autonomic neuropathy improved when taking 800 mg of alpha-lipoic acid orally compared to placebo.

Other

Some preliminary studies suggest alpha-lipoic acid may be helpful in treating glaucoma, but there is not enough evidence to say for sure whether it is beneficial. In test tubes, alpha-lipoic acid appears to inhibit growth of the HIV virus, but it isn’t known whether the supplement would have the same effect in people.
Dietary Sources:

A healthy body makes enough alpha-lipoic acid. It is also found in red meat, organ meats (such as liver), and yeast (particularly Brewer’s yeast).
Available Forms:

Alpha-lipoic acid supplements are available as capsules. It may also be given by injection under the supervision of a health care provider.
How to Take It:

Pediatric

Because alpha-lipoic acid has not been studied for pediatric use, do not give it to children.

Adult

Alpha-lipoic acid can be purchased in doses of 30 – 100 mg tablets. There are no established recommended doses.

* General antioxidant support: 20 – 50 mg per day
* Diabetes and diabetic neuropathy: 800 mg per day in divided doses

Precautions:

Because of the potential for side effects and interactions with medications, you should take dietary supplements only under the supervision of a health care provider.

No evidence suggests whether or not alpha-lipoic acid is safe for women who are pregnant or breastfeeding, so such women should not take alpha-lipoic acid.

Foods High in Alpha Lipoic Acid

  • Some foods that are good sources of alpha lipoic acid include broccoli, beef, spinach, yeast, and various organic meats, like heart and kidney.

Side effects are generally rare and may include skin rash.

Alpha-lipoic acid can lower blood sugar levels, so people with diabetes or hypoglycemia should take alpha-lipoic acid only under the supervision of their doctor. (See “Interactions” section.)

Results of animal studies suggest that people who are deficient in thiamine (vitamin B1), a condition often associated with alcoholism, should not take alpha-lipoic acid.
Possible Interactions:

If you are currently being treated with any of the following medications, you should not use alpha-lipoic acid without first talking to your health care provider.

Insulin and drugs that lower blood sugar — Apha-lipoic acid can combine with these drugs to further reduce blood sugar levels, resulting in hypoglycemia (low blood sugar). Tell your doctor before taking alpha-lipoic acid and monitor your blood sugar levels closely; your doctor may need to adjust your medication doses.

Thyroid-regulating medications, Levothyroxine — Apha-lipoic acid may lower levels of thyroid hormone. Blood hormone levels and thyroid function tests should be monitored closely in people taking thyroid hormones who are also taking alpha-lipoic acid.
Alternative Names:

Dihydrolipoic acid; Lipoic acid; Lipolate; Thiotic acid

thank you and references

http://altmedicine.about.com/od/alphalipoicacid/a/alphalipoicacid.htm

http://www.umm.edu/altmed/articles/alpha-lipoic-000285.htm

http://www.alphalipoicacid.com

http://www.vitaminstuff.com/alpha-lipoic-acid.html

http://www.ehow.com/about_4760004_alpha-lipoic-acid-benefits.html

http://www.livestrong.com/article/426842-alpha-lipoic-acids-benefits-for-eyes/

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lutein

Posted on 17. Jan, 2011 by .

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Lutein is an antioxidant, which belongs to the carotenoid family. Lutein is a yellow coloured pigment. Although lutein is not categorized as a vitamin, dietary lutein is believed to be an essential nutrient for normal vision. a group of naturally occurring fat-soluble pigments found in plants. Lutein is the principal carotenoid present in the macula. The macula is responsible for supporting the health of the eye’s photoreceptor cell layer, which is why carotenoid levels are so important.

Lutein is concentrated in the retinas of your eyes and is necessary for good vision. A diet rich in lutein may lower your risk of developing cataracts and macular degeneration.
Lutein may also help prevent or slow down atherosclerosis, the thickening of arteries, which is a major risk for cardiovascular disease

Distribution
Lutein is found in egg yolk and many plants and vegetables, including red peppers, mustard, broccoli, zucchini, corn, garden peas, spinach, leek, collard greens and kale. Carrots, squash and other orange and yellow fruits and vegetables are sources of lutein. Green leafy vegetables, also contain high amounts of luteinLutein is responsible for the colouring of many fruits and vegetables.

Health Benefits of Lutein
Lutein is an antioxidant which is believed to be an essential nutrient for normal vision. The protective role of lutein against eye damage is well document. Studies have also indicated that lutein improves heart health, protects our skin against UV damage, reduces diabetes induced oxidative stress, and possesses anti-inflammatory and anti-cancer properties.

Eye protection
The central part of the retina, called the macula,[At the back of the eye the macula is a tiny area about 5 mm in diameter, with the fovea at its centre. There are no blood vessels, but lots of cells full of photosensitive pigments that allow us to see detail in the centre of vision. As we get older, the cells with retinal pigment become less efficient, the membrane degenerates, some cells atrophy, waste products build up, and central vision is gradually lost. ] contains macular pigments in which lutein is concentrated. The yellow coloured pigments protect the retina from damage of the photo-oxidative affect of high-energy light. Lutein offers eye protection by lowering the risk of age related vision loss, which causes gradual loss of central vision. Age related vision loss or age related macular degeneration is caused by steady damage of the retina.

Lutein Research – Blinded Study with Visible Results
Lutein has been shown to be beneficial to long term visual health. Seventeen participants were randomized in a double-blind study involving dietary supplementation with Lutein (15 mg), alpha-tocopherol (100 mg), or placebo, three times a week for up to two years.1 Visual performance, acuity and glare sensitivity were measured as parameters of vision health. In all parameters measured, subjects that consumed the Lutein had significant improvements in vision health when compared to the other groups.

In another recent placebo-controlled study, Lutein resulted in a significant improvement in eye pigment and optical density when compared to the placebo.2 The Lutein groups also significantly improved their visual acuity when compared to placebo

Heart health
Lutein can also reduce the risk for artery diseases. Studies have shown that persons with the highest lutein intake showed the lowest artery wall thickening. Lutein also reduces the oxidation of LDL cholesterol thereby reducing the risk of artery clogging.

Skin protection
Lutein can also reduce the risk of skin cancer and sunburn. Under influence of sunlight, free radicals are formed inside the skin. These free radicals can damage the DNA of cells. Lutein can protect against the damaging effects of UV-B radiation.

Note: Many lutein supplements that claim to have 6 mg of lutein per capsule may use an herbal extract that has 5% lutein. For instance, common supplements of lutein 6 mg are derived from 120mg of 5% marigold extract. Our lutein supplement comes from a marigold extract that is more than 94 percent lutein, not 5 %.

thank you and references
http://nutrition.about.com/od/phytochemicals/p/Lutein.htm
http://www.phytochemicals.info/phytochemicals/lutein.php
http://www.medicine.ox.ac.uk/bandolier/band123/b123-2.html


eVitamins

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rutin

Posted on 16. Jan, 2011 by .

1

Rutin is a bioflavonoid which means that it is part of a class of water soluble compounds Pure rutin is yellow or yellow-green colored needle-shaped crystal. Rutin is a flavonol glycoside comprised of the quercetin and the disaccharide rutinose (rhamnose and glucose).Bioflavonoids are found in the rind of green citrus fruits and in rose hips and black currants.

Quercetin is a flavonoid with a wide range of biological activities. It mainly occurs in plants as glycosides, such as rutin (quercetin rutinoside) in tea. Quercetin and rutin are used in many countries as medications for blood vessel protection and are ingredients
of numerous multivitamin preparations and herbal remedies. Rutin is also called rutoside.

Rutin, along with the other flavonoids, are sometimes called “vitamin P”. This used to be a common term for these compounds because they seemed to mimic the beneficial aspects of vitamins; however, they are not actually vitamins

Food Sources
Rutin is found in buckwheat seed, fruits and fruit rinds, especially citrus fruits (orange, grapefruit, lemon, lime) and berries such as mulberry.

Benefits
Rutin inhibits platelet aggregation, making the blood thinner and improve circulation.
Has anti-inflammatory activity.
Rutin inhibits aldose reductase activity. Aldose reductase is an enzyme normally present in the eye and elsewhere in the body. It helps change glucose (sugar – glucose) into a sugar alcohol called sorbitol. Too much sorbitol trapped in eye and nerve cells can damage these cells, leading to retinopathy and neuropathy. Substances that prevent or slow the action of aldose reductase are being studied as a way to prevent or delay these complications of diabetes. Aldose reductase is the first enzyme in the sorbitol pathway. This pathway is responsible for the conversion of glucose to sorbitol, and of galactose to galactitol. Under conditions of hyperglycemia, sorbitol accumulation occurs. Aldose reductase inhibitors prevent the accumulation of intracellular sorbitol. Whether rutin can help reduce the rate of glaucoma is not clear.

Through the years, the benefits of rutin has increased in number as more and more uses of this bioflavonoid are discovered. Rutin has been seen to be
effective in treating hemorrhoids and is actually used widely for this purpose. It is also seen to be effective in treating poor blood circulation, varicose veins and skin bruising. In addition, rutin helps your body properly utilize vitamin C and maintain skin collagen, both of which are important for healthy skin. It also strengthens your capillaries and counters high blood pressure and vein insufficiency. You can also use rutin as an anti-inflammatory treatment and for managing venous edema. On top of these, rutin reportedly has antioxidant properties that protect your body from free radicals which are harmful to your healthy cells. Consequently, as an anti-oxidant, rutin helps fight against strokes, arteriosclerosis, senility and slows down the aging process. It also has possible anti-carcinogenic properties.

Rutin has been evaluated in the following conditions:
Inflammatory bowel disease, see natural ways to treat this medical condition
Rutin has been tested as a treatment for varicose veins
In tardive dyskenisia as a result of antipsychotic medication use

rutin and Contraception
Rutin is the active ingredient in Rue (Ruta graveolens) historically Rue has been used as tea to induce miscarriage by thousands of women in latin america. The leaves were also eaten daily in salads as a contraceptive to prevent pregnancy. And according to Susun Weed Rutin can be used as a form of contraception or emergency contraception.

I have no evidence at this time suggesting whether or not rutin is effective at preventing pregnancy other than what is written in Susun’s book.

Susun writes “Rutin – Occurring naturally in association with Vitamin c in many plant leaves, most notably Rue, buckwheat, and Elder, rutin can be used to prevent pregnancy. Take it as a tablet in doses of at least 500 mg daily for several days preceding and following ovulation, or take it after fertilizing intercourse and continue until the menstrual flow begins.”3

Uni Tiamat writes in her book, Herbal Abortion “Rutin is also known to have the power to prevent pregnancy. In large doses, rutin prolongs the action of the adrenal hormone adrenaline and decreases capillary permeability in the uterine tissues.14 Decreased capillary permeability in the uterine tissues causes the endometrium to become non-nutritive to the fertilized egg. The egg does not implant and abortion occurs.”

Although there is no proof that Rutin will prevent pregnancy, some women will take 500 mg once daily a few days before and few days after ovulation as a natural contraceptive.

Miscarriage Risk

Rutin is the primary active ingredient in rue, an herbal product traditionally used to stimulate abortion. In early pregnancy, large amounts of rutin can cause miscarriage by preventing the attachment of the placenta. Large doses may also act as emergency contraceptives by preventing the implanation of a blastocyst.

In Pregnancy
In pregnancy, Rutin can help with the effects of varicose veins and hemorrhoids. However, the supplement can cause miscarriage, and any amount taken while pregnant should be closely monitored by a doctor.

Breastfeeding
Not enough information is known about the effects of Rutin on breast milk, and women are advised to not take the supplement if breastfeeding.

Rutin is a bioflavinoid, its main function in the body is to help the body strengthen arteries and veins and harden bones and teeth. Some of you have contacted me questioning why Rutin a bioflavinoid can be used to prevent pregnancy, when vitamin c should be used without bioflavinoids. There are still many questions, and I don’t have an explanation other than there are different types of bioflavinoids. One of my sources that suggest vitamin c for terminating pregnancy states that it doesn’t matter if the vitamin c has bioflavinoids, while others say it should be pure ascorbic acid. And in my studies I have come across references to bioflavinoids having the ability to protect against miscarriage. I’ve only done a small amount of research on bioflavinoids and have found that there are several different kinds of bioflavinoids, so it may be that certain kinds have different effects.

Rutin Dosage
Researches have suggested the effectivity or rutin doses that range from 200 to 600 milligrams. As commercial supplements, however, rutin tablets and rutin capsules are usually sold in 500 mg doses. The amount of rutin you take depends largely on why you are taking the medication. However, a regular dose of 500 mg taken once or twice a day is seen to be safe and effective.

Side Effects of Rutin
Rutin side effects are rare, but a few people have reported having experienced dizziness, heart racing, headache, muscle stiffness, fatigue, diarrhea, and upset stomach after taking rutin. Allergic reactions may occur in a few individuals. Symptoms of allergic reactions are chest pains, skin rashes, swelling and breathing problems. Allergic reactions happen very rarely as well.

Cautions for Rutin:

A potential side effect of using rutin capsules in this manner may make one feel anxious or fearful due to its effect of keeping adrenaline in the bloodstream.
Rutin should not be combined with other herbs or vitamins for purposes of preventing or terminating pregnancy.

Rutin: Other Names

Other names for this supplements (Rutin) include:

* Flavonoid
* Bioflavonoid
* Citrus bioflavonoid

Read more at http://www.wrongdiagnosis.com/vitamin/rutin.htm?ktrack=kcplink
thank you and references
http://www.drugs.com/mtm/rutin.html
http://www.phytochemicals.info/phytochemicals/rutin.php
http://www.herbs2000.com/h_menu/rutin.htm
http://www.nutritional-supplements-health-guide.com/rutin-supplement.html
http://www.raysahelian.com/rutin.html
http://www.wrongdiagnosis.com/vitamin/rutin.htm
http://www.sisterzeus.com/ERC_Rutin.html
http://www.ehow.com/facts_5892152_effects-rutin-pregnancy.html
http://www.vitaminsdiary.com/nutrients/rutin.htm
http://www.associatedcontent.com/article/5475358/rutin_and_pregnancy_safety_considerations.html

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Methionine

Posted on 11. Jan, 2011 by .

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Methionine is a sulfur containing essential amino acid and was first isolated in 1922 from casein .As one of the compounds known as a lipotrophic, a fat burner or antioxidant the others in this group include choline, inositol, and betaine. It is important in the process of methylation where methyl is added to compounds as well as being a precursor to the amino acids cystine and cysteine.

Amino acids are essential to human metabolism, and to making the human body function properly for good health. The human body, minus water, is 75 percent amino acids. All of the neurotransmitters, save one, are composed of amino acids and 95 percent of hormones are amino acids.the nutrient methionine is important for many bodily functions, including immune cell production and proper nerve function

Methionine (ME (TH) + THION + INE) is an essential amino acid, defined as one that can be obtained only through food. Methionine is the body’s primary source of sulfur. The body uses sulfur to influence hair follicles and promote healthy hair, skin, and nail growth. Sulfur increases the production of lecithin in the liver, which reduces cholesterol, reduces liver fat, protects the kidneys, reduces bladder irritation by regulating the formation of ammonia in the urine, and helps the body to excrete heavy metals.

Methionine is used to treat acetaminophen poisoning to prevent liver damage. It can be given orally or intravenously. Preparations containing both methionine and acetaminophen have been formulated for use in situations where overdose could occur.

Low levels of methionine in pregnant women have shown to increase the risk of neural tube defects (NTDs) in the fetus. These defects are caused by the failure of the neural tube to close properly during the formation of the central nervous system in the developing embryo. Mothers who have an adequate intake of methionine during the period from three months prior to conception through the first trimester of pregnancy significantly lower their risk of having a baby with a neural tube defect.

Substances, such as histamine, which can cause allergic reactions and dilate blood vessels can affect the way the brain sends and receives messages. Methionine works to reduce histamine levels in the body to allow proper synaptic function. Deficiencies in methionine levels can lead to severe mental disorders such as dementia, and in supplement form it is often prescribed for the treatment of schizophrenia. It has also been shown as a promising agent to assist with memory recall and the treatment of other mental disorders such as Parkinson’s and Alzheimer’s Disease, and for patients suffering from HIV/AIDS, attention deficit hyperactivity disorder (ADHD) in adults, fibromyalgia, and stress and anxiety.

Since 2002, cancer researchers have been studying the role of methionine in a special diet for patients diagnosed with colon cancer.

Methionine is also used by the body to manufacture SAMe, also known as S-adenosyl-methionine or S-adenosyl-L-methionine. SAMe is found in every cell in the body. SAMe has been shown to be effective as a treatment for osteoarthritis and associated joint pain, stiffness, and inflammation.

SAMe has been shown to be beneficial for most types of depression. Many studies have shown SAMe to be as effective as other antidepressant drugs, working more quickly with fewer side effects. In Europe, SAMe is prescribed more often than any other type of antidepressant.

SAMe improves and normalizes liver function. In Europe, SAMe is used in the treatment of cirrhosis and liver damage caused by alcohol.

SAMe has been shown to be effective in the treatment of fibromyalgia, AIDS-related myelopathy, and attention deficit-hyperactivity disorder (ADHD) in adults.

SAMe also assists the body in producing a wide range of compounds, including neurotransmitters such as serotonin and dopamine, as well as cartilage components such as glycosaminoglycans.

SAMe is manufactured within the body and is found in almost every tissue, but it can also be made synthetically.

Methionine can be found in meat, as well as fish, eggs, and dairy products. For vegetarians, grains and soya beans are a good source, but beans belonging to the legumes are not. Natural and synthetic methionine is also available in supplements, as well as those containing SAMe, in either capsule, tablet or powder form.

Requirements of methionine vary according to a person’s body weight, but most average-size adults need approximately 800-1,000 mg per day. Children need twice that amount, and infants require five times that amount.

Methionine supplements are often recommended by alternative medical practitioners, especially for those who are not getting a proper diet, such as vegetarians who might not be getting a balance of complete protein, athletes, people under severe stress, and anyone whose alcohol intake level is moderate to high.

Women who are pregnant or breastfeeding should talk to their doctors before using any kind of supplement. Women who are healthy and eat a well-balanced diet should not require methionine supplementation during pregnancy or while breastfeeding.

There are no known drug interactions associated with methionine, and although there appears to be no toxic dosage of this amino acid, it may cause side effects such as nausea, vomiting, drowsiness, and irritability.

Some common and significant side effects of methionine deficiency include liver damage, edema, weakness, and brittle hair. Low levels can slow normal growth and development in children. Insufficient levels in pregnant women may result in neural tube defects in infants, which are brain and spinal column disorders such as hydroencephaly or spina bifida

Groups at risk of methionine deficiency

People on low protein diets – people who are not eating enough protein foods may not get enough methionine in their diet
Vegans / vegetarian – people who are on a strict vegetarian diet may suffer from a methionine deficiency if their diet is deficient in protein
People in these groups at risk of methionine deficiency should talk to a medical professional about methionine supplements BEFORE taking them

Methionine works best with

Choline
Folic Acid
Inositol
Vitamin B1 (Thiamin)
Vitamin B2 (Riboflavin)
Vitamin B6 (Niacin)
Vitamin B12 (Cobalamin)
Iron
Magnesium
Cysteine
Cystine
Serine
Taurine

Side effects and cautions
The evidence gained from animal studies suggests that normal diets that are high in methionine content, especially when accompanied by deficiencies of the B vitamin complex, could possibly heighten the risk of atherosclerosis – which is the hardening of the arteries. This situation may come about due to an increase in the levels of cholesterol in the blood and higher levels of a compound called homocysteine in the body. Human tests conducted in the laboratory have not sufficiently tested out this hypothesis and further study is needed. The evidence however points to the fact that high methionine intake in the diet, if combined with deficiency in folic acid, vitamin B6 and vitamin B12 levels in the body, can lead to a great increase in the conversion of methionine to the compound called homocysteine. This compound is a chemical substance connected to heart disease and stroke in patients. The link between supplemental methionine and this relationship with deficiencies of the B vitamins has not been studied and whether or not this connection is a qualified hazard for humans using supplements of methionine must be established in further studies. No severe effects health wise has been registered in any patients who supplemented with up to two grams of methionine per day, even for long periods of time.

thank you and references
http://www.wisegeek.com/what-is-methionine.htm
http://www.anyvitamins.com/methionine-info.htm
http://www.dummies.com/how-to/content/methionine-amino-acid-support-for-your-liver.html
http://www.healthnews.com/natural-health/amino-acids/methionine-essential-sulfur-containing-amino-acid-643.html
http://www.herbs2000.com/amino_acids/methionine.htm

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vitamin E

Posted on 03. Dec, 2010 by .

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The term vitamin E describes a family of 8 antioxidants, 4 tocopherols and 4 tocotrienols. alpha-tocopherol (a-tocopherol) is the only form of vitamin E that is actively maintained in the human body and is therefore, the form of vitamin E found in the largest quantities in the blood and tissue.

Vitamin E is found naturally in some foods, added to others, and available as a dietary supplement. “Vitamin E” is the collective name for a group of fat-soluble compounds with distinctive antioxidant activities

Serum concentrations of vitamin E (alpha-tocopherol) depend on the liver, which takes up the nutrient after the various forms are absorbed from the small intestine. The liver preferentially resecretes only alpha-tocopherol via the hepatic alpha-tocopherol transfer protein; the liver metabolizes and excretes the other vitamin E forms . As a result, blood and cellular concentrations of other forms of vitamin E are lower than those of alpha-tocopherol and have been the subjects of less research

Antioxidants protect cells from the damaging effects of free radicals, which are molecules that contain an unshared electron. Free radicals damage cells and might contribute to the development of cardiovascular disease and cancer . Unshared electrons are highly energetic and react rapidly with oxygen to form reactive oxygen species (ROS). The body forms ROS endogenously when it converts food to energy, and antioxidants might protect cells from the damaging effects of ROS. The body is also exposed to free radicals from environmental exposures, such as cigarette smoke, air pollution, and ultraviolet radiation from the sun. ROS are part of signaling mechanisms among cells.

Vitamin E is a fat-soluble antioxidant that stops the production of ROS formed when fat undergoes oxidation. Scientists are investigating whether, by limiting free-radical production and possibly through other mechanisms, vitamin E might help prevent or delay the chronic diseases associated with free radicals.

In addition to its activities as an antioxidant, vitamin E is involved in immune function and, as shown primarily by in vitro studies of cells, cell signaling, regulation of gene expression, and other metabolic processes . Alpha-tocopherol inhibits the activity of protein kinase C, an enzyme involved in cell proliferation and differentiation in smooth muscle cells, platelets, and monocytes . Vitamin-E–replete endothelial cells lining the interior surface of blood vessels are better able to resist blood-cell components adhering to this surface. Vitamin E also increases the expression of two enzymes that suppress arachidonic acid metabolism, thereby increasing the release of prostacyclin from the endothelium, which, in turn, dilates blood vessels and inhibits platelet aggregation

Recommended Intakes

Intake recommendations for vitamin E and other nutrients are provided in the Dietary Reference Intakes (DRIs) developed by the Food and Nutrition Board (FNB) at the Institute of Medicine of The National Academies (formerly National Academy of Sciences). DRI is the general term for a set of reference values used to plan and assess nutrient intakes of healthy people. These values, which vary by age and gender, include:

* Recommended Dietary Allowance (RDA): average daily level of intake sufficient to meet the nutrient requirements of nearly all (97%-98%) healthy people.

* Adequate Intake (AI): established when evidence is insufficient to develop an RDA and is set at a level assumed to ensure nutritional adequacy.

* Tolerable Upper Intake Level (UL): maximum daily intake unlikely to cause adverse health effects “.

The FNB’s vitamin E recommendations are for alpha-tocopherol alone, the only form maintained in plasma. The FNB based these recommendations primarily on serum levels of the nutrient that provide adequate protection in a test measuring the survival of erythrocytes when exposed to hydrogen peroxide, a free radical . Acknowledging “great uncertainties” in these data, the FNB has called for research to identify other biomarkers for assessing vitamin E requirements.

RDAs for vitamin E are provided in milligrams (mg) and are listed in Table 1. Because insufficient data are available to develop RDAs for infants, AIs were developed based on the amount of vitamin E consumed by healthy breastfed babies.

At present, the vitamin E content of foods and dietary supplements is listed on labels in international units (IUs), a measure of biological activity rather than quantity. Naturally sourced vitamin E is called d-alpha-tocopherol; the synthetically produced form is dl-alpha-tocopherol. Conversion rules are as follows:

* To convert from mg to IU: 1 mg of alpha-tocopherol is equivalent to 1.49 IU of the natural form or 2.22 IU of the synthetic form.

* To convert from IU to mg: 1 IU of alpha-tocopherol is equivalent to 0.67 mg of the natural form or 0.45 mg of the synthetic form.

Table 1 lists the RDAs for alpha-tocopherol in both mg and IU of the natural form; for example, 15 mg x 1.49 IU/mg = 22.4 IU. The corresponding value for synthetic alpha-tocopherol would be 33.3 IU (15 mg x 2.22 IU/mg).

Sources of Vitamin E

Food

Numerous foods provide vitamin E. Nuts, seeds, and vegetable oils are among the best sources of alpha-tocopherol, and significant amounts are available in green leafy vegetables and fortified cereals (see Table 2 for a more detailed list).Most vitamin E in American diets is in the form of gamma-tocopherol from soybean, canola, corn, and other vegetable oils and food products

Dietary supplements

Supplements of vitamin E typically provide only alpha-tocopherol, although “mixed” products containing other tocopherols and even tocotrienols are available. Naturally occurring alpha-tocopherol exists in one stereoisomeric form. In contrast, synthetically produced alpha-tocopherol contains equal amounts of its eight possible stereoisomers; serum and tissues maintain only four of these stereoisomers . A given amount of synthetic alpha-tocopherol (listed on labels as “DL” or “dl”) is therefore only half as active as the same amount (by weight in mg) of the natural form (labeled as “D” or “d”). People need approximately 50% more IU of synthetic alpha tocopherol from dietary supplements and fortified foods to obtain the same amount of the nutrient as from the natural form.

Most vitamin-E-only supplements provide ≥100 IU of the nutrient. These amounts are substantially higher than the RDAs. The 1999-2000 National Health and Nutrition Examination Survey (NHANES) found that 11.3% of adults took vitamin E supplements containing at least 400 IU.

Alpha-tocopherol in dietary supplements and fortified foods is often esterified to prolong its shelf life while protecting its antioxidant properties. The body hydrolyzes and absorbs these esters (alpha-tocopheryl acetate and succinate) as efficiently as alpha-tocopherol .

Vitamin E Intakes and Status

Three national surveys—the 2001-2002 NHANES , NHANES III (1988-1994) , and the Continuing Survey of Food Intakes by Individuals (1994-1996)—have found that the diets of most Americans provide less than the RDA levels of vitamin E. These intake estimates might be low, however, because the amounts and types of fat added during cooking are often unknown and not accounted for .

The FNB suggests that mean intakes of vitamin E among healthy adults are probably higher than the RDA but cautions that low-fat diets might provide insufficient amounts unless people make their food choices carefully by, for example, increasing their intakes of nuts, seeds, fruits, and vegetables .

Vitamin E Deficiency

Frank vitamin E deficiency is rare and overt deficiency symptoms have not been found in healthy people who obtain little vitamin E from their diets. Premature babies of very low birth weight (<1,500 grams) might be deficient in vitamin E. Vitamin E supplementation in these infants might reduce the risk of some complications, such as those affecting the retina, but they can also increase the risk of infections.

Because the digestive tract requires fat to absorb vitamin E, people with fat-malabsorption disorders are more likely to become deficient than people without such disorders. Deficiency symptoms include peripheral neuropathy, ataxia, skeletal myopathy, retinopathy, and impairment of the immune response . People with Crohn’s disease, cystic fibrosis, or an inability to secrete bile from the liver into the digestive tract, for example, often pass greasy stools or have chronic diarrhea; as a result, they sometimes require water-soluble forms of vitamin E, such as tocopheryl polyethylene glycol-1000 succinate .

Some people with abetalipoproteinemia, a rare inherited disorder resulting in poor absorption of dietary fat, require enormous doses of supplemental vitamin E (approximately 100 mg/kg or 5-10 g/day). Vitamin E deficiency secondary to abetalipoproteinemia causes such problems as poor transmission of nerve impulses, muscle weakness, and retinal degeneration that leads to blindness . Ataxia and vitamin E deficiency (AVED) is another rare, inherited disorder in which the liver’s alpha-tocopherol transfer protein is defective or absent. People with AVED have such severe vitamin E deficiency that they develop nerve damage and lose the ability to walk unless they take large doses of supplemental vitamin E .

Vitamin E and Health

Many claims have been made about vitamin E’s potential to promote health and prevent and treat disease. The mechanisms by which vitamin E might provide this protection include its function as an antioxidant and its roles in anti-inflammatory processes, inhibition of platelet aggregation, and immune enhancement.

A primary barrier to characterizing the roles of vitamin E in health is the lack of validated biomarkers for vitamin E intake and status to help relate intakes to valid predictors of clinical outcomes . This section focuses on four diseases and disorders in which vitamin E might be involved: heart disease, cancer, eye disorders, and cognitive decline.

Coronary heart disease

Evidence that vitamin E could help prevent or delay coronary heart disease (CHD) comes from several sources. In vitro studies have found that the nutrient inhibits oxidation of low-density lipoprotein (LDL) cholesterol, thought to be a crucial initiating step for atherosclerosis . Vitamin E might also help prevent the formation of blood clots that could lead to a heart attack or venous thromboembolism .

Several observational studies have associated lower rates of heart disease with higher vitamin E intakes. One study of approximately 90,000 nurses found that the incidence of heart disease was 30% to 40% lower in those with the highest intakes of vitamin E, primarily from supplements . Among a group of 5,133 Finnish men and women followed for a mean of 14 years, higher vitamin E intakes from food were associated with decreased mortality from CHD .

However, randomized clinical trials cast doubt on the efficacy of vitamin E supplements to prevent CHD . For example, the Heart Outcomes Prevention Evaluation (HOPE) study, which followed almost 10,000 patients at high risk of heart attack or stroke for 4.5 years ,und that participants taking 400 IU/day of natural vitamin E experienced no fewer cardiovascular events or hospitalizations for heart failure or chest pain than participants taking a placebo. In the HOPE-TOO followup study, almost 4,000 of the original participants continued to take vitamin E or placebo for an additional 2.5 years .OPE-TOO found that vitamin E provided no significant protection against heart attacks, strokes, unstable angina, or deaths from cardiovascular disease or other causes after 7 years of treatment. Participants taking vitamin E, however, were 13% more likely to experience, and 21% more likely to be hospitalized for, heart failure, a statistically significant but unexpected finding not reported in other large studies.

The HOPE and HOPE-TOO trials provide compelling evidence that moderately high doses of vitamin E supplements do not reduce the risk of serious cardiovascular events among men and women >50 years of age with established heart disease or diabetes.hese findings are supported by evidence from the Women’s Angiographic Vitamin and Estrogen study, in which 423 postmenopausal women with some degree of coronary stenosis took supplements with 400 IU vitamin E (type not specified) and 500 mg vitamin C twice a day or placebo for >4 years [.Not only did the supplements provide no cardiovascular benefits, but all-cause mortality was significantly higher in the women taking the supplements.

The latest published clinical trial of vitamin E’s effects on the heart and blood vessels of women included almost 40,000 healthy women ≥45 years of age who were randomly assigned to receive either 600 IU of natural vitamin E on alternate days or placebo and who were followed for an average of 10 years .he investigators found no significant differences in rates of overall cardiovascular events (combined nonfatal heart attacks, strokes, and cardiovascular deaths) or all-cause mortality between the groups. However, the study did find two positive and significant results for women taking vitamin E: they had a 24% reduction in cardiovascular death rates, and those ≥65 years of age had a 26% decrease in nonfatal heart attack and a 49% decrease in cardiovascular death rates.

The most recent published clinical trial of vitamin E and men’s cardiovascular health included almost 15,000 healthy physicians ≥50 years of age who were randomly assigned to receive 400 IU synthetic alpha-tocopherol every other day, 500 mg vitamin C daily, both vitamins, or placebo.uring a mean followup period of 8 years, intake of vitamin E (and/or vitamin C) had no effect on the incidence of major cardiovascular events, myocardial infarction, stroke, or cardiovascular morality. Furthermore, use of vitamin E was associated with a significantly increased risk of hemorrhagic stroke.

In general, clinical trials have not provided evidence that routine use of vitamin E supplements prevents cardiovascular disease or reduces its morbidity and mortality. However, participants in these studies have been largely middle-aged or elderly individuals with demonstrated heart disease or risk factors for heart disease. Some researchers have suggested that understanding the potential utility of vitamin E in preventing CHD might require longer studies in younger participants taking higher doses of the supplement.urther research is needed to determine whether supplemental vitamin E has any protective value for younger, healthier people at no obvious risk of CHD.

Cancer

Antioxidant nutrients like vitamin E protect cell constituents from the damaging effects of free radicals that, if unchecked, might contribute to cancer development .itamin E might also block the formation of carcinogenic nitrosamines formed in the stomach from nitrites in foods and protect against cancer by enhancing immune function .Human trials and surveys that attempted to associate vitamin E intake with cancer incidence have generally been inconclusive.

Some research links higher intakes of vitamin E with a decreased incidence of breast and prostate cancers .ut the evidence is inconsistent. For example, an examination of the impact of dietary factors, including vitamin E, on the incidence of postmenopausal breast cancer in >18,000 women found no benefit from the vitamin .imilarly, a prospective cohort study of >29,000 men found no association between dietary or supplemental vitamin E intake and prostate cancer risk, with one exception: among current smokers and men who had quit, vitamin E intakes of more than 400 IU/day were associated with a statistically significant 71% reduction in the risk of advanced prostate cancer .A large randomized clinical trial began in 2001 to determine whether 7-12 years of daily supplementation with synthetic vitamin E (400 IU), with or without selenium (200 mcg), reduces the number of new prostate cancers in healthy men. The trial was discontinued in October 2008 when an analysis found that the supplements, taken alone or together for an average of 5 years, did not prevent prostate cancer .Study staff members will continue to monitor participants’ health for an additional 3 years.

One study of women in Iowa provides evidence that higher intakes of vitamin E from foods and supplements could decrease the risk of colon cancer, especially in women <65 years of .The overall relative risk for the highest quintile of intake (>35.7 IU/day) compared to the lowest quintile (<5.7 IU/day) was 0.32. However, prospective cohort studies of 87,998 women in the Nurses’ Health Study and 47,344 men in the Health Professionals Follow-up Study failed to replicate these results .

The American Cancer Society conducted an epidemiologic study examining the association between use of vitamin C and vitamin E supplements and bladder cancer mortality. Of the almost one million adults followed between 1982 and 1998, adults who took supplemental vitamin E for 10 years or longer had a reduced risk of death from bladder cancer .itamin C supplementation provided no protection.

Both the recently published HOPE-TOO Trial and Women’s Health Study evaluated whether vitamin E supplements might protect people from cancer. HOPE-TOO, which followed men and women ≥55 years of age with heart disease or diabetes for 7 years, found no significant differences in the number of new cancers or cancer deaths between the groups taking 400 IU/day vitamin E or a placebo .In the Women’s Health Study, in which healthy women ≥45 years of age received either 600 IU vitamin E every other day or a placebo for 10 years, the supplement did not reduce the risk of developing any form of cancer .

The inconsistent and limited evidence precludes any recommendations about using vitamin E supplements to prevent cancer.

Eye disorders

Age-related macular degeneration (AMD) and cataracts are among the most common causes of significant vision loss in older people. Their etiologies are usually unknown, but the cumulative effects of oxidative stress have been postulated to play a role. If so, nutrients with antioxidant functions, such as vitamin E, could be used to prevent or treat these conditions.

Prospective cohort studies have found that people with relatively high dietary intakes of vitamin E (e.g., 30 .However, two randomized controlled trials in which participants took supplements of vitamin E (500 IU/day d-alpha-tocopherol in one study .nd 111 IU/day dl-alpha-tocopheryl acetate combined with 20 mg/day beta-carotene in the other .or a placebo failed to show a protective effect for vitamin E on AMD. The Age-Related Eye Disease Study (AREDS), a large randomized clinical trial, revealed that participants with early-stage AMD could slow the progression of their disease by taking a daily supplement of vitamin E (400 IU dl-alpha-tocopheryl acetate), vitamin C (500 mg), beta-carotene (15 mg), zinc (80 mg), and copper (2 mg) for an average of 6.3 years compared to participants taking a placebo.

Several observational studies have revealed a potential relationship between vitamin E supplements and the risk of cataract formation. One prospective cohort study found that lens clarity was superior in participants who took vitamin E supplements and those with higher blood levels of the vitamin.In another study, long-term use of vitamin E supplements was associated with slower progression of age-related lens opacification .parent effect on the development or progression of cataracts over 7 years .

Overall, the available evidence is inconsistent with respect to whether vitamin E supplements, taken alone or in combination with other antioxidants, can reduce the risk of developing AMD or cataracts. However, the formulation of vitamin E, other antioxidants, zinc, and copper used in AREDS holds promise for slowing the progression of AMD in people with early-stage disease. Cognitive decline

The brain has a high oxygen consumption rate and abundant polyunsaturated fatty acids in the neuronal cell membranes. Researchers hypothesize that if cumulative free-radical damage to neurons over time contributes to cognitive decline and neurodegenerative diseases, such as Alzheimer’s disease, then ingestion of sufficient or supplemental antioxidants (such as vitamin E) might provide some protection.his hypothesis was supported by the results of a clinical trial in 341 patients with Alzheimer’s disease of moderate severity who were randomly assigned to receive a placebo, vitamin E (2,000 IU/day dl-alpha-tocopherol), a monoamine oxidase inhibitor (selegiline), or vitamin E and selegiline.Over 2 years, treatment with vitamin E and selegiline, separately or together, significantly delayed functional deterioration and the need for institutionalization compared to placebo. However, participants taking vitamin E experienced significantly more falls.

Vitamin E consumption from foods or supplements was associated with less cognitive decline over 3 years in a prospective cohort study of elderly, free-living individuals aged 65-102 years.owever, a clinical trial in primarily healthy older women who were randomly assigned to receive 600 IU d-alpha-tocopherol every other day or a placebo for ≤4 years found that the supplements provided no apparent cognitive benefits.nother trial in which 769 men and women with mild cognitive impairment were randomly assigned to receive 2,000 IU/day vitamin E (type not specified), a cholinesterase inhibitor (donepezil), or placebo found no significant differences in the progression rate of Alzheimer’s disease between the vitamin E and placebo groups.

In summary, most research results do not support the use of vitamin E supplements by healthy or mildly impaired individuals to maintain cognitive performance or slow its decline with normal aging .More research is needed to identify the role of vitamin E, if any, in the management of cognitive impairment .

Health Risks from Excessive Vitamin E

Research has not found any adverse effects from consuming vitamin E in food .owever, high doses of alpha-tocopherol supplements can cause hemorrhage and interrupt blood coagulation in animals, and in vitro data suggest that high doses inhibit platelet aggregation. Two clinical trials have found an increased risk of hemorrhagic stroke in participants taking alpha-tocopherol; one trial included Finnish male smokers who consumed 50 mg/day for an average of 6 years .he other trial involved a large group of male physicians in the United States who consumed 400 IU every other day for 8 years.ecause the majority of physicians in the latter study were also taking aspirin, this finding could indicate that vitamin E has a tendency to cause bleeding.

The FNB has established ULs for vitamin E based on the potential for hemorrhagic effects (see Table 3). The ULs apply to all forms of supplemental alpha-tocopherol, including the eight stereoisomers present in synthetic vitamin E. Doses of up to 1,000 mg/day (1,500 IU/day of the natural form or 1,100 IU/day of the synthetic form) in adults appear to be safe, although the data are limited and based on small groups of people taking at least 2,000 IU for a few weeks or months. Long-term intakes above the UL increase the risk of adverse health effects .itamin E ULs for infants have not been established.

Two meta-analyses of randomized trials have raised questions about the safety of large doses of vitamin E, including doses lower than the UL. These meta-analyses linked supplementation to small but statistically significant increases in all-cause mortality. One analysis found an increased risk of death at doses of ≥400 IU/day, although the risk began to increase at 150 IU .n the other analysis of studies of antioxidant supplements for disease prevention, the highest quality trials revealed that vitamin E, administered singly (dose range 10 IU-5,000 IU/day; mean 569 IU) or combined with up to four other antioxidants, significantly increased mortality risk.he implications of these analyses for the potential adverse effects of high-dose vitamin E supplements are unclear .articipants in the studies included in these analyses were typically middle-aged or older and had chronic diseases or related risk factors. These participants often consumed other supplements in addition to vitamin E. Some of the studies analyzed took place in developing countries in which nutritional deficiencies are common. A review of the subset of studies in which vitamin E supplements were given to healthy individuals for the primary prevention of chronic disease found no convincing evidence that the supplements increased mortality .

Interactions with Medications

Vitamin E supplements have the potential to interact with several types of medications. A few examples are provided below. People taking these and other medications on a regular basis should discuss their vitamin E intakes with their healthcare providers.

Anticoagulant and antiplatelet medications

Vitamin E can inhibit platelet aggregation and antagonize vitamin K-dependent clotting factors. As a result, taking large doses with anticoagulant or antiplatelet medications, such as warfarin (Coumadin®), can increase the risk of bleeding, especially in conjunction with low vitamin K intake. The amounts of supplemental vitamin E needed to produce clinically significant effects are unknown but probably exceed 400 IU/day .imvastatin and niacin

Some people take vitamin E supplements with other antioxidants, such as vitamin C, selenium, and beta-carotene. This collection of antioxidant ingredients blunted the rise in high-density lipoprotein (HDL) cholesterol levels, especially levels of HDL2, the most cardioprotective HDL component, among people treated with a combination of simvastatin (brand name Zocor®) and niacin .hemotherapy and radiotherapy

Oncologists generally advise against the use of antioxidant supplements during cancer chemotherapy or radiotherapy because they might reduce the effectiveness of these therapies by inhibiting cellular oxidative damage in cancerous cells . Although a systematic review of randomized controlled trials has called this concern into question .urther research is needed to evaluate the potential risks and benefits of concurrent antioxidant supplementation with conventional therapies for cancer.

Food Sources

Vitamin E is found in the following foods:

*

Wheat germ

*Corn
*Nuts
*Seeds
*Olives
*Spinach and other green leafy vegetables
*Asparagus
*Vegetable oils — corn, sunflower, soybean, cottonseed

Products made from these foods, such as margarine, also contain vitamin E.

Side Effects

In November, 2004, the American Heart Association stated that high amounts of vitamin E can be harmful. Taking 400 IU per day, or higher, may increase the risk of death.

Taking smaller amounts, such as those found in a typical multivitamin, was not harmful.

Recommendations

The Food and Nutrition Board at the Institute of Medicine report the following dietary reference intakes for vitamin E:

Infants

*0 to 6 months: 4 mg/day
*7 to 12 months: 5 mg/day

Children

*1 to 3 years: 6 mg/day
*4 to 8 years: 7 mg/day
*9 to 13 years: 11 mg/day

Adolescents and Adults

*14 and older: 15 mg/day

The best way to get the daily requirement of essential vitamins is to eat a balanced diet that contains a variety of foods from the food guide pyramid.

Specific recommendations depend on age, gender, and other factors (such as pregnancy). Women who are pregnant or producing breast milk (lactating) need higher amounts. Ask your health care provider which amount is best for you.

Alternative Names

Deficiency – vitamin E; Tocopherol

Vitamin E and the risk of Alzheimer’s disease.

Some evidence on the role of vitamin E in reducing the risk of Alzheimer’s was reported in 3 recent studies. The first study, conducted at the Rush Institute for Healthy Aging of the Rush-Presbyterian-St Luke’s Medical Center found that an increased vitamin E intake from foods was associated with a decreased risk of developing Alzheimer’s disease.

The second study, conducted in the Netherlands, showed that vitamin E from food, but not other antioxidants, may be associated with a decreased risk. The third study, which was conducted in Italy, evaluated a high dose of 2,000 IU and found a substantial protective effect. It appears that the effect of vitamin E from supplements is detectable only with high doses.

Vitamin E and Healthful Diets

According to the 2005 Dietary Guidelines for Americans, “nutrient needs should be met primarily through consuming foods. Foods provide an array of nutrients and other compounds that may have beneficial effects on health. In certain cases, fortified foods and dietary supplements may be useful sources of one or more nutrients that otherwise might be consumed in less than recommended amounts. However, dietary supplements, while recommended in some cases, cannot replace a healthful diet.”

The Dietary Guidelines for Americans describes a healthy diet as one that:

*

Emphasizes a variety of fruits, vegetables, whole grains, and fat-free or low-fat milk and milk products.

Vitamin E is found in green leafy vegetables, whole grains, and fortified cereals.

*Includes lean meats, poultry, fish, beans, eggs, and nuts.

Nuts are good sources of vitamin E.

*Is low in saturated fats, trans fats, cholesterol, salt (sodium), and added sugars.

Vitamin E is commonly found in vegetable oils.

*Stays within your daily calorie needs.

thank you and references

http://ods.od.nih.gov/factsheets/vitamine/

http://www.healingdaily.com/detoxification-diet/vitamin-e.htm

http://www.nlm.nih.gov/medlineplus/ency/article/002406.htm

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Antioxidants

Posted on 03. Dec, 2010 by .

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Antioxidants protect the body from damage caused by harmful molecules called free radicals. Many experts believe this damage is a factor in the development of blood vessel disease (atherosclerosis), cancer, and other conditions.

Antioxidants are substances that may protect your cells against the effects of free radicals. Free radicals are molecules produced when your body breaks down food, or by environmental exposures like tobacco smoke and radiation. Free radicals can damage cells, and may play a role in heart disease, cancer and other diseases.

You are exposed to free radicals:

Through by-products of normal processes that take place in your body (such as the burning of sugars for energy and the release of digestive enzymes to break down food).
When the body breaks down certain medicines.
Through pollutants.
Antioxidants include some vitamins (such as vitamins C and E), some minerals (such as selenium), and flavonoids, which are found in plants. The best sources of antioxidants are fruits and vegetables. You can find flavonoids in fruits, red wine, and teas. You can also buy antioxidant supplements.

One study showed that using vitamin A, E, and beta carotene supplements may increase your risk of premature death.1 Further study is needed to look at the effects of these antioxidants as well as vitamin C and selenium. It is best to obtain antioxidants from a healthy diet.

What are antioxidants used for?
People use antioxidants to help treat or prevent some medical conditions, such as coronary artery disease (CAD), some cancers, macular degeneration, Alzheimer’s disease, and some arthritis-related conditions.

The treatment of CAD with antioxidant supplements as well as with traditional medicine continues to be researched. Some experts believe antioxidant vitamins may help in treating CAD, although so far studies have not proved this.

Are antioxidants safe?
Until more studies are done, it is best to get your antioxidants from a diet rich in fruits and vegetables rather than from supplements. Taking supplements in high doses can be harmful. No single antioxidant alone can protect the body. Most people should eat 5 to 9 servings of fruits and vegetables each day.

The U.S. Food and Drug Administration (FDA) does not regulate dietary supplements in the same way it regulates medicines. A dietary supplement can be sold with limited or no research on how well it works.

Always tell your doctor if you are using a dietary supplement or if you are thinking about combining a dietary supplement with your conventional medical treatment. It may not be safe to forgo your conventional medical treatment and rely only on a dietary supplement. This is especially important for women who are pregnant or breast-feeding.

When using dietary supplements, keep in mind the following:

Like conventional medicines, dietary supplements may cause side effects, trigger allergic reactions, or interact with prescription and nonprescription medicines or other supplements you are taking. A side effect or interaction with another medicine or supplement may make your health worse.
How dietary supplements are manufactured may not be standardized. Because of this, how well they work or any side effects they cause may differ among brands or even within different lots of the same brand. The form of a supplement that you buy in health food or grocery stores may not be the same as the form used in research.
Other than for vitamins and minerals, the long-term effects of most dietary supplements are not known

Antioxidant substances include

Beta-carotene
Lutein
Lycopene
Selenium
Vitamin A
Vitamin C
Vitamin E
Antioxidants are found in many foods. These include fruits and vegetables, nuts, grains, and some meats, poultry and fish.

Can antioxidants prevent cancer?
Considerable laboratory evidence from chemical, cell culture, and animal studies indicates that antioxidants may slow or possibly prevent the development of cancer. However, information from recent clinical trials is less clear. In recent years, large-scale, randomized clinical trials reached inconsistent conclusions.

What was shown in previously published large-scale clinical trials?
Five large-scale clinical trials published in the 1990s reached differing conclusions about the effect of antioxidants on cancer. The studies examined the effect of beta-carotene and other antioxidants on cancer in different patient groups. However, beta-carotene appeared to have different effects depending upon the patient population. The conclusions of each study are summarized below.

The first large randomized trial on antioxidants and cancer risk was the Chinese Cancer Prevention Study, published in 1993. This trial investigated the effect of a combination of beta-carotene, vitamin E, and selenium on cancer in healthy Chinese men and women at high risk for gastric cancer. The study showed a combination of beta-carotene, vitamin E, and selenium significantly reduced incidence of both gastric cancer and cancer overall (1).

A 1994 cancer prevention study entitled the Alpha-Tocopherol (vitamin E)/ Beta-Carotene Cancer Prevention Study (ATBC) demonstrated that lung cancer rates of Finnish male smokers increased significantly with beta-carotene and were not affected by vitamin E (2).

Another 1994 study, the Beta-Carotene and Retinol (vitamin A) Efficacy Trial (CARET), also demonstrated a possible increase in lung cancer associated with antioxidants (3).

The 1996 Physicians’ Health Study I (PHS) found no change in cancer rates associated with beta-carotene and aspirin taken by U.S. male physicians (4).

The 1999 Women’s Health Study (WHS) tested effects of vitamin E and beta-carotene in the prevention of cancer and cardiovascular disease among women age 45 years or older. Among apparently healthy women, there was no benefit or harm from beta-carotene supplementation. Investigation of the effect of vitamin E is ongoing (5).

How might antioxidants prevent cancer?
Antioxidants neutralize free radicals as the natural by-product of normal cell processes. Free radicals are molecules with incomplete electron shells which make them more chemically reactive than those with complete electron shells. Exposure to various environmental factors, including tobacco smoke and radiation, can also lead to free radical formation. In humans, the most common form of free radicals is oxygen. When an oxygen molecule (O2) becomes electrically charged or “radicalized” it tries to steal electrons from other molecules, causing damage to the DNA and other molecules. Over time, such damage may become irreversible and lead to disease including cancer. Antioxidants are often described as “mopping up” free radicals, meaning they neutralize the electrical charge and prevent the free radical from taking electrons from other molecules.

Which foods are rich in antioxidants?
Antioxidants are abundant in fruits and vegetables, as well as in other foods including nuts, grains, and some meats, poultry, and fish. The list below describes food sources of common antioxidants.

Beta-carotene is found in many foods that are orange in color, including sweet potatoes, carrots, cantaloupe, squash, apricots, pumpkin, and mangos. Some green, leafy vegetables, including collard greens, spinach, and kale, are also rich in beta-carotene.

Lutein, best known for its association with healthy eyes, is abundant in green, leafy vegetables such as collard greens, spinach, and kale.

Lycopene is a potent antioxidant found in tomatoes, watermelon, guava, papaya, apricots, pink grapefruit, blood oranges, and other foods. Estimates suggest 85 percent of American dietary intake of lycopene comes from tomatoes and tomato products.

Selenium is a mineral, not an antioxidant nutrient. However, it is a component of antioxidant enzymes. Plant foods like rice and wheat are the major dietary sources of selenium in most countries. The amount of selenium in soil, which varies by region, determines the amount of selenium in the foods grown in that soil. Animals that eat grains or plants grown in selenium-rich soil have higher levels of selenium in their muscle. In the United States, meats and bread are common sources of dietary selenium. Brazil nuts also contain large quantities of selenium.

Vitamin A is found in three main forms: retinol (Vitamin A1), 3,4-didehydroretinol (Vitamin A2), and 3-hydroxy-retinol (Vitamin A3). Foods rich in vitamin A include liver, sweet potatoes, carrots, milk, egg yolks, and mozzarella cheese.

Vitamin C is also called ascorbic acid, and can be found in high abundance in many fruits and vegetables and is also found in cereals, beef, poultry, and fish.

Vitamin E, also known as alpha-tocopherol, is found in almonds, in many oils including wheat germ, safflower, corn, and soybean oils, and is also found in mangos, nuts, broccoli, and other foods.

thank you and references
http://www.webmd.com/food-recipes/tc/antioxidants-topic-overview
http://www.nlm.nih.gov/medlineplus/antioxidants.html
http://www.cancer.gov/cancertopics/factsheet/prevention/antioxidants
Blot WJ, Li JY, Taylor PR, et al. Nutrition intervention trials in Linxian, China: supplementation with specific vitamin/mineral combinations, cancer incidence, and disease-specific mortality in the general population. J Natl Cancer Inst 1993;85:1483–91
The Alpha-Tocopherol, Beta Carotene Cancer Prevention Study Group. The effects of vitamin E and beta carotene on the incidence of lung cancer and other cancers in male smokers. N Engl J Med 1994;330:1029–35.

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vitamin C

Posted on 12. Nov, 2010 by .

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Vitamin C is an antioxidant. Antioxidants are substances that may protect your cells against the effects of free radicals. Free radicals are molecules produced when your body breaks down food, or by environmental exposures like tobacco smoke and radiation. Vitamin C is important for your skin, bones, and connective tissue. It promotes healing and helps the body absorb iron.

Vitamin C comes from fruits and vegetables. Good sources include citrus, red and green peppers, tomatoes, broccoli, and greens. Some juices and cereals have added vitamin C.

Some people may need extra vitamin C:

* Pregnant/breastfeeding women
* Smokers
* People recovering from surgery
* Burn victims

Vitamin C (ascorbic acid) is a water-soluble vitamin, which is necessary in the body to form collagen in bones, cartilage, muscle, and blood vessels and aids in the absorption of iron. Dietary sources of vitamin C include fruits and vegetables, particularly citrus fruits such as oranges.

Severe deficiency of vitamin C causes scurvy. Although rare, scurvy includes potentially severe consequences, and can cause sudden death. Patients with scurvy are treated with vitamin C and should be under medical supervision.

Many uses for vitamin C have been proposed, but few have been found to be beneficial in scientific studies. In particular, research in asthma, cancer, and diabetes remains inconclusive, and no benefits have been found in the prevention of cataracts or heart disease.

The use of vitamin C in the prevention/treatment of the common cold and respiratory infections remains controversial, with ongoing research. For cold prevention , more than 30 clinical trials including over 10,000 participants have examined the effects of taking daily vitamin C. Overall, no significant reduction in the risk of developing colds has been observed. In people who developed colds while taking vitamin C, no difference in severity of symptoms has been seen overall, although a very small significant reduction in the duration of colds has been reported (approximately 10% in adults and 15% in children). Notably, a subset of studies in people living in extreme circumstances, including soldiers in sub-arctic exercises, skiers, and marathon runners, have found a significant reduction in the risk of developing a cold by approximately 50%. This area merits additional study and may be of particular interest to elite athletes or military personnel.

For cold treatment , numerous studies have examined the effects of starting vitamin C after the onset of cold symptoms. So far, no significant benefits have been observed.

references and thank you

http://www.mayoclinic.com/health/vitamin-c/NS_patient-vitaminc
http://www.nlm.nih.gov/medlineplus/vitaminc.html

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vitamin A

Posted on 02. Nov, 2010 by .

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Vitamin A, also called retinol, helps your eyes adjust to light changes when you come in from outside and also helps keep your eyes, skin and mucous membranes moist. Vitamin A mostly comes from animal foods, but some plant-based foods supply beta-carotene, which your body then converts into Vitamin A. It also has antioxidant properties that neutralize free radicals in the body that cause tissue and cellular damage. Early information from scientific studies suggests that beta-carotene might help people who already have Coronary Artery Disease (CAD) (ref1) If you’re pregnant, you should avoid eating liver because of the amount of vitamin A it contains. (ref. 2)

Sources of Vitamin A

Top sources of vitamin A include:

• Beef liver

• Egg yolk

• Cheddar cheese

• Fortified milk

Top sources of beta-carotene include:

• Sweet potato

• Carrots

• Pumpkin

• Cantaloupe

• Broccoli

• Apricots

• Spinach and collard greens

Can You Have Too Much or Too Little?

Vitamin A deficiency is rare in the United States, but it can cause night blindness, eye inflammation, diarrhea and other problems. Overconsumption of vitamin A can cause nausea, irritability and blurred vision in its mild form. In addition, the palms of the hands and the bottoms of the feet can turn orange if a person has a high intake of Vitamin A. Vitamin A toxicity can cause growth retardation, hair loss and enlarged spleen and liver in its more severe form. Vitamin A overdose can also cause birth defects and has been linked to increased risk of bone fractures in some people.

Vitamin Storage

If you want to get the most vitamins possible from your food, refrigerate fresh produce, and keep milk and grains away from strong light. Vitamins are easily destroyed and washed out during food preparation and storage. If you take vitamin supplements, store them at room temperature in a dry place that’s free of moisture.(ref. 2)

Recommendations

The best way to get the daily requirement of essential vitamins is to eat a balanced diet that contains a variety of foods from the food guide pyramid.

The Food and Nutrition Board at the Institute of Medicine recommends the following:

Infants

  • 0 – 6 months: 400 micrograms per day (mcg/day)
  • 7 – 12 months: 500 mcg/day

Children

  • 1 – 3 years: 300 mcg/day
  • 4 – 8 years: 400 mcg/day
  • 9 – 13 years: 600 mcg/day

Adolescents and Adults

  • Males age 14 and older: 900 mcg/day
  • Females age 14 and older: 700 mcg/day

Specific recommendations depend on age, gender, and other factors (such as pregnancy). Women who are pregnant or producing breast milk (lactating) need higher amounts. Ask your doctor what dose is best for you.(ref.3)

references and thank you

1 http://www.eatwell.gov.uk/healthydiet/nutritionessentials/vitaminsandminerals/vitamina/

2 http://www.lifeclinic.com/focus/nutrition/vitamin-a.asp

3http://www.nlm.nih.gov/medlineplus/ency/article/002400.htm

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Vitamin That Your Body Needs

Posted on 02. Nov, 2010 by .

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Vitamins are organic compounds which are needed in small quantities to sustain life. We get vitamins from food, because the human body either does not produce enough of them, or none at all.

An organic compound contains carbon. When an organism (living thing) cannot produce enough of an organic chemical compound that it needs in tiny amounts, and has to get it from food, it is called a vitamin.

Sometimes the compound is a vitamin for a human but not for some other animals. For example, vitamin C (ascorbic acid) is a vitamin for humans but not for dogs, because dogs can produce (synthesize) enough for their own needs, while humans cannot.

Vitamins are substances that your body needs to grow and develop normally. There are 13 vitamins your body needs. They are vitamins A, C, D, E, K and the B vitamins (thiamine, riboflavin, niacin, pantothenic acid, biotin, vitamin B-6, vitamin B-12 and folate). You can usually get all your vitamins from the foods you eat. Your body can also make vitamins D and K. People who eat a vegetarian diet may need to take a vitamin B12 supplement.
Each vitamin has specific jobs. If you have low levels of certain vitamins, you may develop a deficiency disease. For example, if you don’t get enough vitamin D, you could develop rickets. Some vitamins may help prevent medical problems. Vitamin A prevents night blindness.
The best way to get enough vitamins is to eat a balanced diet with a variety of foods. In some cases, you may need to take a daily multivitamin for optimal health. However, high doses of some vitamins can make you sick.

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