Vitamin E
This section is compiled by Frank M. Painter, D.C.
Send all comments or additions to: Frankp@chiro.orgIf there are terms in these articles you don't understand, you can get a definition from the Merriam Webster Medical Dictionary. If you want information about a specific disease, you can access the Merck Manual. You can also search Pub Med for more abstracts on this topic.
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Vitamin E and: Cancer Heart Disease Immune System Aging
Conditions That Respond Well Alternative Medicine Approaches to Disease
Vitamin E Articles
Flawed Meta-Analysis Misrepresents Vitamin E Research
November 16, 2004 –– A flawed "retrospective review" published in the Annals of Internal Medicine took a narrow look at only 19 of the more than 2,170 published papers addressing the efficacy and safety of Vitamin E. Strangely, "18 of those 19 clinical studies showed no increase in the risk for health complications or fatalities with Vitamin E versus a control group. Only one study out of the 19 demonstrated a higher risk and that study was with patients who were using estrogen hormone replacement therapy (HRT) along with Vitamin E."
Dietary Supplement Information Bureau
"Do not throw away your vitamin E," said C. Wayne Callaway, MD, Internal Medicine, Endocrinology, Metabolism and Clinical Nutrition. "One study does not outweigh the many studies that document the benefits of vitamin E in people who need it and the lack of harm in people who do not." In response to the meta-analysis, the DSIB launched a new Web site - www.vitaminEfacts.org - to help consumers obtain accurate information on vitamin E.
WASHINGTON, May 22, 1997 –– A new report by the National Defense Council Foundation finds that the federal government could save up to $6.3 billion annually by increasing the health of active and retired military personnel through a anti–aging program that includes the use of Vitamin E supplementation.
Eight natural compounds have vitamin E activity. These are the four tocopherols, designated as alpha, beta, gamma and delta, and four tocotrienols also designated as alpha, beta, gamma and delta. Yet, alpha-tocopherol has become synonymous with vitamin E. It is the most bioactive form based on the rat foetal resorption test, the classical assay for vitamin E activity. Recent research, however, shows that the other tocopherols and tocotrienols have important and unique antioxidant and other biological effects in nutrition and health. [ 1,2 ] This paper will review the biological function of tocopherols and tocotrienols and their role in health and disease.
On a supplement label, natural vitamin E is listed as d-alpha tocopherol, d-alpha tocopheryl acetate, or d-alpha tocopheryl succinate. In contrast, synthetic forms of vitamin E are labeled with a dl- prefix. Alpha-tocopherol is the most biologically active form of vitamin E, and its natural form consists of one isomer. In contrast, synthetic alpha-tocopherol contains eight different isomers, of which only one (about 12 percent of the synthetic molecule) is identical to natural vitamin E. The other seven isomers range in potency from 21 percent to 90 percent of natural d-alpha-tocopherol.
For decades vitamin E has maintained a position along with vitamin C and calcium as one of the three most popular single-ingredient dietary supplements. As scientists continue to examine the role of free radicals in disease initiation and promotion, research substantiates this potent antioxidant's ability to treat stroke, cardiovascular disease and cancer.
Researchers have discovered a new role for vitamin E in heart disease protection. Vitamin E supplements lowered blood levels of two key substances that contribute to atherosclerosis, according to a study conducted at the University of Texas Southwestern Medical Center in Dallas. This may be especially important for diabetics who are at high risk of heart disease and have circulatory problems.
Next to vitamin C, vitamin E is probably the most well-known vitamin. In an informal survey I conducted among acquaintances, adults could tell me that alpha-tocopherol is vitamin E and that it is an antioxidant. Many people were aware of claims that vitamin E supplementation slows aging, improves immunity, protects against cancer and heart disease, and is generally good for health. But not many people knew if they got enough. Not even doctors are clear if vitamin E supplements are necessary to prevent deficiency.
Researchers have long known that natural vitamin E, milligram for milligram, is about 36 percent more potent than the synthetic form of the vitamin. In fact, the "international unit," or IU, standard was developed to compensate for these differences. But two new studies using different groups of people - not laboratory animals - have found that natural vitamin E is utilized twice as efficiently as the synthetic form.
Vitamin E and Cancer
J Toxicol Environ Health A 2001 (Oct 12); 64 (3): 213–222
The obtained results indicate significant changes in antioxidant capacity of colorectal cancer tissues, which lead to enhanced action of oxygen radicals, resulting in lipid peroxidation.
Cancer Causes Control 2001 (Sep); 12 (7): 627–633
To conduct timely epidemiologic investigations of molecular/genetic markers that may contribute to the development of prostate, lung, colorectal, or other cancers within the Selenium and Vitamin E Cancer Prevention Trial (SELECT), and to evaluate interactions between these markers and the study interventions.
J Natl Cancer Inst 1998 (Mar 18); 90 (6): 440—446
Long-term supplementation with alpha-tocopherol substantially reduced prostate cancer incidence and mortality in male smokers. Other controlled trials are required to confirm the findings.
NOTE: This trial caused enough of a stir to stimulate the initiation of the SELECT (Selenium and Vitamin E Cancer Prevention Trial).
Eur J Cancer B Oral Oncol 1993 (Oct); 29B (4): 313–318
These observations suggest that vitamin E may inhibit cancer formation by stimulating the expression of a cancer suppressor gene.
Vitamin E and Heart Disease
Alternative Medicine Review 1999 (Dec); 4 (6): 414–423 ~ FULL TEXT
On the basis of the literature search, the authors recommend 400 IU or more per day of vitamin E to patients at high risk or already diagnosed with coronary artery disease. Vitamin E supplementation may also be beneficial in the prevention of cerebro- and peripheral vascular diseases.
Vitamin E and the Immune System
Clin Infect Dis 2001 (Dec 1); 33 (11): 1892–1900
Older adults are at risk for malnutrition, which may contribute to their increased risk of infection. Nutritional supplementation strategies can reduce this risk and reverse some of the immune dysfunction associated with advanced age.
Am J Clin Nutr 1990 (Sep); 52 (3): 557–563
Short-term vitamin E supplementation improves immune responsiveness in healthy elderly individuals; this effect appears to be mediated by a decrease in PGE2 and/or other lipid-peroxidation products.
Vitamin E and Aging
J Nutr 2001 (Feb); 131 (2): 382S–388S
Researchers have found that vitamin E supplements can improve rheumatoid arthritis symptoms and reduce markers of inflammation. In a recent study with laboratory mice, Simin Nikbin Meydani, D.V.M., Ph.D., of Tufts University in Boston, found that peroxynitrite, a free radical built around an oxygen and nitrogen molecule, in-creased activity of cyclooxygenase-2 (cox-2), an enzyme involved in making inflammatory prostaglandins. Giving the mice extra vitamin E reduced cox-2 and proinflammatory prostaglandin E2 levels.
J Am Geriatr Soc 2000 (Oct); 48 (10): 1285–1291
These results suggest that increased levels of oxidative stress and/or antioxidant deficiencies may pose risk factors for cognitive decline. The direct implication of oxidative stress in vascular and neurodegenerative mechanisms that lead to cognitive impairment should be further explored.
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