Vitamin E is actually not a single substance.  It includes 8 fat-soluble vitamins that are active throughout the body.  Some of the vitamins considered tocopherols; while the others are considered tocotrienols.  Alpha-tocopherol is the only form of vitamin E that is actively maintained in the human body; therefore, it is the form found in the larges quantities in blood and tissues (1). 

Prevents Oxidative Stress (aka anti-oxidation)

The principle function of vitamin E is that of an antioxidant.  Free radicals are formed in the body during normal metabolism and when we are exposed to environmental stressors, such as smoke and pollutants.  Fats are especially vulnerable to destruction by free radicals.  Prevention of damage from free radicals depends on a complex protective system of which vitamin E plays and essential role.  Other nutrients involved include: vitamin C, glutathione, selenium, and vitamin B3.  Some researchers believe vitamin E is the most important member of this oxidative stress-preventing group. 

• Heart Disease. Clinical trials with vitamin E along and with other antioxidants suggest that vitamin E may decrease LDL-cholesterol oxidation (2,3,4).  In fact, evidence of high intakes of vitamin E was shown to be associated with a lower risk of coronary heart disease in both men and women (5,6).  Research also found that supplementation with 800 IU alpha-tocopherol (Vitamin E) reduced the rate of nonfatal heart attacks in a group of patients with symptomatic heart disease after 1 year of treatment (7).  These findings have implication in preventing atherosclerosis, which is an accumulation of fatty materials in the artery.  
• Cataracts. Vitamin E has been suggested for the treatment or prevention of cataracts (8,9).  Cataracts results in part from oxidative damage to proteins that aggregate and precipitate in the lens of the eye, which causes cloudiness.

Protects Against Cancer

• Bladder Cancer. According to research presented at the annual meeting of the American Association of Cancer Research (Orlando, FL, May 23, 2004), eating foods rich in vitamin E, such as nuts, seeds, spinach, mustard greens, peppers, and olive oil can decrease one’s risk of developing bladder cancer by up to 50%.  Bladder cancer kills 12,500 Americans annually, and is the fourth leading cancer killer among men.  Whether intake was from foods or supplements, the reduction in risk was roughly the same.
• Prostate Cancer.  Research shows that vitamin E could inhibit the development of prostate cancer.  According to the researches from the Proceedings of the National Academy of Sciences, vitamin Es suppressed the production of a receptor for testosterone, which is the marker of this cancer’s development (10).  By lowering the number of testosterone receptors in a prostate cancer cell, the genes that stimulate cancer growth are less likely to be activated.  However, the form of vitamin E is essential.  It is suggested that gamma-tocopherol, but not alpha-tocopherol, inhibits prostate cancer proliferation, without affecting healthy prostate cells.  In another study in the Proceedings of the National Academy of Sciences found that it can be dangerous to take high doses of vitamin E in the form of alpha-tocopherol without consuming gamma tocopherol.  Gamma-tocopherol plays a critical role in the defense against cancer (and cardiovascular disease) by decreasing inflammation (11). 

Protects Against Alzheimer’s Disease

A high intake of vitamin E from food, but not from supplements, was shown to decrease the risk of Alzheimer’s disease.  According to the Chicago Healthy and Aging Project, participants with the highest intakes of vitamin E from food (contains other tocopherol forms besides alpha-tocopherol) had a 67% lower risk of Alzheimer’s (12). 

Deficiency Symptoms

A deficiency of vitamin E in humans is rare.  Usually the population groups exhibiting deficiency symptoms include premature, low-birth weight infants and people with malabsorption syndromes.  Some of the common symptoms of vitamin E deficiency include retinal degeneration, hemolytic anemia, muscle weakness, incoordination of limbs, and peripheral neuropathy (pain tingling, and loss of sensation in arms, hands, legs, and/or fee)

Nutrient Interactions

As mentioned above, the recycling of vitamin E in the body is connected to four other nutrients: vitamin C, glutathione, selenium, and vitamin B3.  Thus, vitamin E is heavily dependent on these substances.  On the other hand, moderately high levels of 1,000 mg or more of vitamin E can interfere with the function of vitamin K. 

Food Sources

According to the World’s Healthiest Foods…

Excellent sources of vitamin E include:

1) Mustard greens
2) Turnip greens
3) Chard
4) Sunflower seeds

Very good sources include:
1) Almonds
2) Spinach

Good sources include:
1) Collard greens
2) Parsley
3) Kale
4) Papaya
5) Olives
6) Bell peppers
7) Brussels sprouts
8) Kiwi
9) Tomato
10) Blueberries
11) Broccoli
 
How much?

The Recommend Daily Allowance (RDA) is 15 mg/day (22 IU) for adult men and women.  However, literature provides strong evidence that vitamin E intakes much For example, the amount of vitamin E needed to protect polyunsaturated fats against oxidative damage is at least 135-150 Ius (13, 14).  Additionally, Vitamin E intakes of at least 200 IU/day enhanced immune responses (15) and intakes of 100-400 IU/day decreased platelet adhesion to the arterial wall.  Scientist at the Linus Pualing Institute feel there is credible evidence that support taking a supplement of 200 IU (134 mg) of natural sources d-alpha-tocopherol (RRR-alpha-tocopherol) daily with a meal may help protect adults from chronic diseases, such as heart disease, stroke, neurodegenerative diseases, and some types of cancer (17). The amount of alpha-tocopherol required for such beneficial effects appears to be much greater than that which could be achieved through diet alone. Life Time Fitness’s Men’s and Women’s Performance Multivitamins provide 200 IU in the AM formula and 200 IU in the PM formula. 

References

1) Traber MG. Utilization of vitamin E. Biofactors. 1999;10(2-3):115-120
2) Nike E, Noguchi N, Tsuchihashi H, Gotoh N.  Interaction among vitamin C, vitamin E, and B-carotene. Am J Clin Nutr, 1995; 62(suppl):1233S-26S.
3) Jialal I, Grundy S. Effect of dietary supplementation with alpha tocopherol on the oxidative modification of low density lipoprotein. J Lipid Res, 1992;33:899-906. 
4) Esterbauer H, Dierber-Rotheneder M, Striegl G, Waeg G. Role of vitamin E in preventing the oxidation of low-density lipoprotein. Am J Clin Nutr, 1991;53:314S-21S.
5) Stampfer M, Hennekens C, Manson J, Colditz Gm Rosner Bm Willett W. Vitamin E consumption and the risk of coronary disease in women. N Eng J Med; 1993;328:1444-9.
6) Rimm E, Stampfer M, Asherio A, Giovannucci E, Colditz G, Willett W. Vitamin E consumption and the risk of coronary heart disease in men. N Eng J Med, 1993;328:1450-6.
7) Stephens N, Parsons A, Schofield P, Kelly F, Cheeseman K, Mitchinson M, Brown M. Randomized controlled trial of vitamin E in patients with coronary disease: Cambridge Heart Antioxidant Study (CHAOS). Lancet 1996;347:781-6.
8) Varma S. Scientific basis for medical therapy of cataracts by antioxidants. A, J Clin Nutr, 1991; 53:335S-45S.
9) Robertson J, Donner A, Trevithick J. A possible role for vitamin S and vitamin E in cataract prevention. Am J Clin Nutr 1995:62suppl):1337S-46S.
10) Jiang Q, Wong J, Fyrst H, Saba JD, Ames BN. gamma-Tocopherol or combinations of vitamin E forms induce cell death in human prostate cancer cells by interrupting sphingolipid synthesis. Proc Natl Acad Sci U S A. 2004 Dec 21;101(51):17825-30. 2004. PMID:15596715
11) Proceedings of the National Academy of Sciences. April 1997;94;3217-3222.
12) Morris MC, Evans DA, Tangney CC, Bienias JL, Wilson RS, Aggarwal NT, Scherr PA. Relation of the tocoperol forms to incident Alzheimer disease and to cognitive change. Am J Clin Nutr. 2005 Feb;81(2):508-14. 2005. PMID:15699242.
13) Haegele AD, Briggs SP, & Thompson HJ. Antioxidant status and dietary lipid unsaturation modulate oxidation DNA damage. Free Rad Biol Med, 1994;16:111-115.
14) Summerfield FW & Tappel AL.  Effects of dietary polyunsaturated fasts and vitamin E on aging and peroxidative damage to DNA. Arch Biochem Biophys, 1984; 233:408-416.
15) Meydani SN, Meydani M, Blumberg JB, Leka LS, Siber G, Loszewski R, et al. Vitamin E supplementation and in vivo immune response in healthy elderly subjects. A randomized controlled trial. JAMA. 1997;277:1380-6. [PMID: 9134944]
16) Pyror W. Vitamin E and heart disease: Basic science to clinical intervention trials. Free Rad Biol Med, 2000;28:141-164.
17) Linus Pauling Institute: Micronutrient Research for Optimal Health. Oregan State University. http://lpi.oregonstate.edu/infocenter/vitamins/vitaminE/