Vitamin E has been shown to protect the body against oxidative stress – the damage caused by compounds known as 'free radicals'. These are formed from the conversion of foods to energy, and external factors such as air pollution, cigarette smoke and UV light from the sun. Oxidative stress is linked to the development of various conditions including heart disease, arthritis and cataracts, as well as premature ageing.
Dr Sarah Brewer says: 'Vitamin E is one of the most important antioxidants in the body and protects fatty structures such as cell membranes from oxidative damage. Supplements are popular for supporting maintenance of skin and hair as well as for all-round good health. As it is fat-soluble, you may not obtain good amounts of vitamin E if you follow a low-fat diet, though it is stored in fat cells so you don't have to eat it every day.'
What does vitamin E do?
There are eight naturally-occurring forms of vitamin E, collectively called tocochromanols. They protect cell membranes from oxidative stress, inhibit the production of free radicals and neutralise existing ones which can prevent or delay chronic diseases associated with oxidative stress.
Vitamin E also helps to widen blood vessels and keeps blood from clotting. It plays a role in anti-inflammatory processes and has an immune-enhancing activity.
Vitamin E helps to stimulate the body's immune responses. One study in people aged over 60 found those with higher vitamin E levels had fewer viral infections over a three-year period than those with lower vitamin E status. Another trial found that four months of 200mg daily vitamin E supplementation significantly increased antibody production to certain vaccines.
Vitamin E is believed to play a role in heart and circulatory health by relaxing the blood vessels and thinning the blood. However, the clinical trial evidence is conflicting. Earlier trials found vitamin E may protect against heart disease in middle-aged and older women, but later studies did not find this effect.
Getting vitamin E from your diet
Vitamin E is found in foods containing 'good' fats, including wheatgerm oil, sunflower seeds, dry roasted almonds and sunflower oil. Lower amounts are also found in green leafy vegetables.
Experts say it may be more difficult to get enough vitamin E if you are following a very low fat diet, and supplements can be useful in these situations.
Vitamin E deficiency is rare and affects people with a reduced ability to absorb fat in the gut due to a bowel disorder or cystic fibrosis; a genetic condition in which the lungs and digestive system can become clogged with mucus.
Vitamin E is well tolerated, but at very high doses it can cause headaches, fatigue, muscle weakness, double vision and gastrointestinal symptoms. Combining a supplement with food increases absorption and lessens the chance of suffering any stomach irritation. The safe upper daily limit is 540mg.
The recommended nutritional intake for vitamin E is 4mg a day for men and 3mg a day for women. Supplement doses are available as one to two 200i.u. (134mg) capsules a day or as a 400i.u. (268mg) one-a-day capsule.