Vitamin E

Vitamin E is a term used to describe two groups of compounds known as the tocopherols and the tocotrienols. The most active of these is alpha-tocopherol, and the vitamin E content of foods and supplements is usually expressed in terms of 'alpha-tocopherol equivalents.

All compounds with vitamin E activity are fat-soluble and readily stored in the body. Sometimes the amount of vitamin E is expressed in International Units (IU) rather than milligrams.

1IU = 0.67mg alpha-tocopherol equivalents or conversely: 1mg = 1.5IU

Synthetic alpha-tocopherol has less biological strength than naturally sourced vitamin E due to the different symmetries of its molecules.

Why you need it

Vitamin E mainly acts as an antioxidant in the body. As it is fat soluble, it protects body fats from the harmful effects of free radicals -- cell membranes, nerve sheaths, circulating cholesterol molecules, dietary fats and body fat stores from oxidative damage and rancidity. In general, the more polyunsaturated fatty acids you eat, the more vitamin E that you'll need, because polyunsaturated fats are prone to rapid oxidation and rancidity.

Vitamin has a strengthening effect on muscle fibres (relieving muscle cramps), boosts the immune system and improves skin suppleness and healing. It also seems to improve glucose use in the body and better response to insulin hormone in those with diabetes.

Research

Vitamin E has a protective effects against coronary heart disease. Hardening and furring up of the arteries (atherosclerosis) is now recognised as an inflammatory response to damage to arterial walls, which triggers the over-production of free radicals. By neutralising these free radicals, vitamin E helps to protect artery walls from atherosclerosis. As well as its antioxidant effect, vitamin E helps blood vessels dilate, and reduces blood clotting. As a result, it has a powerful protective effect in the circulation.

In a study involving over 125,000 people, the risk of coronary heart disease was reduced by up to 50 per cent in women and 25 per cent in men who had taken vitamin E supplements for two years or more.

Vitamin E gained widespread medical acceptance following results of the Cambridge Heart Antioxidant Study (CHAOS) in 1996. Just over 2,000 patients with coronary heart disease were divided into two groups. Half took vitamin E for 18 months, while the other half received a placebo. Taking a high dose of vitamin E (400 or 800IU daily = 268mg or 536mg) was found to reduce the risk of a heart attack by 77 per cent. Not only was the difference highly statistically significant, it was concluded that the group treated with vitamin E were now under no greater risk of a heart attack than people without coronary heart disease at all. As a result, many physicians now recommend high dose vitamin E supplements for those at risk from heart attacks. The results need further investigation, however, as not all trials have correlated.

Smokers generate a large number of free radicals which are linked with a number of diseases, including coronary heart disease, high blood pressure, stroke, osteoporosis and cancer. Low dietary intakes of antioxidant vitamins (such as vitamins C and E) increase the risk of these illnesses, whereas high dietary intakes seem to be protective.

Vitamin E and cancer

Vitamin E does appear to protect against some cancers. A prospective cohort study of 35,215 women found a strong reduction in colon cancer risk in those with high intakes of vitamin E supplements in women under the age of 65.

An interesting study of over 11,000 people aged 67 years and over found that those taking vitamin E had a reduced risk of death at any age by around a third compared with those not taking vitamin E supplements. Risk of death from coronary heart disease was reduced by 63 per cent, and risk of death from cancer by 59 per cent. These results took account of other factors such as alcohol use, smoking history, aspirin use and known medical conditions.

A diet high in vitamin E seems to provide some protection against cataracts and age-related macular degeneration -- both conditions that can cause loss of sight in later life.

Vitamin E and the skin

In a trial, where volunteers took combined supplements of vitamins E (1000IU = 667mg) and vitamin C (2000mg) daily, they were shown to protect against UV induced sunburn damage by increasing the amount of UV exposure needed to cause reddening of skin. The researchers suggest that this may indicate a future reduced risk of the effects of sun damage (such as some forms of skin cancer) in people taking a high-dose of antioxidant supplements.

Vitamin E creams are often used to improve the quality of skin-healing after surgery (although some people develop allergic reactions to it).

Other studies have shown that vitamin E is beneficial in the treatment of peripheral vascular disease and neurological problems such as Parkinson's Disease, tardive dyskinesia and epilepsy.

Some studies have found that vitamin E intake is linked with lung function in older people. For every 1mg increase in vitamin E in the daily diet, the amount of air that can be blown out in one second increases by 42ml, for example.

How much you need

The EC RDA for vitamin E is 10mg.

Vitamin C is needed to regenerate vitamin E after it has acted as an antioxidant. Therefore, adequate supplies of both vitamins are essential. High intakes of vitamin E can be toxic, but this only usually occurs at doses 3000mg daily (300 times the recommended daily intake).

Symptoms that may be due to lack of vitamin E include

Lack of vitamin E has a harmful effect on the nervous system and can produce symptoms such as:

  • Lack of energy
  • Lethargy
  • Poor concentration
  • Irritability
  • Lowered sex drive
  • Muscle weakness
  • Poor co-ordination

In long-term lack of vitamin E (when it is not absorbed properly, for example), serious effects such as blindness, dementia and abnormal heart rhythms can occur.

Foods containing vitamin E include

  • Wheatgerm oil
  • Avocado pear
  • Margarine
  • Eggs
  • Butter
  • Wholemeal cereals
  • Seeds
  • Nuts
  • Bread
  • Oily fish
  • Broccoli

Vitamin E is unstable when frozen -- up to 80 per cent of the vitamin E content is destroyed. Heating destroys around 30 per cent vitamin E content, so fresh raw foods and supplements are therefore the best sources of it.


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