Vitamin E


Vitamin E was discovered in the 1920s when rats fed a vitamin E- deficient diet became unable to reproduce; but it was not officially considered essential for humans until 1966. It is the name given to a group of fat soluble compounds which are also called tocopherols and tocotrienols. The term "tocopherol" comes from the Greek words meaning "to bear offspring". The most abundant and active form of vitamin E is alpha tocopherol.

What it does in the body

Antioxidant properties

Unlike the other vitamins which take part in metabolic reactions or function as hormones, the main role of vitamin E appears to be to act as an antioxidant. Vitamin E is incorporated into the lipid portion of cell membranes and carrier molecules and protects these structures from toxic compounds, heavy metals, drugs, radiation and free radicals. Vitamin E also protects cholesterol from oxidative damage. Because of its antioxidant effects, a diet high in vitamin E appears to be protective against common health conditions such as heart disease, cancer and strokes.

Immune system

Vitamin E is essential for the maintenance of a healthy immune system as it protects the thymus gland and circulating white blood cells from damage. Vitamin E is particularly important in protecting the immune system from damage during times of oxidative stress and chronic viral illness.


Vitamin E is vital for healthy eyes. It is essential for the development of the retina and protects the eyes against free radical damage associated with cataract formation and macular degeneration. It also protects vitamin A in the eyes from damage.


As an antioxidant, vitamin E may protect against the effects of aging by destroying free radicals which cause degeneration in tissues such as the skin and blood vessels. Studies in mice have shown that high doses of vitamin E may help prevent aging-related damage to proteins involved in immune and central nervous system function. Vitamin E may also protect against the mental effects of aging, such as memory loss.

Absorption and metabolism

Vitamin E requires the presence of fats and bile in the gut to be absorbed. Approximately 20 to 60 per cent of dietary vitamin E is absorbed and it is stored in the liver, heart, fatty tissues, heart, muscles, testes, uterus, blood, adrenal and pituitary glands. Absorption and transport are likely to be reduced in elderly people.


The symptoms of vitamin E deficiency in infants are irritability, fluid retention, hemolytic anemia (the breaking down of red blood cells) and eye disorders. In adults, vitamin E deficiency can lead to nerve damage and symptoms of lethargy, apathy, inability to concentrate, staggering gait, low thyroid hormone levels, decreased immune response, loss of balance and anemia.

Severe vitamin E deficiency is very rare. Those at risk include people with chronic liver disease and fat malabsorption syndromes, such as celiac disease and cystic fibrosis. Hemodialysis patients, those with inherited red blood cell disorders, premature and low birthweight infants, and elderly people may also be at risk of vitamin E deficiency and are often given supplements.

As vitamin E is stored in the body, it can take some time before deficiency symptoms become apparent in someone consuming a diet low in vitamin E. Marginal vitamin E deficiency may be relatively common and several studies have shown an increased risk of heart disease, cancer and other disorders in those with low vitamin E levels.

Cardiovascular disease

Low dietary intake of vitamin E seems to increase the risk of heart disease. This is illustrated by results from the Iowa Women's Health Study published in 1996 in the New England Journal of Medicine. Researchers studied 34,486 postmenopausal women with no cardiovascular disease who in early 1986 completed a questionnaire that assessed, among other factors, their intake of vitamins A, E, and C from food sources and supplements. During seven years of follow-up, 242 women died of coronary heart disease. The results showed that high vitamin E consumption reduced the risk of death from coronary heart disease. This association was particularly striking in the subgroup of 21 809 women who did not consume vitamin supplements.1

Similar results have been seen in men. Harvard School of Public Health researchers have assessed the links between diet and heart disease in 39 910 US male health professionals aged between 40 to 75 years of age. Participants responded to a questionnaire in 1986 and were then followed up for four years, during which time there were 667 cases of coronary disease. The results showed a lower risk of disease among men with higher intakes of vitamin E. Men consuming more than 40 mg (60 IU) per day had a 36 per cent lower risk than those consuming less than 5 mg (7.5 IU) per day. Men who took at least 67 mg (100 IU) per day for at least two years had a 37 per cent lower risk than those who did not take supplements.2

The results of a 1996 study done in Japan suggest that low vitamin E levels increase the risk of a type of angina caused by coronary artery spasm.3 Animal studies suggest that brain damage after stroke may be greater in those who are vitamin E-deficient


There is some evidence that vitamin E can protect against cancer, although studies have shown conflicting results. Some population studies suggest that low vitamin E levels increase the risk of certain cancers, particularly those of the gastrointestinal tract, cervix and lungs.

Cancers of the gastrointestinal tract

Results from the Iowa Women's Health Study suggest that high intakes of vitamin E reduce the risk of colon cancer. Researchers analyzed the links between vitamin E and colon cancer in 35 215 Iowa women aged 55 to 69 years without a history of cancer. During the follow-up period, there were 212 cases of colon cancer. The results showed that low vitamin E intake increased the risk of colon cancer and those in the high intake group had 30 per cent of the risk of those in the low intake group. The protective factor was stronger in the younger women.4

Other results from the Iowa Women's Health Study show that higher intakes of antioxidants, including vitamin E, are linked to lower risks of both oral, pharyngeal, esophageal and gastric cancers.5

Breast cancer

Researchers at the University of Southern California investigated the relationship between blood levels of various nutrients, including vitamin E, and the risks of breast cancer and proliferative benign breast disease (BBD) in postmenopausal women in the Boston area. Women whose intake of vitamin E from food sources only was high had around 60 per cent less risk of breast cancer compared to those in the low intake group.6 However, not all studies have shown protective effects.7

Cervical cancer

Utah University researchers investigating the relationship between cervical cancer and dietary intake of antioxidant vitamins and selenium in 266 women with cervical cancer and 408 women without the disorder found that women with high vitamin E intakes had a 40 per cent lower risk of cervical cancer.8 Blood levels of vitamin E have also been found to be low in women with cervical cancer.9

Lung cancer

Several epidemiological studies suggest that low vitamin E intakes increase the risk of lung cancer. In 1974 and 1975, researchers at Johns Hopkins School of Hygiene and Public Health, Baltimore, collected blood samples from 25 802 volunteers. They assessed vitamin E levels in samples from 436 cancer cases and 765 matched control subjects. The results showed that high vitamin E levels protected against lung cancer.10


Low vitamin E levels may increase the risk of cataract formation. A 1996 Finnish study of over 400 men found an increased risk of cataracts in those with low vitamin E levels. The researchers evaluated the link between vitamin E levels and progression of eye lens opacities in 410 men with high cholesterol. The results showed that those with low vitamin E levels had almost four times the risk of lens opacities when compared with those in the highest intake group.11

Parkinson's disease

The results of several studies suggest that high levels of vitamin E can protect against Parkinson's disease. In a 1997 study, researchers at Erasmus University Medical School in Holland examined the relationship between dietary intake of antioxidants and Parkinson's Disease and found a reduction in risk associated with high vitamin E intake. The study involved over 5300 men and women living independently and without dementia. It included 31 people with Parkinson's Disease.12

Other symptoms

Low levels of vitamin E are common in those who are HIV-positive and high levels seem to be linked to slower disease progression. Vitamin E deficiency may also be involved in the development of pre-eclampsia.


The best natural sources of vitamin E are wheatgerm oil, hazelnut oil, sunflower oil, almond oil, wheatgerm, whole grain cereals and eggs. Peaches, avocados, broccoli and leafy greens are also good sources. Different foods have varying amounts of the different forms of vitamin E. For example, soybean oil is composed of about 10 per cent alpha tocopherol with the rest made up of other tocopherols. The specific benefits of the different forms of vitamin E remain to be discovered.

The results of a 1997 study suggest that the mixed forms of vitamin E found in food may be more beneficial than the alpha tocopherol form which is the main ingredient in supplements. Scientists at the University of California compared the abilities of alpha tocopherol and gamma tocopherol to protect against lipid peroxidation by compounds known as peroxynitrites which are formed in response to cigarette smoke, pollution and inflammation. Results showed that the gamma tocopherol form may be better at inhibiting these damaging reactions. About 75 per cent of the vitamin E found in food is the gamma tocopherol form while supplements may not contain any gamma tocopherol and it is possible that taking very high doses of alpha tocopherol may displace gamma tocopherol.13

Cooking and processing reduces the vitamin E content of foods such as flours and oils. Cold-pressed oils therefore have a higher vitamin E content than refined vegetable oils. Exposure to light and oxygen also destroys vitamin E.

Wheatgerm oil 1 tbsp 26.2 mg alpha TE

Wheatgerm cereal 1 cup 19.5 mg alpha TE

Sunflower seeds ¼ cup 17.2 mg alpha TE

Hazelnuts ½ cup, whole 15.4 mg alpha TE

Peanuts ½ cup, whole 6.32 mg alpha TE

Soy beans, cooked 1 cup 3.19 mg alpha TE

Safflower oil 1tbsp 4.69 mg alpha TE

Canola oil 1 tbsp 2.93 mg alpha TE

Corn oil 1 tbsp 2.87 mg alpha TE

Avocado 1 avocado 2.69 mg alpha TE

Soybean oil 1 tbsp 2.50 mg alpha TE

Spinach, cooked 1 cup 1.63 mg alpha TE

Tomato sauce, canned ½ cup 1.63 mg alpha TE

Olive oil 1 tbsp 1.68 mg alpha TE

Broccoli ½ cup, chopped 1.25 mg alpha TE

Grapes 1 cup 1.06 mg alpha TE

Blackberries 1 cup 0.97 mg alpha TE

Parsnip, cooked ½ cup, slices 0.74 mg alpha TE

Peaches 1 medium 0.69 mg alpha TE

Brussels sprouts, cooked ½ cup 0.63 mg alpha TE

Margarine 1tsp 0.60 mg alpha TE

Eggs 1 large 0.53 mg alpha TE

Tomatoes 1 medium 0.47 mg alpha TE

Beet greens, cooked 1 cup 0.41 mg alpha TE

Recommended dietary allowances

The amount of vitamin E required depends on the amount of polyunsaturated fats in the diet. The greater the amount of these fats in the diet, the greater the risk that they will be damaged by free radicals and exert harmful effects. As vitamin E prevents this damage, recommended intake is roughly proportional to the amount of polyunsaturated fats in the diet. The US RDA is based on an intake of 0.4 mg per g of polyunsaturated fats. Vitamin E is measured in International Units (IU) and more commonly nowadays, mg alpha TE. 1 IU equals 0.67 mg alpha TE.


Men 10 mg alpha TE (15 IU)

Women 8 mg alpha TE (12 IU)

Pregnancy 10 mg alpha TE (15 IU)

Lactation 12 mg alpha TE (18 IU)


Men 10 mg alpha TE (15 IU)

Women 7 mg alpha TE (10.4)

Pregnancy 7 mg alpha TE (10.4)

Lactation 9.5 mg alpha TE (14 IU)

No RNI has been given in the UK. A 1991 Department of Health report concluded that a fixed amount is impossible to recommend as required vitamin E needs depend on the intake of polyunsaturated fats, which varies considerably from person to person.


Vitamin E supplements are available in natural and synthetic forms. Natural forms of vitamin E are derived from soybean or wheatgerm oil and are indicated by a 'd' prefix. These include d-alpha-tocopherol, d-alpha-tocopheryl acetate and d-alpha-tocopheryl succinate. The synthetic forms are manufactured from purified petroleum oil and are indicated by a 'dl' prefix. These include dl-alpha-tocopherol, dl-alpha-tocopheryl acetate and dl-alpha-tocopheryl succinate. Natural vitamin E supplements containing mixed tocopherols appear to offer the most beneficial effects. Water soluble vitamin E supplements are also available and, although more expensive, may not necessarily be more beneficial. As they require fat for absorption, vitamin E supplements should be taken with food.

In studies where benefits of vitamin E supplementation have been shown, the doses used have usually well exceeded the RDAs. In many studies, daily doses of up to 536 mg (800 IU) or even 804 mg (1200 IU) have been used.