Vitamin (fat-soluble)

• UK RNI None
• US RDA 10 mg (7 iu)

Functions

• Antioxidant, especially combating peroxidation of unsaturated fats in cell membranes
• Development and maintenance of nerve and muscle function
• Fertility
• Immunity
• Preventing photooxidative damage to eye lens
• Prostaglandin modulation
• Red cell membrane stability
• Reduces oxygen needs of muscles
• Spares vitamin A

Good food sources

• Almonds
• Butter
• Leafy green vegetables
• Oats
• Peanuts
• Soya oil
• Sunflower oil and seeds
• Wheat germ and wheat germ oil
• Whole grains

Deficiency signs and symptoms

• Age spots (accumulation of lipofuscin)
• Cataracts
• Damage to cell membranes
• Increased red cell fragility and haemorrhaging
• Infertility
• Muscle weakness
• Neuromuscular damage
• Possibly autoimmune diseases such as lupus

Preventing deficiency

Many countries make the replacement of some of the lost B vitamins compulsory in products made from refined (white) flour, since the B vitamins are, like vitamin E, mostly found in the germ of the flour, not in the white, starchy portion. Unfortunately vitamin E is not replaced in this way although 92 per cent of vitamin E in wheat is lost when flour is refined, and most of the rest is destroyed by bleaching.

Cooking food in fats destroys 70 to 90 per cent of the fats' vitamin E content, especially when the fats are old or rancid. Boiling destroys about one third of the vitamin E in carrots, cabbages and brussels sprouts. The storage of foods, even when frozen, can result in heavy vitamin E losses, e.g. frozen French fries can lose up to 74 per cent after two months' storage. Two thirds of the vitamin E can be lost during the production of commercial vegetable oils. Fat malabsorption causes deficiency.

Vitamin E needs are related to the intake of polyunsaturated fats because vitamin E is used up in the process of preventing their oxidation.The bioavailability of Vitamin E is decreased by an excessive intake of polyunsaturated fats.

Vitamin C and the amino acid glutathione have a sparing effect on vitamin E.

Smoking can lead to a vitamin E deficiency (Pacht ER et al: Deficiency of vitamin E in the alveolar fluid of cigarette smokers. Influence on alveolar macrophage cytotoxicity. J Clin Invest 77(3):789-96, 1986). Levels of vitamin E are also significantly lower in users of the contraceptive pill (Tangney CC et al: Vitamin E status of young women on combined-type oral contraceptives. Contraception 17(6):499-512, 1978.)

Comments

Vitamin E is one of a group of nutrients known as tocopherols. The tocopherol with the greatest vitamin E activity is thought to be alpha-tocopherol, but as yet we know very little about the roles of the other tocopherols in health, and it cannot be assumed that they are without value. Tocopherols are found in conjunction with plant oils, especially those with polyunsaturated oils, and are concentrated in the germ.

Severe vitamin E deficiency has marked similarities to two diseases: muscular dystrophy and myasthenia gravis, which both involve increasing muscle weakness and dysfunction. Other symptoms of these diseases which also occur in vitamin E deficiency include age spots, low plasma vitamin E concentrations, creatinuria, and increased plasma creatine phosphokinase activity (all indicative of muscle cell damage). The same symptomatology is also seen in conditions where there is intestinal malabsorption of fat: cystic fibrosis of the pancreas, biliary atresia or cirrhosis, sprue and chronic pancreatitis.

SUPPLEMENTATION

In research studies, Vitamin E supplements have been found to:

• Delay the progress of Parkinson's disease
• Enhance a variety of immune system responses
• Halve the risk of heart attack in those with heart disease
• Heal some cases of gangrene
• Help heal sunburn when applied directly to the skin
• Help reduce tardive dyskinesia (jerky movements) in patients taking anti-schizophrenic drugs
• Improve epileptic seizure control
• Improve macular degeneration of the eyes
• Improve mobility and reduce pain in osteoarthritis
• Improve premenstrual syndrome
• Improve systemic lupus erythematosus
• Increase levels of HDL ('good') cholesterol
• Inhibit platelet adhesiveness (blood stickiness)
• Prevent cataracts
• Reduce capillary fragility and hyperpermeability
• Reduce some complications of diabetes and enhance insulin action
• Reduce liver damage from carbon tetrachloride
• Reduce pain from shingles as well as other types of chronic pain
• Reduce scars when applied directly to the skin
• Reduce the harmful effects of inhaling ozone, nitrogen oxides and other constituents of smog or cigarette smoke
• Reduce the incidence of mammary tumours in experimental animals
• Reduce the number of irreversibly sickled cells in sickle cell anaemia
• Suppress the formation of faecal mutagens
• Treat cystic breast disease and mammary dysplasia
• Treat intermittent claudication (painful condition of the legs in cardiovascular disease)
• Treat menopausal symptoms
• Treat some types of neuropathy
• With selenium, improve muscular dystrophy
• With vitamin A, improve some cases of hearing loss

Preferred form and suggested intake

Although vitamin E is available as mixed tocopherols, most supplements consist only of alpha tocopherol, which has the highest vitamin E activity. For preventive health purposes 100-200 iu a day is probably more than adequate. For long-standing symptoms thought to be related to vitamin E deficiency, up to 1,000 iu can be taken safely by most individuals.

Cautions

Do not take vitamin E supplements without a doctor's advice if you are taking anti-coagulant drugs, since vitamin E can itself act as an anticoagulant (and is probably a much safer anticoagulant than the pharmaceutical variety). Large amounts of vitamin E can interfere with vitamin K activity.

In some individuals with high blood pressure, beginning vitamin E supplementation may result in a temporary rise in blood pressure. Caution should be applied and blood pressure monitored while vitamin E levels are raised gradually.