Vitamin E (Alpha-tocopherol).
Vitamin E is an essential fat-soluble coenzyme and exists in eight  different chemical forms with similar properties. Four tocopherols and equivalent number of tocotrienols are included in this group. Alpha-tocopherol is the most active form in humans. Thus, the terms "vitamin E" and "alpha-tocopherol" will be used as synonyms in this page.
Vitamin E is an important antioxidant and acting in synergy with vitamin A and vitamin C and other antioxidants, such as coenzyme Q10, selenium and riboflavin can neutralize free radicals which are unstable and harmful by-products of metabolism. As it happens with vitamin A, after alpha-tocopherol is used, its antioxidant capability is restored by the vitamin C action.
As an antioxidant, vitamin E seems to prevent cancer either by protecting the cell membrane from the harmful action of free radicals or by repairing the DNA or by enhancing the efficacy of the immune system.
Vitamin E is considered anti-ageing factor and contributes to the formation of red blood cells and the utilization of vitamin K.
Alpha-tocopherol can prevent atherosclerosis, excessive platelet production and blood clotting within the vessels. It can also increase HDL (good cholesterol) blood level, promote the enzymatic breakdown of existing clots and enhance sensitivity of the cells to insulin. Despite the above properties, the role of alpha-tocopherol in prevention of coronary heart disease or stroke has not been acknowledged by all specialists yet. Studies have given evidence that vitamin E can protect from cardiovascular disease but the degree of this protection is an ambiguous issue. According to a number of researchers, alpha-tocopherol provides a significant benefit, whereas others have not been convinced yet and require further investigation.
Sources of vitamin E (alpha-tocopherol).
Vitamin E is contained in wheat germ, sunflower seeds and oil, olive oil, olives, safflower oil, corn, nuts, hazelnuts, almonds, asparagus, vegetable oils, peanut butter, margarine, fortified cereals, spinach and other green leafy vegetables.
Supplements of vitamin E (alpha-tocopherol).
Quite often the amount of alpha-tocopherol obtained from dietary sources is not adequate. This happens, when people eat limited quantities of the above foods, since the majority of them are of high caloric value and can lead to weight gain. Food supplements with vitamin E are a reliable alternative option, providing they are used properly and the recommended dose is not exceeded.
Vitamin E supplements may contain either the natural or the synthetic form of the vitamin. The latest is described as d, l-alpha-tocopheryl and it is half as active as the natural form which is referred to d-alpha-tocopheryl.
The recommended dietary allowance (RDA) of 15mg or 16.5 IU per day seems to be adequate for healthy adults. Vitamin E supplements may be required in people who suffer from fat malabsorption due to certain conditions, such as biliary impaired excretion, cystic fibrosis and Crohn's disease. Moreover, it has been estimated that the average daily intake of alpha-tocopherol in the USA is 6mg and 9mg for females and males respectively. These figures are well bellow the RDA and indicate that some reasonable supplementation may be beneficial. Try the following  button, if you want to find vitamin E food supplements online. Products containing only d-alpha-tocopherol are recommended, since any other form of the nutrient is not very active in humans.
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Deficiency and toxicity of vitamin E (alpha-tocopherol).
In humans, vitamin E deficiency is quite rare and can happen in people who suffer severe malnutrition, disorders of fat absorption and metabolism. Zinc deficiency may lead to low levels of alpha-tocopherol.
Vitamin E deficiency is usually characterized by neurological complications. These may be peripheral neuropathy, impaired coordination and balance, neuromuscular problems and eye conditions, such as retinopathy. A physician must determine, whether they are the result of a vitamin E deficiency or they are caused by other conditions. According to the Linus Pauling Institute, alpha-tocopherol deficiency may be associated with a wide range of illnesses, such as cataract, heart disease, lung problems and liver damage.
As a fat-soluble nutrient, vitamin E can accumulate within the body and may cause toxic symptoms, in excessive dosages. Alpha-tocopherol is considered as a strong anticoagulant and the most important side-effect is the increased risk for automatic internal or uncontrollable external hemorrhages, due to impaired ability of blood clotting. Other side-effects have not been identified yet.
Recommendations for vitamin E (alpha-tocopherol).
The vitamin E recommended dietary allowance (RDA) is 6-7mg/day or 9-10.5 IU/day, for children, and 15mg/day or 16.5 IU/day for adults, including pregnant women. The relevant daily doses for nursing mothers are 19mg or 28.5 IU. The above figures seem to be adequate for optimum health. Since in the USA and Europe the average intake of vitamin E seems to be adequate, only some moderate supplementation may be needed. It has to be mentioned that the Food and Nutrition Board of the Institute of Medicine has set the tolerable upper intake level (UL) for vitamin E at 1,000mg or 1,500 IU per day. However, in November 2004 the American Heart Association stated that vitamin E doses of 400 IU per day or higher may be dangerous.
In general, if supplements of 400 IU d-alpha-tocopheryl are used, one tablet per week seems to be safe and adequate.
People, who are under warfarin medication or they are deficient to vitamin K, should not take any vitamin E supplementation, unless they have been advised otherwise by their healthcare provider. |
