The basic characteristic of vitamin E is that it acts as an antioxidant in our body. It is solvable in fats, which is why it acts as a protector of fatty structures in our body. According to the recent research, it appears that vitamin E prevents cancer, heart disease, and complications of diabetes.
It is necessary for keeping our immune systems strong and protecting the thymus and white blood cells from oxidation. The eye also needs vitamin E for the proper development of the retina, and, at the same time, it protects the eye form cataract and macular degeneration. This vitamin is of crucial importance for the normal functioning of our sex glands, and it is also important for a proper muscle functioning and the integrity of our central nervous system.
Vitamin E deficit is very rare and it occurs mostly in persons with chronic liver diseases, affecting the improper absorption of fats. Deficits can also be caused by an extreme restriction of fats in the diet, since it is necessary to consume a sufficient amount of fat for a proper absorption of vitamin E. The so-called, sub-clinical vitamin E deficit is much more recurring, and it is related to an increased risk of cardiovascular disease and cancer.
About the chemical structure
The chemical name for vitamin E is tocopherol. The names of all types of vitamin E start with a “d” or “dl”, which are the markers for the different chemical structures. The “d” form is natural, while the “dl” form is the synthetic one. Vitamin E’s natural form is more active than the synthetic one. With the purpose of compensating for its low activity levels, a higher dosage of the synthetic vitamin E is added. The toxicity of the synthetic vitamin E has not been proven, but the intake of the vitamin E’s natural form is recommended.
The different forms of vitamin E are also referred to “tocopherol” or “tocopheryl” (“tocopheryl acetate”). These two forms are not significantly different, even though tocopherol absorbs a little bit better, while the tocopheryl form has a longer shelf life. Both forms are active during the oral intake, but the skin cannot use the tocopheryl form, which should, therefore, be used through the external application of vitamin E on the skin.
Daily needs and sources
The recommended daily dosage of vitamin E is 15 mg in the alpha form – tocopherol. However, the dosages used in many scientific studies are significantly higher – 200 to 800 IU (international unit). The upper limit of the allowed daily intake of vitamin E is 1000 milligrams. Since it is almost impossible to achieve the intake of vitamin E in the amounts used for therapeutic purposes, people often turn to vitamin E food supplements.
The daily dosage of vitamin E depends on the intake of polyunsaturated fatty acids in the diet (they originate from oily fish, seeds, and nuts). The more of these fats there are in the diet, the greater risk that their structure will be damaged by the free radical exists, which is why we need vitamin E to prevent the free radicals’ harmful activity on fatty acids. The optimal ratio of vitamin E and polyunsaturated fatty acids is 0.4.
The best dietary sources of vitamin E are wheat germ oil, nuts, seeds, herbal oils, egg yolk, and leafy green vegetables. High, therapeutic dosages of vitamin E (above 100 I.U.) cannot be compensated with food.
The toxicity of vitamin E is very rare. Extremely high dosages of vitamin E can interfere with the usage of other vitamins that dissolve in fats. Even so, persons treated with anticoagulants must be careful when taking the increased dosages of vitamin E, which is why they have to inform their physician about all of the food supplements they are taking.
What does the science say?
In spite of the extremely attractive theoretical base about the oxidative stress and the effects of antioxidants, the studies that have been conducted on people are not giving the desired results. A meta-analysis about the connection between the vitamin E and mortality rate at people who are taking it, published in 2005, has raised a lot of dust not only in the scientific circles but also in the wider public. The authors of this meta-analysis have compared the results based upon 19 random, placebo-controlled studies. The dosages used in the studies varied from 16.5 IU to 2000 IU on daily basis.
The conclusion of the above-mentioned meta-analysis states that the daily intake of vitamin E in the dosage of 400 IU and higher within the course of one year can increase the risk of premature death. The studies in which the low dosages of vitamin E were used have mostly shown the beneficial effect of this vitamin. The conclusion that follows from this meta-analysis is that digesting vitamin E in dosages higher than 400 IU should be avoided and that the recommendations about its upper limit intake in the dosages that exceed 1000 mg should be revised.
Nonetheless, not everyone shares the same opinion and many people object the controversial meta-analysis. The main objection is that the participants of these studies, who have been digesting extremely high amounts of vitamin E, were mostly older persons and persons who suffered from chronic diseases.