Too Much Vitamin E Not Good For You?
~ October 2004 No.186 ~
The guiding principle of functional foods and nutraceuticals is that the traditional views of how much of a particular nutrient should be consumed may be too low. By consuming more you get added protective effects.
It was not too long ago that it was generally felt that the science of human nutrition had come to an end. All of the essential nutrients (vitamins, minerals, fats, protein, carbohydrates) had been described, and in most cases recommended daily intakes had been defined. All you had to do was make sure that you had a diet that satisfied all of the daily requirements and you would be healthy. However, it must be remembered that the daily requirements were set to allow for maximum growth and to prevent deficiency conditions.
Foods that we eat contain more than just nutrients to help us grow. In some cases it is believed that if certain nutrients were consumed at levels above the traditional requirements, additional health benefits and disease resistance can occur. Thus the field of functional foods was born. In many cases the mechanism of protection was not understood. The relationships between particular nutrients and their function in the body are still not well understood.
The argument to increase vitamin E went as follows. The chemical structure of vitamin E shows that it is an antioxidant, and it had been shown that in the body vitamin E does act as an antioxidant. Oxidative damage to tissues and cells can alter cellular metabolism and function, and can lead to cell death, cancer and cardiovascular problems. Therefore, it was concluded that consuming high levels of vitamin E - higher than the recommended daily intakes - should protect against many diseases.
Many people now include a vitamin E supplement as part of their ACE (vitamin A,C, E) regime. Capsules of vitamin E with 100, 300 and 400 IU are on the market. However, recent findings indicate that high levels of vitamin E may be, in fact, bad for you
At a recent meeting of the American Heart Association (2004) researchers presented data that showed high levels of vitamin E may cause death. A statistical analysis combining data from studies involving 136,000 indicated that subjects receiving high doses of vitamin E had a 5% increase in death. The cause of death in these studies was not reported.
The release of this report has caused a great deal of debate in nutrition and health circles. The biggest question relates to the form of vitamin E used in the studies. In many cases, supplements do not contain the natural form of vitamin E R,R,R- a -tocopherol, and so their effects in the body may be different from the vitamin E found in foods. Further analyses will have to be done to ensure the safety of high levels of vitamin E.
Chemical Structure of alpha-tocopherol
High-Dosage Vitamin E Supplementation May Increase All-Cause Mortality
Ann Intern Med. 2005,142:37-46