For more than 30 years, vitamin E has been one of the most widely used supplements. It's been touted as a key antioxidant, helping to prevent heart disease, certain cancers and other serious illnesses. But two years ago, vitamin E became quite controversial, because a few studies showed that it could be harmful. So it left many people wondering, Is vitamin E safe? Is it effective? For what conditions? And what type of vitamin E should one use?
Vitamin E is found naturally in wheat germ, nuts, seeds, whole grains, egg yolks and leafy, green vegetables. Animal products are a poor source of vitamin E. The recommended dietary allowance for vitamin E is 15 mg, or approximately 22 international units (IU), per day. Serious vitamin E deficiency is rare, although many Americans don't get enough of the vitamin. People on low-fat diets are susceptible to low vitamin E levels, because fat is needed for absorption of vitamin E. And people with the genetic condition cystic fibrosis have trouble absorbing vitamin E.
Vitamin E has been shown to be important as a supplement for people with specific diseases, such as Alzheimer's and diabetes, and those with a high susceptibility to certain conditions, such as bladder cancer and eye disease. Vitamin E prevents LDL "bad" cholesterol from becoming oxidized (damaged), thereby helping to guard against plaque formation in the arteries, known as atherosclerosis. Also, low vitamin E levels are associated with an increased risk of major depression, rheumatoid arthritis and preeclampsia (a condition during pregnancy characterized by high blood pressure and swelling of the hands and face).
CONTROVERSIAL STUDIES
Two well-publicized studies have raised questions about vitamin E. The first was a meta-analysis (a study of other studies) led by researchers from the Johns Hopkins School of Medicine. The researchers reviewed 19 vitamin E studies that followed almost 135,000 patients. Most of these studies targeted populations at high risk for a chronic disease, usually coronary heart disease. Nine of the 19 studies focused on vitamin E alone, while the other 10 studies combined vitamin E with other vitamins or minerals. These studies ranged from 1.4 to 8.2 years in length. Vitamin E dosage varied from 16.5 IU to 2,000 IU per day, with a median dosage of 400 IU per day. The meta-analysis found that those taking 400 IU or more of vitamin E daily for at least one year were 10% more likely to die from all causes than those who took a smaller dose.
There are several problems with this analysis. First, researchers combined data that used both natural supplements (which provide the same type of vitamin E as that found in food) and synthetic forms of supplemental vitamin E. Previous research has shown that natural forms of vitamin E are better utilized by the body than cheaper, synthetic forms. The Cambridge Heart Antioxidant Study used only a natural form of vitamin E and found that a dose of at least 400 IU daily substantially reduced the rate of nonfatal heart attacks after one year of use.
The biggest criticism of the meta-analysis was that most of the studies included elderly people who had existing health problems such as cancer, Alzheimer's disease, heart disease and other potentially fatal illnesses. Even the authors of the study stated, "The generalizability of the findings to healthy adults is uncertain. Precise estimation of the threshold at which risk increases is difficult."
Another study, which was published in the Journal of the American Medical Association, focused on patients age 55 or older with vascular 130 disease or diabetes. The study concluded that for people with vascular disease or diabetes, long-term supplementation with natural vitamin E does not prevent cancer or cardiovascular events and may increase risk for heart failure. This study provides no evidence that vitamin E is unsafe for people who are healthy.
POSITIVE FINDINGS
Many studies exist that demonstrate both the safety and effectiveness of vitamin E (in natural and synthetic forms). A-few examples…
- A Harvard study of more than 80,000 healthy, female nurses ages 34 to 59 found a 47% reduction in the risk of heart disease in those who had taken daily vitamin E supplements of 100 IU or more for at least two years.
- A study of almost 40,000 male health professionals ages 40 to 75 found that those who took daily vitamin E supplements of at least 100 IU for more than two years experienced a 37o/o lower risk of heart disease.
- A National Institute of Aging study focusing on 11,000 people between the ages of 67 and 105 found that those who used vitamins C and E supplements in various dosages had a 53o/o reduction in mortality from heart disease and a 42% reduction in death from all causes, compared with nonusers.
- One study of moderate-severity Alzheimer's patients conducted at Columbia University in New York City showed that a very high daily dose of vitamin E (2,000IU) delayed the progression of Alzheimer's disease.
DIFFERENT TYPES
Vitamin E really refers to a family of compounds. There are more than 12 vitamin E compounds found in nature (currently eight forms are available in supplement form). There are two main groups of compounds—tocopherols (found in foods such as corn, soy and peanuts) and tocotrienols (found in rice, barley, rye and wheat). Many foods contain a blend of these two groups. Both have subgroups called alpha, beta, gamma and delta.
The most commonly used natural supplement form is alpha-tocopherol, and most studies have researched this form. But taking just alpha-tocopherol can reduce blood levels of gamma and delta-tocopherols, which is not beneficial. Epidemiological (population) studies indicate that higher blood gamma-tocopherol levels correspond to the reduction of prostate cancer and coronary heart disease. Also, delta- and gamma-tocotrienols reduce the liver's production of cholesterol. One of the positive aspects of the negative vitamin E studies I mentioned earlier is that they have pushed researchers to look deeper into what vitamin E supplements should really contain.
I spoke with Barrie Tan, PhD, president of American River Nutrition, Inc., and adjunct professor of food science at the University of Massachusetts, Amherst, who is a specialist in the production and supplementation of vitamin E. He explains that 70% of (dietary) vitamin E consumed by North Americans is the gamma-tocopherol form due to the abundance of soy and corn in our diets. He believes that vitamin E supplements used for disease prevention should be a blend of both tocopherols and tocotrienols. I agree with this view, because these forms are more similar to what we find in food.
One example of a full-spectrum vitamin E product that has a good ratio of tocopherols and tocotrienols is Now Foods' Tru-E BioComplex. To find a health-food store that sells this product, call 888-659-3663 or go to www.nowfoods.com. A good dosage for anyone, healthy or not, is 200 IU daily. Consult with your doctor before using dosages above 200 IU, especially if you are taking a blood-thinning medication, such as warfarin (Coumadin)—vitamin E can have a blood-thinning effect.
