Edited by Kate Findley and proofread by Angela Shoemaker, The Great Courses Daily
Over the years, vitamin E has been offered as a cure for everything from impotence to grey hair to heart disease. Professor Anding helps you sift through the hype to arrive at the truth.
History of Vitamin E
When exploring the roles of vitamin E, understand that it is a fat-soluble vitamin, which means about 90% of your body’s vitamin E is going to be stored in body fat. It was first discovered in 1922, when the deficiency of the vitamin led to sterility in rats.
Keep in mind that the history of nutrition in the United States is relatively new. Since that finding, early recommendations for vitamin E were as an aphrodisiac.
There’s a difference between infertility and sexual desire, so this was a common but misguided connection. Vitamin E was also promoted for anything anti-aging including grey hair, wrinkles, and impotence.
Vitamin E Roles
The primary role of vitamin E is as an antioxidant. An antioxidant stabilizes cell membranes and prevents them from oxidation (combining chemically with oxygen, which damages DNA and proteins), thus protecting the cellular integrity of that cell membrane.
Vitamin E is thought to protect lung membranes from environmental contaminants such as air pollution, DNA from being altered or mutated, and against cardiovascular disease by protecting lipids (fats) from being oxidized. Often, oxidized low-density lipoproteins (LDL) cholesterol plays a key role in the development of heart disease.
Vitamin E is not a compound. It actually belongs to a family of compounds known as tocopherols, with eight different forms. According to Professor Anding, this is an important concept because form determines function and in this case, bioavailability.
Forms and Bioavailability
In vitamin E studies that don’t describe the form, we need to ask ourselves whether the information will be true for all forms of vitamin E. The most common form of vitamin E found in food and supplements is alpha-tocopherol.
Vitamin E can exist as two different isomers—the way that molecule is configured in space. The synthetic form is “dl” while its natural food-based form is known as the “d-isomer.”
The bioavailability of the synthetic version is about half of the natural version. Bioavailability is a key component in human nutrition as it determines how much of the vitamin your body can actually use.
A Cure for Heart Disease?
As a consumer, the science of vitamin E can be challenging to keep up with. One day vitamin E is good for you; the next day, it isn’t. As a whole, nutrition science continues to emerge, so what’s true today will be critiqued five years from now to determine whether or not it still holds scientific merit.
Interest in vitamin E was generated when observational and sometimes epidemiological studies suggested that vitamin E might lower the risk of heart disease. One of the most convincing studies was published in 1993 as part of the overall National Nurses Health study in the United States.
It suggested that women who took vitamin E for more than two years had a 30% to 40% risk reduction for cardiovascular disease. In the nutrition community, this study got scientists’ attention.
“We have a dietary solution to cardiovascular disease, and, oh, by the way, it comes in a pill,” Professor Anding said.
At that time, international studies also suggested that vitamin E was associated with a heart disease risk. Thus, it wasn’t just the research in the United States that made this claim; it was worldwide studies.
Scientists began to explore whether these results applied to the long-term and also took a look at side effects and form. This led to the HOPE Study, which is where optimism about the benefits of vitamin E began to fade.
HOPE stands for Heart Outcomes Prevention Evaluation. It was a long-term study evaluating, in part, the effectiveness of vitamin E.
This subset of individuals had preexisting vascular disease or diabetes and thus were already on their way to developing heart disease. The study was unique as it followed individuals for up to seven years.
Participants took 400 International Units of vitamin E, which is more than the standard required dosage. Not only did the study find no benefit when it came to using vitamin E for the prevention of heart disease or cancer for high-risk individuals, but it also found that individuals taking vitamin E had increased risk of heart failure.
For all its promise in the early 1900s, and up into the 1990s, vitamin E eventually failed to deliver upon its reputation as a wonder drug.
Professor Roberta H. Anding is a registered dietitian and Director of Sports Nutrition and a clinical dietitian at Baylor College of Medicine and Texas Children’s Hospital. She also teaches and lectures in the Baylor College of Medicine’s Department of Pediatrics, Section of Adolescent Medicine and Sports Medicine, and in the Department of Kinesiology at Rice University.