What Some Experts Think
The federal government is very picky when it comes to making a link between any product--whether it’s a food item, drug or dietary supplement--and the treatment and prevention of disease.
Strong scientific evidence is needed before approval is given to make such a claim. Many health experts believe that such evidence is mounting for three dietary supplements: selenium, folic acid and vitamin E. Just what will it take for the U.S. Food and Drug Administration to approve a claim that these nutrients help in the treatment or prevention of disease? Some experts give their views:
Selenium and cancer prevention
Gerald Combs Jr., professor of nutrition at Cornell University who has researched the role of selenium on reducing cancer risk.
What is known: A 1996 article in the Journal of the American Medical Assn. showed that selenium supplements reduce the incidence of some types of cancer by as much as 67%.
What is needed: The JAMA study looked only at white men. Does the supplement work in other ethnic groups and in women on hormone-related cancers? What is the most effective dose?
Prediction: “It’s clear that selenium can reduce cancer. The question is whether that [link] is predictable. We need more clinical trials to substantiate what we found. My guess is that another positive clinical study would be hugely compelling.”
Vitamin E and reduction of heart disease
Dr. Ishwarlal Jialal, researcher on vitamin E at the University of Texas Southwestern Medical Center.
What is known: Epidemiological studies show that low vitamin E intake in a population is linked to greater death rates from heart disease.
What is needed: A large, randomized intervention trial.
Prediction: “I think the totality of evidence supports vitamin E supplementation for patients with coronary disease. In prevention [of heart disease] I think we need a clinical trial.”
Folic acid and reduction of heart disease
Dr. M. Rene Malinow, researcher at the Oregon Health Sciences University on the effects of folic acid to reduce homocysteine levels in the blood, thus reducing the risk of heart disease.
What is known: High homocysteine levels are associated with a higher risk of heart attack and stroke. Folic acid supplements lower homocysteine levels.
What is needed: Do other nutrients or multivitamins also lower homocysteine levels?
Prediction: “The time is right for a clinical trial on multivitamins to see if multis prevent heart disease.”
