Vitamin Controversy - Brief Article

Vegetarian Times, June, 2000 by Abigail Chipley

Always hungry for a sensational story, newspapers and magazines across the country were quick to pick up on the results of an unpublished study presented at an American Heart Association conference last March. The headline-grabbing conclusion of the researchers: Vitamin C, a supplement widely used by Americans, could increase the risk of heart disease.

In the study, researchers from the University of California, Los Angeles, measured the thickness of a neck artery wall in 573 healthy people. After one year, participants who had taken just 480 milligrams (mg.) of vitamin C daily had an increase in thickness almost three times greater than those who hadn't swallowed supplements. Since thickened artery walls lead to narrower and less elastic blood vessels, the researchers theorized that vitamin C supplements could increase the risk for both heart disease and stroke.

But before you toss your vitamins, it's important to evaluate the findings in their proper context. Literally hundreds of studies have reached a very different conclusion about the link between vitamin C and heart disease. In fact, a 1995 study of more than 11,000 people that used the same research methods as the California investigators, produced the exact opposite effect: Participants taking 1,000 mg. of vitamin C experienced a significant reduction in artery wall thickness. And more than 20 clinical studies published since 1996 in Circulation, the premier journal of heart disease research, have found that vitamin C helps to maintain artery flexibility. "No other published paper has ever shown an adverse effect of such a low dose of vitamin C as did the University of California study," says Jeffrey Blumberg, Ph.D., a Tufts University nutrition professor. "Even if it was well executed and well interpreted, I don't think any consumer should make a decision based on a single study."

Furthermore, though most of the press failed to point this out, the study wasn't peer-reviewed before being released to the public. On top of that, it was an epidemiological, or observational, study not a more rigorous double-blind, placebo-controlled clinical trial. "At best these types of studies can give you a hypothesis. They can never show direct cause and effect," comments Balz Frei, Ph.D., of the Linus Pauling Institute at Oregon State University in Corvallis. Even the primary researcher, James Dwyer, Ph.D., acknowledged that his research was preliminary. "It's important to see if my findings can be replicated in other studies," he says.

Despite overwhelming evidence that vitamin C is a heart-healthy supplement, the American Heart Association still doesn't officially recommend vitamin supplements. And while it is certainly possible to get adequate amounts from fruits and vegetables, many Americans may fall short. Says Blumberg, "I would advise people to continue taking their vitamins. There's a lot of evidence out there that taking vitamin C is safe and even beneficial."