July 15, 2003 -- Don't stop taking your vitamin C supplements just yet. They may help you stave off heart disease.
The data come from 85,118 healthy women studied since 1976 in The Nurses Health Study. Boston Children's Hospital researcher Stavroula K. Osganian, MD, and colleagues found that those women who took vitamin C supplements had lower risk of heart disease.
It's a modest effect. Use of vitamin C supplements lowered heart disease risk by 28%. But every little bit helps. Protection came from rather small doses of vitamin C -- up to about 700 mg per day, including dietary sources such as fruit juice. That's no megadose. But it's 10 times the current Recommended Daily Allowance for women.
The reduction in heart disease risk was seen in women that who took doses of vitamin C supplements greater than 400 mg per day.
"Modest amounts of vitamin C supplements may lower one's risk of coronary heart disease," Osganian says in a news release. "Our results do not support a role for megadoses of vitamin C."
Osganian and colleagues note that women who use vitamin C supplements might engage in other healthy behaviors that protect the heart. They therefore warn that their findings don't conclusively prove that vitamin C supplements cut a person's risk of heart disease.
In an editorial accompanying the study, Balz Frei, PhD, director of the Linus Pauling Institute at Oregon State University in Corvallis, makes an important point.
While it's still unclear whether vitamin C supplements have much of an effect, there's no doubt about how to prevent heart disease.
"What we know with certainty is that a healthy diet and lifestyle lowers the risk of coronary heart disease," Frei writes. "This is what we should advocate to [heart] patients and healthy people alike."
But, Frei adds, it can't hurt to take about 500 mg of vitamin C each day -- just for "health insurance."
The Osganian study, and Frei's commentary, appear in the July 16 issue of the Journal of the American College of Cardiology.