Vitamin D is for the Heart Vitamin D is for the Heart
Centers for Disease Control and Prevention

Many people know the human body needs vitamin D for strong bones. But a recent study suggests that the vitamin is also good for a strong heart. The research, published in the May 2007 issue of Archives of Internal Medicine, hints that taking vitamin D supplements could have a positive impact on people’s health—but a single recommended dose might not necessarily be a good fit for everyone.

Several earlier studies revealed high rates of hypertension and diabetes, two risk factors for cardiovascular disease, among people with low amounts of vitamin D in their blood. But these studies were conducted in small groups of people or in groups that were not representative of the general population.

To address this weakness, Keith Norris and colleagues at Charles R. Drew University of Medicine and Science and associated collaborators analyzed data from the Centers for Disease Control and Prevention’s Third National Health and Nutrition Examination Survey (NHANES), which combined interviews with physical examinations. The survey sample of more than 15,000 participants included sufficiently large numbers of individuals aged 60 years and older, African Americans, and Mexican Americans to more precisely estimate the prevalence of different conditions in these groups.

Research by Keith Norris and colleagues at Charles R. Drew University of Medicine and Science suggests that current recommended doses for vitamin D supplements, based on the amounts necessary to maintain strong bones, are inadequate. Higher amounts of the vitamin could be needed to protect some people from cardiovascular disease. Photo courtesy of
Norris, who heads the Comprehensive Center on Health Disparities in Chronic Kidney Disease at Charles R. Drew University, a center supported by NCRR’s Research Centers in Minority Institutions (RCMI) program, found that many people have low levels of vitamin D, particularly women, the elderly, and racial and ethnic minorities. The lowest amounts of vitamin D were found in people with hypertension, obesity, diabetes, and high triglyceride levels—even after adjusting for many other factors—suggesting that vitamin D deficiency contributes to these cardiovascular disease risk factors.

Although vitamin D deficiency is not the only cause of these conditions, it is easy to treat. “Even if it’s half or a third as good as other treatments, but much cheaper, taking a vitamin supplement becomes an important therapy, particularly for minority communities in which people are apprehensive of the medical system,” explains Norris.

The study also suggests that the recommended intake of vitamin D, based solely on the levels needed to maintain strong bones, might be inadequate for preventing heart disease. Recommendations might need to be adjusted particularly for the elderly, women, and minorities, who typically have smaller amounts of this vitamin than other groups.

The finding points to the importance of including diverse populations in clinical research. “If the evidence is there for Caucasians, we usually say it’s okay for other racial and ethnic groups. If it’s there for men, we say it’s okay for women,” says Norris. “That’s not always true.”