People with lower blood levels of vitamin D (less than or equal to 15 nanograms per milliliter, or ng/mL) had an increased risk of heart attack compared to people with higher levels, according to a study published in the June 9 issue of the Archives of Internal Medicine, which followed 18,225 men who were free from cardiovascular disease at the beginning of the study. The recommended daily amount of vitamin D for adults age 70 and older is 600 international units (IUs) daily. "These findings are suggestive," says Adam W. Grasso, MD, PhD, a staff cardiologist in the Department of Cardiovascular Medicine at Cleveland Clinic. "But it doesnt mean that low vitamin D levels caused the heart attacks." A second study, published in the June 23 issue of Archives, found that lower levels of vitamin D (between 7.6 and 13.3 ng/mL) were associated with both all-cause mortality and cardiovascular mortality in 3,258 men and women who were scheduled to have a coronary angiography.