Does extra calcium-which many people take to boost bone health- also protect against heart disease and death? Science continues to answer with a firm maybe, maybe not. A pair of new studies, however, suggest that while calcium supplements may not have such protective benefits, a diet rich in foods containing calcium might.In a review published in Annals of Internal Medicine, Howard D. Sesso, ScD, of Brigham and Womens Hospital in Boston and colleagues looked at 17 previous studies designed with other purposes in mind, in hopes of extracting fresh answers about prevention of cardiovascular disease. The existing evidence is quite sparse, they noted. The research they analyzed included both prospective studies and randomized clinical trials that focused on calcium supplementation, vitamin D supplementation, or both. All, however, included data on participants subsequent cardiovascular health.Sesso and colleagues concluded, Calcium supplements seem to have minimal cardiovascular effects. As other research has found, though, vitamin D may be a different story: Evidence from limited data suggests that vitamin D supplements at moderate to high doses may reduce cardiovascular disease risk, the researchers wrote.(Another review in that same journal, however, similarly screened 21 previous studies of vitamin D supplementation and concluded, The association between vitamin D status and cardiometabolic outcomes is uncertain. Trials showed no clinically significant effect of vitamin D supplementation at the dosages given.)Overall, researchers cautioned against taking calcium or vitamin D supplements specifically for cardiovascular disease prevention until more randomized clinical trials are completed. Any questions or concerns you may have about taking calcium, vitamin D or other supplements should be discussed with your personal physician,” Sesso added.Meanwhile, a new Swedish study of dietary, rather than supplemental, calcium intake reported that men with the highest consumption of calcium were 25% less likely to die of all causes. Alicja Wolk, MD, of the Karo – linska Institute and colleagues looked for associations of dietary calcium, as well as magnesium, with cardiovascular disease and death from cancer and all causes among 23,266 men, ages 45 to 79. Over almost 10 years, 2,358 of the men died.Researchers divided the men into three groups based on dietary calcium intake; none of the men used supplements. The group consuming the most calcium averaged 1,953 mg per day- nearly double the Daily Value (DV) of 1,000 mg-while the lowest-calcium group averaged 990 mg daily. When the highest group was compared with the lowest, dietary calcium was associated with a statistically significant lower rate of death from all causes and a nonsignificantly lower rate of cardiovascular disease. No similar link was found for dietary magnesium intake. The findings were published in the American Journal of Epidemiology.So, should you load up on foods high in calcium? Previous studies have suggested calcium might play a role in combating hypertension, although the evidence for such a benefit remains weak. Hopes that calcium might help prevent colorectal or prostate cancer have led to mixed results, and the new Swedish study failed to find an association with reduced cancer deaths.Its also possible to get too much of a good thing. Since kidney stones are commonly composed of calcium oxalate, might extra calcium encourage this excruciating condition? The National Institutes of Health (NIH) advises, For most individuals, other risk factors for kidney stones, such as high intakes of oxalates from food and low intakes of fluid, appear to play a bigger role than calcium.Excessively high levels of calcium in the blood can also impair kidney function, but this is usually caused by other health conditions rather than dietary or supplemental calcium intake. The Tolerable Upper Intake Level (UL) for calcium, set by the Institute of Medicine, is 2,500 mg daily.Until science produces more definitive answers, the best advice is to make sure youre getting enough calcium (1,000 mg/day, 1,200 mg after age 50)-preferably from your diet-and that its coupled with enough vitamin D to protect your bones (recent research suggests at least 800 IU/day). If theres any benefit from calcium against heart disease or death, consider it a bonus.TO LEARN MORE: Annals of Internal Medicine, March 2, 2010; abstract at www.annals.org/content/152/ 5/315.abstract. American Journal of Epidemiology, online before print; abstract at aje.oxfordjournals. org/cgi/content/abstract/kwp467v1. NIH Dietary Supplement Fact Sheet ods.od.nih.gov/factsheets/ calcium.asp
