SAN FRANCISCO – Updated national guidelines on calcium and vitamin D intake should be followed only loosely, said Deborah E. Sellmeyer, MD, director of the Metabolic Bone Center at Johns Hopkins University, Baltimore, at a conference on osteoporosis, sponsored by the University of California, San Francisco. A lot of controversy has followed the Institute of Medicine's (IOM) November 2010 report “Dietary Reference Intakes for Calcium and Vitamin D,” which updated 1997 guidelines, Dr. Sellmeyer noted. She said she tailors the latest recommendations to meet the needs of individual patients. There is uncertainty about the cutoff level of serum vitamin D that's considered adequate and about the potential side effects from ingesting too much calcium, she said. The IOM recommends that adults take 600 IU/day through age 50 and 800 IU/day for those aged 51 years and older, with a suggested upper tolerability limit of 4,000 IU/day. Those are the intake amounts that generally would be needed to reach a serum level of 20 ng/mL. Many experts, however, think that physiologic and fracture data suggest that a “sufficient” serum level should be in the 30–32-ng/mL range, she said. “It takes most people about 1,200 IU/day to reach that” serum level, said Dr. Sellmeyer, who advises her patients to get 1,200 IU/day of vitamin D. The IOM recommends that men get 1,000 mg/day of calcium through age 70 years and 1,200 mg/day for those who are older. Adult women should get 1,000 mg/day through age 50 and 1,200 mg/day in older ages. The maximum tolerability limits were set at 2,500 mg/day for adults younger than 50 years or 2,000 mg/day for older adults. It's important to remember that the recommended level includes both dietary and supplemental sources of calcium, she emphasized. High doses of calcium increase the risk of developing kidney stones, studies show. The most controversial aspect of calcium supplementation in recent years has been some preliminary evidence of a possible increased risk for vascular calcification with higher doses of calcium. A randomized, controlled trial of 1,471 healthy women in 2008 found that the group taking 1 g/day of calcium citrate showed a doubling in risk for myocardial infarction (MI) and a trend toward higher risk of angina, compared with the placebo group (BMJ 2008;336:262-6). Another study by some of the same investigators “got a ton of press” even though it was a small meta-analysis, she added. The researchers looked at 190 trials of calcium supplementation but found only 15 eligible trials, and most of the data came from 5 trials. The meta-analysis reported a 31% increase in risk for MI in calcium supplement users, with possibly a higher risk in those taking more than 1,600 mg/day (BMJ 2010;341:c3691). “It's really hard to know at this point” whether the risk of vascular calcification from supplementation is significant, Dr. Sellmeyer said. “I think it does behoove us to be judicious with our calcium and not let people consume more calcium than we think is really beneficial.” Calcium citrate probably is a little better absorbed than calcium carbonate and may be a little less constipating, “but for a lot of people it doesn't matter,” she said. As always, physicians should be alert for conditions in their patients that might warrant higher intakes of calcium or vitamin D, she said, including malabsorption (as in patients who underwent gastric bypass surgery), healing osteomalacia, fracture healing, anabolic therapy, postoperative hyperparathyroidism, and hypoparathyroidism. Dr. Sellmeyer said she has no relevant conflicts of interest. Sherry Boschert is with the San Francisco bureau of Elsevier Global Medical News.