Late last year, a new health controversy grabbed the media spotlight: a report questioning the need for two supplements that have been longstanding nutritional touchstones for women past 40: calcium and vitamin D. We asked Naina Sinha, a member of the WVFC Medical Advisory Board and an endocrinologist specializing in metabolic bone diseases, to weigh in. Here’s her take on the topic.
On November 30th, the Institute of Medicine released guidelines about the intake of calcium and vitamin D. It is important to note that these guidelines were developed without the rigorous clinical research studies that are the gold standard in medicine. It is customary with medications that are being developed that studies are performed to closely examine safety, quality and efficacy prior to FDA approval. The FDA is not involved in regulation of supplements, and this is why, in this case, the research that is needed before making any sound recommendations is lacking.
To maintain healthy bones, we need enough calcium and vitamin D in our diet. The best way to get calcium is through food sources. Adults typically need 1200 to 1500 mg daily, which must be taken in three doses, as the body can only absorb 500-600 mg of calcium at a time.
In people with bone loss, it is especially important to get enough calcium every day, because if they don’t, the bone loss will be accelerated. If enough calcium can be absorbed through the diet, then no additional calcium supplements are needed. But it’s difficult to consume this much calcium on a daily basis, since it requires taking in a significant amount of dairy products. In these cases, a calcium supplement will be very beneficial to bone health. But it is important not to take too much calcium, as more than 2,000 mg a day can increase the risk of developing kidney stones. So it’s important to stay within the range of 1,200-1,500 mg per day.
Vitamin D is more difficult to get through diet than calcium is. It is mainly found in fatty fish like salmon, mackerel, and cod. We are able to make vitamin D in our skin upon exposure to sunlight, but if we’re wearing SPF and body lotions or if it’s wintertime, then the amount of vitamin D produced by the skin is far less. To get the daily dosage we need—roughly 800-2,000 units every day—a vitamin D supplement is needed. For people with bone loss, vitamin D is necessary to prevent further bone loss. Vitamin D can also help maintain good immune function and insulin function, which is especially important in people with diabetes. Vitamin D also plays a role in maintaining healthy mucosal surfaces. Just as with calcium, too much vitamin D can be harmful and can increase the risk of fractures and high blood calcium levels.
The new recommendations are better than the old ones (which recommended even less calcium and vitamin D). But it’s important that these guidelines serve as a launching pad for rigorous research studies. These must be performed to obtain the data that’s needed to make recommendations based in actual science. It is time the FDA got involved in evaluating supplements for the safety of us all.