Is Your Vitamin D Deficient?

If you (wisely) take a vitamin D supplement, you may not be getting enough D for your dollar.
At ConsumerLab.com, an organization that conducts independent evaluations of health and nutrition products, researchers tested 28 popular vitamin D supplements for purity and label accuracy. Many failed.
“Twenty-nine percent of the products we evaluated had one or more quality problems,” says Tod Cooperman, M.D., president of ConsumerLab.com.
The most common issue? Not enough vitamin D. One supplement contained just 31 percent of the vitamin D amount advertised on its packaging. Other supplements were contaminated with lead!
“If they’re following good manufacturing practices, they shouldn’t be making mistakes like this,” Cooperman said of the companies who made the faulty products.
Based on the results of the tests, the store-brand vitamin D3 supplements sold at GNC, Rite Aid, and the Vitamin Shoppe had a correct dose of D and weren’t contaminated. To see the full report—which lists exactly which brands had problems—you’ll need to get a membership for ConsumerLab.com ($2.50/month for 1 year) or pay $12 for one-time access. (We tried sweet-talking them into letting us publicize the complete results, but no dice.)

Do You Really Need a Supplement?
Sure, no company should shortchange its customers. But the results from ConsumerLab.com are especially aggravating considering that at least 50 percent of men are D deficient—meaning that many guys need to take a supplement to get enough—says James Dowd, M.D., CEO of the Arthritis Institute of Michigan and author of The Vitamin D Cure.
You can produce vitamin D from (free) sunlight; just 15 minutes of sun exposure on bare arms and legs three days a week could help your body produce all the vitamin D it needs, according to a Harvard Medical School report. But you’re probably not getting enough vitamin D from sun exposure alone, explained Dowd, depending on the time of day, the amount of cloud cover, your skin type, and other factors—making a vitamin D supplement a good way to make up the difference. Some foods, such as salmon and milk, contain modest amounts of vitamin D.

What to Take
Dowd recommends taking a supplement with D3, or animal-sourced vitamin D, which is up to five times more potent than plant-sourced vitamin D2. He advises his patients to take 20 IU of vitamin D3 per pound of body weight each day. (Dowd said the Institute of Medicine’s recommended daily allowance of 600 international units (IU) of vitamin D is too conservative, and many experts agree.) Try GNC Vitamin D-3, 1000 mg ($9.99 for 180).
Why care about D in the first place? It’s essential to bone and muscle health, and has been shown to lower the risk of certain cancers, heart disease, autoimmune diseases, and infections, explains Edward Giovannucci, M.D., a professor of nutrition at Harvard’s school of public health. It could even treat type 2 diabetes, new research suggests.