Reprinted from the Health District's quarterly publication mailed to district residents (Spring 2007)

To build good strong bones, we need not only calcium but vitamin D to help the body absorb and use the mineral. Now, research suggests we need more vitamin D and for a whole separate health benefit.

Drastically raising vitamin D levels may prevent up to half of all breast cancer and two-thirds of colorectal cancer cases in the United States, researchers said in a study published in January. The study’s authors wasted no time in urging adults to get 1,000-2,000 international units (IU) a day of vitamin D. That’s in sharp contrast to the U.S. government’s recommendations: 200 IU for those age 50 and younger, 400 IU for ages 51-70, and 600 IU for ages 71 and older.

For years, studies have linked low amounts of vitamin D with muscle weakness and its accompanying complication: falls in the elderly.

Earlier studies also praised vitamin D’s role in helping protect against heart disease and autoimmune disorders, such as multiple sclerosis, and type 1 diabetes.

The body gets vitamin D in a handful of ways. Our skin produces it when exposed to sun, hence its nickname, “sunshine vitamin.” The problem with making the vitamin by taking in rays is that most people, particularly at northern latitudes like here, don’t get enough sun exposure in the winter to make the amount needed. And sunscreen, which protects against skin cancer, blocks the making of vitamin D.

While food is typically the best source for getting the nutrients we need, getting vitamin D from what we eat is challenging if not impossible.

“We just don’t have many dietary sources of vitamin D,” says Dianne Moeller, a registered dietitian at the Health District. “You can find it in small amounts in fortified milk, fish, liver and egg yolks.”

Daily supplements, in the form of vitamin D3 (cholecalciferol), can help us get what nature can’t adequately provide, she says.

Getting more than 800 mg of calcium a day may be unnecessary as long as vitamin D levels in the blood are normal, a 2005 study published in the Journal of the American Medical Association found.

“Without adequate vitamin D, your body can’t use the calcium,” Moeller says.

How much vitamin D the body produces depends on age, sun exposure (including latitude, clothing and sunscreen use), skin color and obesity.

With age, the body has a harder time making vitamin D. Skin pigment, or color, matters, too, when it comes to making vitamin D from sunlight, putting darker-skinned people more at risk for missing out on this critical vitamin. Because the vitamin is stored in body fat, obese people have less of it available for use by other tissues in the body.

So, what’s the best way to boost the vitamin D you need without increasing your risk for skin cancer?

For most people, experts say, it means striking a daily balance of catching a few rays (10-15 minutes’ worth without sunscreen) when possible and taking 1,000-2,000 IU of vitamin D3 supplements.

“Supplementation and small amounts of sun exposure are the preferred methods of obtaining vitamin D,” says a consensus statement from the American Cancer Society and other health groups in May 2006. “If you are concerned about adequate vitamin D levels, discuss supplementation with your health care practitioner.”