Vitamin D might actually help you live longer, but odds are you're not getting nearly enough
You're taking cover under hats and wearing sunscreen to protect yourself from
skin cancer. But it turns out that those precautions might also be contributing to vitamin D deficiency. Up to 36 percent of Americans
are low on the nutrient, recent research suggests, and that increases the risk of weak bones, certain cancers, and more. Vitamin
D is the only nutrient your body makes itself, but you can't make it without the sun's help. So is the answer to get out and
catch some more rays? Probably not. Instead, look at your diet and consider taking supplements.
"We are coming to recognize that even in sunny places like Texas there is evidence of widespread D deficiency," says Irwin
Rosenberg, M.D., director of the Nutrition and Neurocognition Laboratory at Tufts University. Quest Diagnostics, a leading
lab, reports that the demand for vitamin D tests increased by about 80 percent last year. But is it worth it to shell out
$200 for a blood test? And how much vitamin D do you really need? Here's what some of the latest studies and experts had to
say.
How much is enough?The level of vitamin D associated with the
health benefits listed here is higher than the government's recommended level of 400 international units. For adults, our experts recommend 800 to 1,000
IU daily, which is hard to get without popping a pill. "As one who tends to be very conservative about supplements," Rosenberg
says, "this is one that I recommend to half of my patients." Multivitamins and calcium supplements usually contain 400 IU
of vitamin D, or you can buy vitamin D supplements. But there's no reason for most people to exceed the government's safe
upper limit of 2,000 IU. So don't overdo it.
The best way to get any nutrient is through food, though there aren't a lot of
sources of vitamin D, and sunlight can be a less-than-reliable source. Experts say spending time in the sun can help, but your body's ability
to produce vitamin D can also hinge on whether you live in a sunny climate. Being older, heavier, or having dark skin can
also limit the sun's effects.
Using tanning salons is downright dangerous. Ultraviolet radiation, including exposure from tanning beds, is linked to most
of the 1.5 million skin cancers and the 8,000 melanoma deaths in the U.S. each year. "The difficulty and the challenge for
research is to identify the dose of sun exposure that gives you adequate D without increasing your risk of skin cancer," says
Patsy Brannon, Ph.D., R.D., professor of nutritional science at Cornell University. "Right now, we just don't know where to
draw that line."
Should you be tested?Reliable tests have only recently become available, and our experts say it's too soon to recommend routine screening for everyone.
But testing is a good idea if you have conditions linked to abnormal calcium metabolism or vitamin D deficiency, such as osteoporosis,
hyperthyroidism, and possibly multiple sclerosis. Testing might also make sense if your risk is higher due to your age, where
you live, your skin color, or your weight. But unless you have a medical condition specifically linked to deficiency, insurance
probably won't pick up the tab.
This article first appeared in the December 2008/January 2009 issue of ShopSmart.