Why You Need More Vitamin D

By Susan Male-Smith

“I drink a lot of milk, so I’m probably fine.” So says Boston resident Doug Bennett in response to all the recent attention given to vitamin D. But like most Americans with the same ho-hum reaction, he’s oh-so-wrong. Why? Milk and other foods don’t contain nearly enough vitamin D to meet most people’s needs, and while your body actually makes its own vitamin D from sunlight, people are spending more and more time indoors -- and when we do go out, we slather on sunscreen, which protects against skin cancer but also prevents vitamin D production. And now that we’re heading into winter ... well, you can see where this is heading.

Americans Don’t Get Enough Vitamin D
An alarming three out of four Americans are seriously short of vitamin D, according to the results of a recent study conducted at the University of Colorado. Moreover, a new study published in the September issue of Pediatrics reports that 70 percent of children don’t get enough D.

While today’s vitamin D shortfalls are less dramatic than the severe, rickets-producing deficiencies of the past, it’s far more insidious. Researchers have found that insufficient vitamin D has serious, far-reaching ramifications, including higher risk of cancer, heart disease, diabetes, respiratory infections (such as colds and flu), pregnancy complications, Parkinson’s disease, multiple sclerosis, arthritis and even dementia.

How Much Vitamin D Do You Need?
While the recommended dietary allowance (RDA) is still 400 international units (IU) of vitamin D per day, nearly every expert will tell you that’s simply not enough, and you can bet the RDA will change next year when a government panel weighs in. “Most Americans need at least 1,000 IU a day,” says Dr. Adit Ginde, a specialist on vitamin D and lead researcher of the University of Colorado study, “and many require even higher doses.” So to make sure you get enough of this essential nutrient:

Take a vitamin D supplement. Michael Holick, M.D., Ph.D., director of the Vitamin D Laboratory at Boston University, recommends 1,000 to 2,000 IU daily, especially in the fall, winter and spring. And don’t worry about getting too much; one study found that 10,000 IU a day is safe, even when taken for a year.
When buying supplements, be sure to look for D3 (cholecalciferol), which is much better absorbed than D2 (ergocalciferol).
Try to get 10 to 15 minutes of unprotected sun on your arms, neck and face every day. (The risk of harmful effects is small as long as you don’t overdo.)
Ask your doctor to check the 25-hydroxy vitamin D levels in your blood. For the most accurate results, get tested in the winter, when your D level is at its lowest. Aim for at least 30 ng/mL.

Vitamin D is the new “it” nutrient for a reason. Research shows it does so much more than we thought, at a time when we’re getting far less than we ever did. So enjoy your milk, take a D3 supplement, get some sun and have your D blood level checked. Your body will thank you.

Susan Male-Smith is a registered dietitian and freelance nutrition and health writer. She has written for Family Circle, Redbook, Child and American Health, and is a former editor of the Environmental Nutrition newsletter and co-author of Foods for Better Health, among other titles.

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