New research reveals that vitamin D may play a more significant role in preventing certain kinds of cancer than previously suspected. Part of the steroid hormone family, which includes cortisol, estrogen, progesterone, and testosterone, vitamin D may be the most potent cancer prevention available today, says James E. Dowd, M.D., clinical associate professor of medicine at Michigan State University and author of The Vitamin D Cure (John Wiley and Sons, 2008).
WHAT IT PREVENTS: A 2008 study from Breast Journal involving women in 107 countries found that the incidence of breast cancer was about nine times higher in women who lived in areas with the least amount of sunlight (e.g., Iceland, England, New Zealand). Low vitamin D levels have also been associated with poor bone health, heart disease, colon cancer, diabetes (type 1 and type 2), depression, high blood pressure, arthritis, autoimmune disorders, and obesity.
GET TESTED: Some 60 percent of Americans are deficient in vitamin D, according to the Centers for Disease Control and Prevention. To find out if you're at risk, ask for the 25-hydroxy test, a simple blood test. Your level for optimal health should be above 35 ng/mL.
GET THE RIGHT DOSE: Current guidelines call for women ages 19 to 50 to get 200 IU daily, but experts recommend an extra 2,000 IU a day if you have some sun exposure (about 20 minutes a day), or more if you have little or no sun exposure. In winter, most people need 5,000 IU daily, says John Jacob Cannell, M.D., of the Vitamin D Council. Consider taking a supplement, but make it vitamin D3 (cholecalciferol, derived from animal products), which your body makes.
EAT YOUR VITAMIN D: Certain foods can boost your vitamin D intake. They include milk (100 IU per eight-ounce glass), cold-water fish (250 to 650 IU per 3.5-ounce serving), egg yolk (100 IU), and dried shiitake mushrooms (1,600 IU of D2 per 3.5-ounce serving).
GET SOME SUN: The Vitamin D Council recommends 15 minutes of daily direct midday sunlight. (Protect your face and hands with sunscreen, says Cannell.) Once you get your dose of natural light, apply sunscreen or get out of the sun.
The Basics of Vitamin D
ROLE: Significant in bone health, and reduces your risk of developing breast cancer, prostate cancer, colon cancer, diabetes, depression, high blood pressure, arthritis, autoimmune disorders, and obesity.
DOSAGE: Many experts suggest a minimum of 2,000 IU per day (through supplements), though current guidelines call for 200 IU daily for adult women.
SUN EXPOSURE: Your body uses sunshine to make vitamin D. Aim to get at least 15 to 20 minutes in the midday sun every day before applying sunscreen.