Vitamin D: So Much More than Bone Health
Here's one more reason to detest the gloom of winter: It zaps the body's natural supply of a vitamin linked to everything from bone health to cancer survival.
Loads of Americans aren't getting enough vitamin D, and those who live under frequently gray skies are hit harder. Studies have shown that as many as half of adults and four in 10 children in this country have too little of the nutrient in their bodies. The problem is even worse for African-Americans, Latinos and others with dark skin. Other high-risk groups include women of childbearing age, breast-fed infants who aren't receiving vitamin-D supplements and the elderly.
Doctors and scientists are becoming increasingly aware of the importance of the vitamin and the likelihood that patients aren't getting enough. The American Public Health Association recently issued a policy statement on the topic, calling for action by multiple federal agencies and by Congress.
"Vitamin D is much more than bone health," said Azzie Young, who wrote the statement and is president and chief executive officer of Mattapan Community Health Center in Boston. "It's linked to all kinds of chronic diseases diabetes, high blood pressure, muscle stiffness, most cancers, arthritis." The group wants to increase education of health professionals and the public, promote research involving diverse populations and add vitamin D to the list of nutrients that manufacturers must include on nutrition labels.
Vitamin D comes in the most bountiful dose from sunshine. When sun hits the skin, it triggers production of vitamin D in the body. Sunscreen impedes that process.
Experts most often recommend vitamin supplements, given concerns about harmful effects of sun exposure, the absence of sun in some parts of the world for days and weeks on end and the paltry amount found naturally in foods. The government recommends at least 200 international units of the vitamin a day for children and adults through age 50, 400 units for those ages 51 to 70 and 600 units for those older than 70.
In November, the American Academy of Pediatrics increased its recommendation for infants and children to 400 units a day, beginning soon after birth.
The Institute of Medicine is studying calcium and vitamin D and might adjust its recommendations, spokeswoman Christine Stencel said.
Many experts think that a daily dose of 1,000 units or more would be beneficial for everyone. Garden-variety multivitamins typically contain 400 units. "It's a public-health epidemic, and it's easy to treat," Young said.
"It's simple, it's effective, it's safe and it's relatively inexpensive."
Prices vary, but the cost of a 1,000-unit vitamin-D tablet is about 5 cents. Excess vitamin D rarely causes problems.
Dr. Elena Christofides, an endocrinologist with Endocrinology Associates in Columbus, is passionate about decreasing the incidence of vitamin-D deficiency and ardently recommends supplements to all her patients.
"This is one of the greatest public-health issues that's going to be facing us for some time," she said.
Dr. Velimir Matkovic, an Ohio State University Medical Center internist who specializes in bone disease, has studied vitamin D and found that Columbus residents, thanks to our cloudy skies, have severe deficiencies from November to April. Levels peak in July and August and begin to fall again after that, he said. Matkovic said it's safe to take up to 2,000 international units a day in supplements. He also advocates some sun exposure, although not during peak hours.
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