Vitamin D Necessary for Healthy Bones

by Jennifer Wider, MD

(Washington DC, March 31, 2005 ): "Got milk?" Most women in the United States understood the message of the widespread and successful advertising campaign imploring them to increase calcium in their diets. But the message should have posed an additional question, "Got Vitamin D, too?"

Women over the age of 50 do not fully understand the role vitamin D plays in keeping their bones healthy, according to a national survey conducted by the Society for Women's Health Research, a nonprofit advocacy organization in Washington, D.C. What's more, more than half of those surveyed hadn't even discussed vitamin D with their doctors.

"Calcium, vitamin D and physical activity are three key elements in maintaining optimal bone health, especially for women over 50," said Jo Parrish, the Society's vice president for communications. While many women are aware of the need for calcium and exercise, a majority "simply do not associate vitamin D with bone health," Parrish explained.

Osteoporosis, a disease that weakens bones and increases the chances of fracture, affects more than eight million women in the United States. As women age, the risk of developing osteoporosis increases. During menopause, bone loss is hastened by the depletion of estrogen, placing women at high risk for developing the disease.

Vitamin D plays an important role in bone health because it helps the body absorb calcium from the diet. "The relationship between calcium absorption and vitamin D is similar to that of a locked door and a key; vitamin D is the key that unlocks the door and allows calcium to leave the intestine and enter the bloodstream," Parrish said. It also works in the kidneys, "to help absorb calcium that would otherwise be excreted."  This is the reason that most milk is fortified with Vitamin D.  The bad news is that most American women do not drink enough milk. 

In October 2004, the U.S. Surgeon General issued a report on bone health and osteoporosis for the first time. The report emphasized the importance of getting enough vitamin D to maintain good bone health. But most women are unaware of how to increase the amount of vitamin D in their diets.

"Many women erroneously assume that the foods they eat contain an adequate amount of vitamin D," Parrish said. But it's "almost impossible to get the required amount of vitamin D from foods."

Vitamin D is a fat-soluble vitamin found in a limited number of foods and can also be manufactured by the body after sun exposure. "Few foods in an otherwise healthy diet contain vitamin D," Parrish said, "with the exception of fortified milk, fortified orange juice, certain cereals and fatty fish such as salmon and sardines." For most people, a supplement is usually required to get the right amount in their diets.

The take home message - especially for women over the age of 50 - is to get enough vitamin D in their diets every day: "Women should talk to their health care providers about their need for vitamin D and how best to obtain it. Although it is not a routine test, women can ask for a test to determine their vitamin D level," Parrish said. "The surgeon general's report recommends that men and women over the age of 50 get 400 International Units (IU) of vitamin D per day, and that men and women over the age of 70 get 600 IU of vitamin D per day."

For more information on osteoporosis, click here.

© March 31, 2005 Society for Women's Health Research

The Society for Women's Health Research is the nation's only not-for-profit organization whose sole mission is to improve the health of women through research. Founded in 1990, the Society brought to national attention the need for the appropriate inclusion of women in major medical research studies and the resulting need for more information about conditions affecting women. The Society advocates increased funding for research on women's health, encourages the study of sex differences that may affect the prevention, diagnosis and treatment of disease, and promotes the inclusion of women in medical research studies. Dr. Donnica Moore has been a member of the Society since 1990 and is a past member of its Board of Directors.

Created: 3/31/2005  -  Donnica Moore, M.D.