Doctor's Diagnosis: Vitamin D

VITAMIN D

My wife of over 20 years was not happy when she played back the message the doctor had left on the answering machine: “You need to take vitamin D and calcium and do more weight-bearing exercise.” Being a business executive and not a health-care worker, she turned to me for an explanation.

Like an ever-increasing number of patients, she had undergone a bone-density test to assess the health of her bones, and it showed she had an early form of osteoporosis. Her bones were not as strong as they should be, and she was at increased risk of experiencing fractures.

As we age, we are all at risk for osteoporosis, but people who are inactive, smoke, drink too much or take certain medications are especially likely to develop this problem.

Calcium is a mineral that helps give bones their strength, but calcium is only useful in the presence of vitamin D. This vitamin actually functions as a hormone, acting on cells throughout the body. Its most important effects are increasing the absorption of calcium from the intestines and helping to make sure the calcium is available for the bones to use.

Vitamin D can be found naturally in some foods, such as oily fish, and in fortified foods such as milk, bread and cereals. Even so, most people consume an insufficient amount of the vitamin. Interestingly, a main source of vitamin D is your skin. When exposed to sunlight, your skin can make a vitamin D precursor that, after being modified by the liver and kidneys, becomes active. The problem is that many variables affect how much vitamin D your skin can generate: your type of skin pigmentation, time spent in the sun, the latitude you live at and use of sunscreen are some examples. Needless to say, if you’ve spent this winter on Long Island, your skin has not generated much vitamin D.

For the calcium and vitamin D to really strengthen my wife’s bones, she has to do more weight- bearing exercises. Her main form of exercise is swimming, which, like bicycle riding is a great exercise but does not put enough stress on the bones to be helpful for this problem. Brisk walking, jogging, resistance training or tennis would be much more effective at strengthening her bones.

Persuading my wife to take calcium and vitamin D pills was relatively easy; having her increase her weight bearing exercises is proving to be a whole lot more challenging.

Dr. Stephen Picca of Massapequa is Board Certified in both Internal Medicine and Anesthesiology. He is retired from practice. Questions and comments can be sent to Dr. Picca at health@newsday.com.