Winters are difficult for many of my patients, as heavy snow can clog the streets for weeks at a time, the sun seems to vanish for long periods as well, and temperatures frequently sink below zero degrees Fahrenheit.
Even after spring arrives, many people still find themselves feeling under the weather—for good reason. During the winter and early spring in northern states such as Colorado, we tend not to be exposed to as much natural sunlight as our bodies need in order to produce vitamin D. Recent studies have linked vitamin D deficiency to a wide range of medical problems such as diabetes, osteoporosis, hypertension, multiple sclerosis, at least 16 different types of cancer, chronic fatigue and other diseases, including influenza.
In light of these concerns, a personal acquaintance of mine, Dr. Walter Willet of the Harvard School of Public Health, has become a strong advocate of vitamin D supplementation. He recently told CBS News (see link below) that “there’s very strong evidence that not getting enough vitamin D is likely to lead to excess risk of colon cancer, probably some other cancers, probably multiple sclerosis, probably asthma. And the list is rapidly growing.”
I have been testing many of my patients for vitamin D deficiency and have found that the problem is fairly common, particularly among patients with hypertension, diabetes and obesity. I began conducting these tests after I met Dr. Willet at a 2006 session of the Harvard Nutritional Roundtable, where he spoke about the health effects of vitamin D deficiency.
I have found that more than half the patients that my staff and I test are vitamin D deficient, and this is consistent with published reports.
Vitamin D is unlike other vitamins in that our bodies manufacture it when they are touched by sunlight. Many of us spend little time in the sunlight, especially during the winter and early spring. Some researchers believe that this accounts for the higher incidence of influenza in winter, as vitamin D is important for immune system function. When warmer weather arrives, we apply sunscreen in order to prevent skin cancer. Unless we take supplemental vitamin D, few of us are likely to get as much as we need.
The government currently recommends 200 to 600 IUs of vitamin D a day. The amount that any individual needs for optimal health is higher. How much higher depends on such factors as age, skin color—dark skin doesn’t absorb sunlight as rapidly—and how much time the person spends in the sun each day.
If you suspect that you have vitamin D deficiency, you should ask your physician to perform a simple blood test and, once the results are in, help you determine how much vitamin D your body needs for optimal health. Please be aware that it is possible to take too much vitamin D and, of course, it is possible to get skin cancer if you spend too much time in the sun each day. Your physician can help you make the best choices for your health. Expect to hear more about this important topic.
