Vitamin D may be as effective as vaccination for seasonal flu.
In a recently published clinical trial, children who took a vitamin D supplement had a significantly lower risk of seasonal flu than children who took a placebo. Risk reduction with vitamin D was comparable to that seen in children who received the flu vaccine.
The influenza virus causes seasonal flu. Some years, the seasonal flu is relatively mild and other years it can be quite virulent. Although in any given year, most people do not get the flu, it is a serious disease.
With the advent of vaccines, hospitalizations and deaths have fallen but still an estimated 36,000 flu-related deaths and more than 200,000 hospitalizations occur annually.
Flu vaccines are not perfect. Since the strain of seasonal flu virus changes on a yearly basis, making a good vaccine is based on a "best guess". In those years when the vaccine matches the strain of influenza, vaccination can reduce influenza in the healthy population by as much as 70 percent to 80 percent.
However, if the match is poor, protection is also poor. In addition, some people can have reactions to the vaccine, especially people who are allergic to eggs.
We have been in a battle with viruses for millions of years - and have survived and thrived. What has nature given us to combat this constant viral attack? The answer seems to be vitamin D.
According to a recent study, published in the American Journal of Clinical Nutrition, vitamin D is as effective as vaccination for seasonal flu. This was an excellent study because it was randomized, double blinded and placebo controlled. For one year, 334 children were followed. Half received 1,200 IU of vitamin D daily and the other half received a placebo.
Only 10 percent of children in the vitamin D group came down with influenza compared to 19 percent in the placebo group. This level of protection was comparable to vaccination. There were no side effects.
Interestingly, vitamin D may have another advantage. In this study, children with asthma taking vitamin D had fewer exacerbations of their asthma and required less medication.
Vitamin D is not really a vitamin. It is a hormone that we all make in response to sunlight. Vitamin D induces the body to make compounds called antimicrobial peptides. These peptides not only strengthen the immune system, they are also toxic to the influenza virus. Seasonal flu happens in the winter when vitamin D levels are lowest. During the summer, when vitamin D levels are higher, seasonal flu is rare.
When I was younger, children spent more time outdoors. There were no computers, video games or cell phones and even air conditioning was rare. We got a lot of sun. Today, children spend more time indoors and when they are outdoors, sunscreen use is common. In my clinical experience vitamin D deficiency, in northern Illinois, is quite common. Vitamin D as a daily supplement seems to be prudent.
Nature gave us tools to survive and thrive. Vitamin D may be one of our best tools.
•Patrick B. Massey, M.D., Ph.D is medical director for complementary and alternative medicine for the Alexian Brothers Hospital Network.