To investigate, researchers from the University of Tampere in Finland randomly assigned 164 male military recruits to take either 400 international units (IU) of vitamin D or inactive placebo pills every day for six months, from October to March, covering the months when people's vitamin D stores typically decline and when respiratory infections typically peak.
At the end of the study, which was published in the Journal of Infectious Diseases, the researchers found that men given a daily vitamin D supplement over a six-month period were less likely to take sick days from work than those who were given placebos.
In fact, 51 percent of the 164 male military recruits who participated stayed healthy for the duration of the study as opposed to just 36 percent in the control group, according to the scientists.
The body naturally synthesizes vitamin D when the skin is exposed to sunlight. Because rates of vitamin D insufficiency rise during the winter in many parts of the world, researchers have been interested in whether the vitamin might play a role in people's susceptibility to colds, flu and other respiratory infections.
Some past research has found that people with relatively lower vitamin D levels in their blood tend to have higher rates of respiratory infections than those with higher levels of the vitamin.
Recent studies have found that a whopping 2 out of 3 Canadians have less vitamin D than the latest research suggests is necessary.
Based on the growing body of evidence about the link between vitamin D and reducing risk for colorectal, breast and prostate cancers, the Canadian Cancer Society recommends that adults living in Canada should consider taking Vitamin D supplementation of 1,000 international units (IU) a day during the fall and winter, while adults at higher risk of having lower Vitamin D levels should consider taking Vitamin D supplementation of 1,000 IU/day all year round. This includes people who are older, dark sinned, don't go outside often and wear clothing that covers most of their skin.
All research on this web site is the property of Leslie Beck Nutrition Consulting Inc. and is protected by copyright. Keep in mind that research on these matters continues daily and is subject to change. The information presented is not intended as a substitute for medical treatment. It is intended to provide ongoing support of your healthy lifestyle practices.