Photo of a woman with a respiratory infection
If you are prone to respiratory tract infections, you may be low on vitamin D

Vitamin D reduces respiratory infection rate

15 January, 2013

Natural Health News — Supplementing with vitamin D significantly reduced respiratory tract infections among men and women at risk of contracting them, according to a new study.

Researchers from Sweden’s Karolinska Institut studied 124 men and women with an antibody deficiency or history of more than four bacterial respiratory tract infections per year. The participants were given either 4,000 international units (IU) vitamin D per day or a placebo.

The subjects, whose blood levels of vitamin D were lower than normal,  were asked to keep a daily record of symptoms arising from the respiratory tract, ears and sinuses; antibiotic treatment, and other factors. After a year of treatment, the researchers analysed several outcomes most important of which was frequency of illness. Blood levels of vitamin D and antibiotics use were also assessed.

Those who received vitamin D showed significantly raised levels of vitamin D in their blood samples. They also had 23% fewer respiratory tract infections and there was a 63.5% reduction in antibiotic use over those who took the placebo.

Benefits for those low on vitamin D

The findings, reported in the journal BMJ Open, are seemingly in contrast with another recent trial in the Journal of the American Medical Association (JAMA) in which vitamin D failed to show a protective effect against viral respiratory tract infection incidence or severity in a New Zealand population.

However, the JAMA study involved healthy individuals whose vitamin D levels were normal. In addition, in this study the  supplement was administered in large doses on fewer occasions, and this is believed to be less effective than the daily administration used in the current study.

Lead author of the BMJ study Peter Bergman noted that “Our research can have important implications for patients with recurrent infections or a compromised immune defence, such as a lack of antibodies, and can also help to prevent the emerging resistance to antibiotics that come from overuse.”