Vitamin D Reduces Flu, Respiratory Viruses

GREENWICH, Conn.Vitamin D may reduce the incidence and severity of viral respiratory tract infections, including influenza, according to a new study published in journal PloS ONE.

As reported by Newswise, researchers followed 198 healthy adults during the fall and winter 2009 to 2010 to determine if the declining concentrations of vitamin D seen in the fall and winter in a temperate climate could be a factor in the seasonal increased prevalence of respiratory viral infections such as the flu.

In the double blind study, participants had blood samples drawn monthly using a 25-hydroxyvitamin D test to measure vitamin D levels. Participants reported any evidence of an acute respiratory tract infection (nasal congestion, sore throat, and/or cough with or without fever, chills, fatigue and general malaise).

Of the 18 participants who maintained vitamin D levels of 38 ng/ml or higher during the study period, only three developed viral infections. Of the 180 other participants, 81 developed viral infections. Those with the higher vitamin D levels also experienced a marked reduction in the number of days ill.

The findings suggest supplementing with vitamin D to achieve a blood level 38 ng/ml or higher could result in a significant health benefit by reducing the incidence of viral infections of the respiratory tract.