This week I came across another study showing that Vitamin D is a flu fighter. The study has just been published online, ahead of print, in the American Journal of Clinical Nutrition.
In the study children were asked to swallow six pills a day (25% dropped out). Half of the children's pills were placebos (fake). The pill givers did not know which pills were fake (double blind).
Incidence of influenza A was 10.8 percent among the 167 kids who received vitamin D pills. That's in contrast to a flu rate of 18.6 percent among an equal number of children getting identical looking inert pills. Doctors monitoring the trial confirmed flu cases using a test to assay for the influenza-A germ.
The study also noted that two asthma attacks occurred during the trial among kids getting the vitamin, compared to 12 in the unsupplemented group. The study doesn’t say whether the same number of kids with a history of asthma were in each group so this result may not be valid.
The researchers also stated that it may take almost three months “to reach a steady state of vitamin D concentrations by supplementation". I interpret this to mean that takes our bodies about 90 days to accumulate an effective Vitamin D concentration (less illness after 3 months of taking vitamin D than during initial 3 months).