I agree with what is written on their web site. There is other studies that people with higher levels of
vitamin D are able to fight off the flu. More and more studies are finding that
vitamin D does boost the immune system for numerous illnesses including the flu.
Vitamin D supplements are very important during the fall and winter since we can't get it from sunlight. Interestingly a time when the flu is much worse.
Here is a good article about the health benefits of
vitamin D:
http://factoidz.com/the-health-ben... 
