The vitamins and selenium in One A Day multivitamins “support” immunity, says Bayer, while the antioxidant vitamins in Centrum Silver “help support the immune system,” says Pfizer.
Has Bayer or Pfizer tested its multivitamins to see if all that support keeps customers from getting sick?
Nope. Perhaps that’s because the companies are familiar with the results of three good studies conducted since 2002 in Canada, the Netherlands, and Scotland on a total of roughly 2,150 middle-aged and older men and women.
Those who were given a standard daily multivitamin— one that supplied the Daily Value (DV) for most vitamins and minerals—for at least a year got sick just as often as those who were given a placebo. And in the two studies that looked, the multi takers were as likely to get just as sick, and to remain sick for just as long, as the placebo takers.
“It’s possible that any benefit of taking a multivitamin would be dwarfed by other factors that influence whether or not someone gets sick, such as age, general health, or use of medications,” says researcher Maria Sundaram, who studies vitamins and immunity at the Marshfield Clinic Research Foundation in Wisconsin.
Sources: J. Am. Geriatr. Soc. 55: 35, 2007; BMJ 331: 324, 2005; JAMA 288: 715, 2002.
Other relevant links:
- Take the recommended amount of vitamin D but don’t rely on it to prevent colds. See: Vitamin D Fails to Stop Colds
- Vitamin D may not help to prevent the flu. See: Can Vitamin D Prevent the Flu?
- Taking high doses of vitamin C does not lessen your risk for colds or respiratory infections. See: Does Taking Vitamin C Protect You From Colds?