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The sunshine vitamin may help boost your immune system’s
response to all flu viruses—including H1N1. Here’s how to
ensure you’re getting enough vitamin D
Taking vitamin D supplements may help protect you from the
H1N1 virus, a U.S.-based researcher says.
“Vitamin D fights common seasonal influenza and H1N1 in
several ways,” says William Grant, founder of the
Sunlight, Nutrition And Health Research Center in
California. Primarily, research in the past few years has
found that vitamin D helps you fight off the flu by
supporting your immune system’s response to viruses.
A 2007 study on post-menopausal African-American women (who
are naturally deficient in vitamin D) found that those who
took 2,000 IU per day of vitamin D had a 90% reduced risk of
contracting the seasonal flu over those who took a placebo.
Though there haven’t been any randomized tests conducted
on H1N1, Grant says research shows vitamin D will also work
in preventing the virus. “H1N1 is largely seasonal,” he
says, adding that “the five groups that are shown as
having more adverse effects from H1N1 are known to be
vitamin-D deficient: pregnant women, Aboriginal people,
obese people, people with type-2 diabetes and children with
neurological diseases.”
How do you know if you’re deficient in vitamin D? If you
live in Canada during the winter, you probably are.
“It’s impossible to make enough vitamin D in Canada from
sun right now,” says Grant, who receives research funding
from the Vitamin D Society in Canada and Bio-Tech-Pharmacal,
a U.S.-based pharmaceutical manufacturer that produces
vitamin D supplements. To boost your vitamin-D levels, he
recommends taking a supplement of 1,000 IUs or more every
day. “If you haven’t been taking vitamin D for a long
time, take large doses—10,000 IU per day for several
days—then go down to 2,000 to 4,000 IU per day throughout
the flu season.” (Most vitamin D supplements on the market
have 1,000 IU per tablet, which is what the Canadian Cancer
Society recommends as a daily dose.)
While Health Canada is currently reviewing the health
benefits of vitamin-D supplementation, they still recommend
that people ages one to 50 get their daily dose of 200 IU of
the vitamin from drinking two 500 mL glasses of milk. People
over 50 are advised to take a daily supplement of 400 IU and
it is not recommended that people take more than 2,000 IU
per day. Grant says that’s not enough to make a difference
to your immune system.“400 IU doesn’t do anything,” he
says. “If you are out in the sun all day in the summer you
can make at least 10,000 IU of vitamin D per day.”
Still confused? Talk to your doctor about their
recommendations for your situation, and consider getting
your vitamin D levels tested.