Are you one of those folks with a life-threatening egg allergy? If so, many experts are recommending you avoid the H1N1 or swine flu vaccine.

However, that leaves folks feeling very vulnerable – especially as flu season begins and reports of swine flu surface. How do we keep ourselves healthy in the face of a worse-than-usual flu season?

This problem may have prompted a lot of interest in vitamin D. Given the role of vitamin D in our bodies’ immune response, it’s no surprise. Some medical experts are now hypothesizing that vitamin D also plays a key role in flu season: as our stores of vitamin D drop (from our summertime sun exposure), the chances of our developing an illness increases. The hypothesis is that the germs are always there, year round: however, we only get sick when our vitamin D levels drop.

This could be the reason we get sick more often in the winter and less often in the summer. You see, the vitamin D we have stored in our bodies has a half-life of 20 to 29 days. This means that 50 per cent is gone in 3-4 weeks without significant sun exposure.

Coincidentally, flu season typically begins in November – about 8 weeks after the kids are back in school (and no longer spending the whole day outside getting sun). At this time of year in the northern hemisphere, the days are appreciably shorter than the nights; we’ll be bundled up against the cold; and, the majority of the population will have less than 25 per cent of their summertime vitamin D stores remaining.

Widespread vitamin D deficiency is now believed to be the norm rather than the exception. Given our society’s use of sunscreen, UVB exposure is no longer a primary way to get vitamin D. This leaves most of us chronically depleted of the sunshine vitamin.

All this has researchers focusing more and more on the role that vitamin D plays in health of all kinds. Recent research regarding pregnant women and vitamin D showed that it reduced the risk of premature labor as well as small birth weight babies – but the same research also showed that pregnant women who took 4000 IU of vitamin D a day reduced their risk of infections of all kinds, particularly respiratory infections such as colds and flu as well as infections of the vagina and the gums. Seems to be yet another indicator that perhaps vitamin D is a good preventative that helps the body fight off viral and bacterial infections naturally.

So, what do you do if you find yourself either unable (due to allergy) or unwilling to get the H1N1 shot? Boosting your immunity with vitamin D seems a common sense approach.

Dr Bruce Hollis, author of a recent study on vitamin D and pregnant women, says that every pregnant woman should be on at least 4,000 IU of vitamin D, while nursing mothers need 6,400 IU (so that their infants get enough vitamin D). For the rest of us, many doctors recommend supplementation of 2,000 IU for adults, while children should get about 1,000 IU. High dosages of vitamin D beyond these levels are not recommended without medical advice and monitoring, as high levels of vitamin D are associated with toxicity.

Sources: Wikipedia, Food Consumer, CBC News, Health Net