Think immunity is just at the mercy of your genes? To some extent it is. But stress level, the amount and quality of sleep, and diet actually play a much larger role than you think. Keep these tips in mind to boost your immunity and keep colds and other illnesses at bay.

Vitamin D

Activated in your skin by the sun, this pro-hormone used to be known primary alongside calcium for providing bone health and preventing rickets. Now most scientists and health professionals know that Vitamin D, or cholecalciferol, influences our immune systems as well. You can get Vitamin D most directly from the sun itself. But you can eat it up too by adding cod liver oil, fortified milk, cereals, eggs, and fish into your diet.

Other Vitamins and Minerals

Found in meat, fish, oysters, nuts, whole grains, yeast, and beans, zinc is one of the biggest stars in the world of immunity. But it's important to avoid taking either too little or too much it: the current Recommended Daily Allowance is 11mg/day for men and 8mg/day for women. Many other minerals and vitamins, such as the B vitamins, selenium, iron and Vitamin C, are also helpful to immunity, reminding us of how important a varied, balanced diet is to overall health. Take note: most of the B vitamins and Vitamin C are susceptible to being destroyed by cooking, so make sure some of your everyday chow is raw.

Intestinal Health

If your body is too busy dealing with inflammation (like IBS and migraines), food allergies, and delayed food sensitivities, it will have a hard time keeping up with immunity as well. Since much of a person's immune strength lies in their intestinal tract, it's important to keep your intestines healthy. A few ways to do this are to eat a whole, unprocessed diet with limited or no food additives or ingredients you might be allergic to. One way to help keep your intestines healthy is to add pro-biotics (beneficial bacteria) such as yogurt or kefir, but make sure they don't have too many additives and sugar.

Additives and Refined Sugar

Additives, such as sulfites, can hamper the effectiveness of vitamins in the food you're eating--the very same vitamins that help keep your immune system working properly. Extra sugar, especially refined sugar, needs your precious nutrients to digest it. Thus, refined sugar can rob your body of nutrients by utilizing the body's vitamins and minerals for sugar digestion--vitamins and minerals that would have normally been used for your immunity.

Though I wouldn't recommend it, you can try this experiment: allow yourself to get really stressed out, and while doing so consume lots of your favorite sugary desserts. Chances are you'll be calling in sick in a few days! There's nothing like both an intense amount of stress and sweets to bring down your immune system.



Spices and Herbs

Some of the best immune-building tools lay right smack in Mother Nature's own sugar-free spice rack. Fresh raw garlic has long been known to have antibacterial abilities, and some argue it's an anti-viral too. For it to be more effective, try to take it raw when possible. In addition, oregano (frequently found on pizzas and in pasta sauces) and turmeric (the spice used in mustard and in some Indian recipes) have been known to help keep your immunity revved up.

Other Foods

There have been a lot of recent rumors about mushrooms being a "Power Player" in the world of immunity. While we're waiting, it certainly wouldn't hurt many of us to include more of them in our diet. Other Power Foods that have more studies behind them for disease-fighting potential are tea, soy, and cruciferous vegetables, such as broccoli, which contains cancer-fighting sulforaphane.