Boost your immunityThey say you are what you eat, so it makes sense that eating healthy foods can help you stay, er, healthy.
"You can't underestimate the importance of good nutrition when it comes to...your immune system," says Karen Ansel, RD, a spokesperson for the Academy of Nutrition and Dietetics. "Vitamins, minerals, antioxidants—these are what keeps your body strong, and without them you're not giving your body the edge it needs to ward off infection."
And we're not talking just fruits and vegetables: Foods from every food group are represented here. Make them a part of your diet for your best defense against colds and flu.
A 2001 study in the journal Advances in Therapy found that people who took garlic supplements for 12 weeks between November and February got fewer colds than those who took a placebo. And of those who did get sick, those who took the garlic supplement felt better faster.
Garlic packs the biggest antioxidant punch when eaten raw. Flavor too strong for you? Consider taking aged-garlic extract capsules.
Eating lots of citrus—whether that entails digging in to orange and grapefruit slices, or using lemons and limes in recipes—will provide plenty of this powerhouse nutrient. Don't worry about overdoing it, since it's very hard to overdose on vitamin C. Anything your body doesn't use is just washed right out of your system.
Omega 3s may fight colds on more than one front. In a placebo-controlled 2011 study published in Brain, Behavior and Immunity, medical students who took fish oil supplements for three months had lower inflammation levels and also fewer symptoms of anxiety—a condition that can itself weaken immune function.
Anise seeds can be eaten (in rolls and cookies, for instance), but for cold-fighting the delivery method of choice is usually tea. According to the American Pharmaceutical Association's Practical Guide to Natural Medicines, a typical recipe is to add one cup of crushed anise seeds to one cup of hot water, and flavor with sugar, garlic, cinnamon, or honey (if desired). Sip this concoction up to three times a day.
Zinc supplements carry a risk of side effects such as nausea and headaches, however. A better bet, says Ansel, may be to get zinc straight from your diet. Oysters contain more of the nutrient per serving than any other food—but if you're concerned about staying healthy, you might not want to eat them raw. "Uncooked shellfish could contain harmful bacteria that could make you sick in other ways," Ansel says.
Fennel can be eaten raw or roasted, but you may get the best cold-fighting benefit from drinking a tea made from fennel seeds. Try Yogi Tea's Throat Comfort, or make your own with 1.5 teaspoons of fennel seeds and one cup boiling water. Steep for 15 minutes, strain, and sweeten with honey to taste.
Yogurt and kefir
The benefits of good bacteria may go beyond our gut. A 2011 review of the research found that consuming probiotics—whether in food or supplement form—lowers the risk of upper respiratory tract infections better than a placebo.
All tea—black, green, or white—contains a group of antioxidants known as catechins, which may have flu-fighting properties. In a 2011 Japanese study, people who took catechin capsules for five months had 75% lower odds of catching the flu than people taking a placebo.
Need another reason to turn on the kettle? Other research suggests catechins may help boost overall immunity, rev metabolism, and protect against cancer and heart disease.
Even that may not be enough, however, as studies suggest you need much more than that to harness the nutrient's cold-fighting benefits. "If you're sick, you should be eating a lot of vitamin C throughout the day—400 to 500 milligrams," Ansel says.
Getting your daily dose of vitamin D may keep colds at bay. A 2009 study from Massachusetts General Hospital found that lower vitamin D levels were associated with a greater risk of upper respiratory infections. In 2012, the same researchers found that Vitamin D supplements can help ward off kids' winter colds, as well.
Shiitakes, for example, contain lentinan, a nutrient that is thought to have anticancer properties. Other varieties, such as certain brands of Portobello, are grown in ultraviolet light to spur vitamin D production.
Skinless turkey breast
Chicken, turkey, and pork are all good sources of protein, but you can also get plenty from meatless sources such as beans, nuts, and dairy.
Bitter greens like arugula may even help relieve chest congestion, sniffles, and coughs. How? It's not entirely clear, although a 2011 British study found that mice that were fed green vegetables had more infection-fighting white blood cells in their intestines than those who were not.
Too often, however, the nutritional benefits of cocoa are overshadowed by the sugar and saturated fat found in chocolate bars and other treats. To reap the immunity-boosting benefits without the unhealthy extras, stick with bite-sized portions—about one quarter-ounce per day—of dark chocolate with a cocoa content of 70% or higher.
Carrots and sweet potatoes
Vitamin A is especially important for areas that go haywire when we catch a cold: It keeps the mucous membranes that line our nose and throat—one of the body's first lines of defense—healthy and functioning properly.
Vitamin E may be especially important for the health of our lungs, where it appears to fight the harmful process known as oxidative stress. A 2003 study in Scotland found that people with diets high in vitamins C and E had greater lung capacity and produced less phlegm.
Animal studies have shown that beta-glucan from oats can help prevent upper respiratory tract infection, and a few controlled trials have suggested that beta-glutan consumption can alter white blood cell activity in humans, as well.