It's no secret that cold and flu season peaks in winter. And if you're looking for ways to stay well, one priority, say experts, is simple: Follow a wholesome diet, just as you should any time of year. But that can be a tall order during the busy holiday season, when hectic social schedules and family commitments often interfere with regular meals.

Nutritionists recommend foods -- not supplements -- to help you stay strong through the winter.

Food alone can't protect against the common cold or influenza, and the science isn't yet clear on which or how much of some nutrients may help bolster immunity to reduce your risk of getting sick. But experts agree that a diet rich in a variety of produce, whole grains, lean proteins, and low-fat dairy products -- along with adequate sleep, moderate exercise, and minimal stress -- contributes to a well-functioning immune system and may promote a faster recovery if you do come down with a cold or flu. CookingLight.com: Choose healthful treats this holiday season

Stay hydrated

Water is the largest single constituent of the human body -- contributing to at least half your body weight -- but it's "also a forgotten nutrient," says Jennifer K. Nelson, M.S., R.D., director of clinical dietetics at the Mayo Clinic in Rochester, Minnesota. This essential nutrient (meaning it's one the body can't produce on its own) promotes healthy muscle, bone, and blood.

Adequate hydration is even more important once you're sick because fluids lost through sneezing, watery eyes, and a runny nose need replacing. "When you have a mild fever, your body becomes more dehydrated as a result. So drinking plenty of fluids is probably the first line of defense," Nelson says. CookingLight.com: Water isn't the only way to stay hydrated

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The Institute of Medicine (IOM) recommends an average 11 cups of fluids daily (from beverages and foods) for healthy women, while men need about 15.5 cups per day. Water, coffee, tea, and juice, as well as water-filled foods such as fruit, vegetables, soups and stews all count toward daily hydration needs.

Choose food

While it's known that certain nutrients like vitamins C, E, and A, as well as the mineral zinc, are associated with immune functions, it's hard to attribute specific immunity-boosting benefits to any one nutrient because of inconclusive research. "Many studies have been done in nutrition and immune function, involving numerous nutrients -- and [they] come out with different, often contradicting results," says Dayong Wu, Ph.D., a scientist in the Nutritional Immunology Laboratory, the USDA Human Nutrition Research Center on Aging, and assistant professor at the Friedman School of Nutrition and Science Policy at Tufts University.

Because a nutritional intervention may have different effects on people of different ages or nutrition status as noted in scientific studies, Wu says, it's difficult to make broad recommendations based on study findings. "In general, it's easier to see positive, immune-strengthening results by supplementing someone with a vitamin or mineral that he is deficient in," he says. The same benefits may not confer to "people with adequate intake."

That's why Julia Zumpano, R.D., of the Cleveland Clinic Department of Preventive Cardiology, recommends foods -- not supplements -- to help you stay strong through the winter. "An overall healthful diet rich in vitamins and minerals is your best bet for the cold weather months," says Zumpano. "You'll also benefit from other nutrients not typically found in supplements when you eat a whole food." She encourages plenty of fruits and vegetables (for vitamins C and E); whole grains, lean meats, and poultry (for zinc); and low-fat dairy products (for vitamin A). For example, in addition to vitamin E, a whole grain like quinoa or rye bread offers fiber, B vitamins, minerals, and other nutrients, which support overall good health. CookingLight.com: Pomegranates pack a punch

Fruits, vegetables, and seafood may also help you enjoy a healthier winter. Pumpkin, butternut squash, and other deep-hued orange produce provide beta-carotene, which is converted in the body to vitamin A. Choose citrus, like grapefruit, oranges, kumquats, tangerines, and clementines as well as canned tomatoes, chiles, or pineapple for vitamin C. Oysters offer zinc.

Check out our gallery for recipes that deliver these healthful nutrients, plus information on how green tea and yogurt may help your immune system this winter.

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