NMSU branding

New Mexico State University

New Mexico State University

News Center

Healthy Diet, Habits Can Boost Immunity during Flu Season

LAS CRUCES - Eating well can be part of a long-term defense against the flu, along with healthy habits such as washing hands, exercising and managing stress, experts at New Mexico State University said.

A healthy diet can boost the immune system, experts at New Mexico State University say. Protein, vitamins A and C, and zinc, in particular, keep up the body's defenses. Dietitians say the best way to get these nutrients is to eat a variety of foods from all food groups. (10/20/2004) (NMSU Agricultural Communications Photo by J. Victor Espinoza)

"One way to help prevent flu is to have a healthy immune system, which begins with good nutrition," said Ann Bock, a human nutrition professor at NMSU. "Protein, vitamins A and C, and zinc are key nutrients in keeping up the body's defense mechanisms."

Adults need two to three servings of protein daily, Bock said. A 3-ounce serving of meat, poultry or fish-about the size of a deck of cards-provides high quality protein. An 8-ounce glass of milk or an ounce of cheese contains similar amounts.

A combination of two vegetable proteins, such as cereal grains eaten with peanuts, soybeans or pinto beans, supplies comparable protein if eaten at the same meal or at least in the same day, she said.

Bock recommends getting vitamins A and C from food rather than a vitamin pill. "Not only can you have side effects from taking too much of a supplement, but you also miss out on all of the other nutrients you get from eating the foods," she said.

A healthy adult needs a daily supply of about 60 milligrams of vitamin C, which is readily available in a glass of citrus juices or a fresh orange, lemon, lime or grapefruit.

"People have a tendency to self-medicate with supplements and mistakenly assume that if a little is good, a whole lot is better," Bock said. "Abusing vitamin C supplements can cause diarrhea. High doses of vitamin A from supplements can potentially increase the risk of birth defects in pregnant women or, in the elderly, produce metabolites an aging liver can't handle."

She recommends getting vitamin A from dairy products, fortified cereals and many vegetables. Some of the best sources are colorful: bright orange carrots, papaya and pumpkin, or deep green spinach, collards and mustard greens. A woman needs about 4,000 international units (IU); a man needs 5,000 IU.

Zinc is found in many animal products. The best source is shellfish, but fortified breakfast cereal is another source, Bock said.

For a healthy diet, it's important to eat a variety of foods from all food groups, Bock said. She recommends eating fruits and vegetables in their fresh, raw state as much as possible. Because fat can have negative effects on the immune system, limit fat intake and use lowfat cooking techniques, she said.

Exercise is another immune-booster, along with managing stress, said Bruce Jacobs, a health specialist with NMSU's Cooperative Extension Service. "We know that inactivity and stress adversely affect the immune system."

Experts recommend a half-hour of physical activity, such as a brisk walk, five times a week. Those who have medical conditions, are pregnant or are over 35 and inactive should check with a physician before starting an exercise program, he said.

Jacobs also recommends washing hands regularly because flu germs spread by direct contact. The Centers for Disease Control recommends washing with soap and water for at least 20 seconds, he said. Alcohol-based hand cleaners can also kill germs.

Cover your mouth and nose with a tissue when you cough or sneeze because germs cling to bare hands, Jacobs said. "If you can't get to that tissue quickly enough, cough or sneeze into your upper sleeve."

To keep from transferring germs, don't touch your eyes, nose or mouth.

As much as possible, avoid close contact with those who are sick. And if you're the one who's ill, stay home to prevent infecting co-workers, he said.

While even health-conscious people can catch the flu, immune-boosting habits may still help. "At the very least, it may reduce the severity of the illness," Jacobs said.