Stay Well This Winter with Natural Immune Boosters

Use these natural immune boosters to keep seasonal illness—and chronic disease—at bay.

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Getting enough sleep, eight hours a night for most adults, is vital for our immune function, as well as mental functioning and stress and weight management.

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For most of us, the standard week is hectic. From back-to-back meetings and household chores to social obligations and shuttling kids to activities (not to mention making time to exercise, eat well and spend time with our significant others and friends), many of us seem to have never-ending to-do lists. With these busy schedules, a bout of the common cold or flu can totally throw us off track. But ironically, the best way to preserve our health and maintain our on-the-go lifestyles is to give ourselves the time we need to slow down, treat our bodies right, and get the nutrition and rest we need. By eating a wide array of antioxidant-rich foods, boosting our resistance with powerhouse herbs, and getting adequate sleep and relaxation, we can remain healthy, even through cold and flu season.

Immune-Boosting Recipes

• Ziti with Chicken and Broccoli in a Creamy Sauce recipe
• Blueberry Banana Smoothie recipe

Natural Immune Boosters: Eat to Beat Illness

Eating well is one of the main ingredients in preventing illness. “The first step toward maintaining a healthy immune system is maintaining a healthy lifestyle,” says Marisa Moore, a registered dietitian and spokesperson for the Academy of Nutrition and Dietetics. Although eating a wide range of healthy foods including 4 1/2 cups of fruits and vegetables daily (as a general rule, produce with darker colors offers the most antioxidant value) will go a long way toward maintaining your health, certain foods and minerals pack a bigger punch than others.

“Vitamin A is crucial for the immune system,” says Joan Salge Blake, registered dietitian and spokesperson for the Academy of Nutrition and Dietetics. Vitamin A acts as a barrier against harmful bacteria, increases white blood cell counts and is a potent antioxidant, helping the body defend against the harmful free radicals that can damage cells and weaken the immune system, Blake says. But health experts recommend against superdosing with vitamin A supplements: Too much vitamin A can be toxic and lead to hypervitaminosis A, an overabundance of the vitamin that causes headaches, vomiting, drowsiness, dizziness, liver damage and decreased appetite. To safely boost your vitamin A intake, eat foods rich in beta-carotene such as carrots, sweet potatoes, pumpkins, cantaloupe, and other fruits and vegetables with a deep orange or red color. Beta-carotene can be stored in the body until it’s needed and poses no risk of hypervitaminosis. “When your body needs the nutrient, it will convert the beta-carotene into vitamin A,” Blake says.

Other vitamins and minerals required for a fully functioning immune system include zinc, vitamin C and selenium. A powerful antioxidant, zinc helps the body produce white blood cells and encourages healing. Good sources include whole grains, red kidney beans, green peas, and meat such as dark-meat chicken and lean beef. Vitamin C helps the body produce white blood cells and defend against harmful pathogens and microorganisms. In addition to citrus fruits, broccoli and red peppers are two excellent sources of vitamin C. Selenium also offers antioxidant activity; Brazil nuts and lean meats such as turkey and chicken are the best sources. “One ounce of Brazil nuts has 777 percent of the daily value of selenium,” Moore says.

Probiotics are beneficial bacteria vital to helping the body manage illness. Probiotics regulate potentially harmful bacteria in the colon and small and large intestine, which is where nutrients enter the bloodstream. Although people often use probiotic supplements, it’s preferable to find a food source of probiotics such as high-quality yogurt, kefir, kimchi or miso. “Acidity in the stomach can destroy probiotics, but food helps buffer the probiotics through the stomach and into the intestines,” Moore says.

Work It Out

Getting regular, moderate exercise is a crucial component in maintaining a healthy immune system. Public health guidelines urge us to get at least 30 minutes of moderate exercise daily. A wealth of studies support exercise’s role in illness reduction. For example, in a one-year study of 547 adults, those engaging in regular versus irregular moderate-to-vigorous physical activity demonstrated a 23 percent reduction in risk of upper respiratory tract infections. Exercise can also help moderate reductions in immune function as we age. Although immune function declines in the elderly, a study found that adults who engaged in higher amounts of physical activity experienced a reduction in upper respiratory tract infection symptoms during a one-year period.

Fitness enthusiasts may wonder whether to exercise or rest when a sickness is coming on. As a general guideline, if symptoms are from the neck up (such as the common cold), moderate exercise is acceptable or even beneficial, according to a report by the Department of Health & Exercise Science at Appalachian State University. If illnesses are systemic, meaning they affect the entire body (for example, the flu), bed rest is best, followed by a gradual progression back to normal training, as physical activity can worsen systemic illness. Although moderate exercise can help maintain a healthy immune system, prolonged heavy exertion lasting longer than 90 minutes can weaken immune function. Long, intense exercise can create an “open window” of impaired immunity, lasting from three to 72 hours, during which time it can be easier for illnesses to gain a foothold. Data from some studies have shown that athletes who ingest carbohydrates during periods of intense physical activity (such as running a marathon) will experience a lower disturbance to the immune system than those who avoid carbohydrates.

Natural Immune Boosters: Reduce Stress

One of the many reasons exercise may be so beneficial for the immune system lies in its ability to help reduce stress. In numerous studies, stress reduction has been found to enhance immune function. When we experience stress, our bodies increase our output of neuroendocrine hormones, particularly glucocorticoids and catecholamines, which have detrimental effects on immune function. Their actions, among others, are to reduce the production of antibodies and activity of NK (natural killer) cells. These effects can have severe consequences on health including not only enhanced susceptibility to colds and flus, but also delayed wound healing, impaired response to vaccination, and the development and progression of cancer, according to the Institute for Behavioral Medicine Research at the Ohio State University Medical Center.

The longer the duration of stress, the greater its negative effects on immunity. In a meta-analysis of nearly 300 studies on stress and health, researchers from the Universities of Kentucky and British Columbia found that stress of any significant duration, from a few days to a few months or years, led to a decline in all aspects of immunity.

In addition to stressful circumstances, researchers have found a link between repressed immune function and lack of social support. In a 2005 study of college students, health psychologists found that social isolation and feelings of loneliness each independently weakened first-year students’ immunity, as reported by the American Psychological Association. It appears that finding ways of managing stress—from breathing techniques to exercise to taking vacation time—and enhancing our social networks may both be vital to maintaining our health.

Get Adequate Sleep

Along with its crucial role in mental functioning and weight management, getting adequate sleep is vital to a properly functioning immune system. Studies show that people who don’t get enough sleep are more likely to become ill when exposed to a virus. When a sleep researcher at the University of Chicago exposed students allowed only four hours of sleep per night for six nights to the flu vaccine, their immune systems produced only half the normal number of antibodies in response to the viral challenge, the Mayo Clinic reports. Adults need seven to eight hours of sleep a night to function well; the National Sleep Foundation’s 2005 poll showed American adults averaged just 6.8 hours a night on weeknights—more than an hour less than most people need. The Mayo Clinic recommends nine to 10 hours of sleep for teenagers, and more than 10 hours a night for school-aged children.

Herbs for Immunity

Many herbal supplements can help keep immunity levels high throughout the winter months. Here are a few of our favorites. Which herbal remedies are most effective often depends on the person. Try all of these remedies to find the ones that work best for you.

Andrographis: Long revered in Traditional Chinese Medicine, andrographis (Andrographis paniculata) has historically been used to treat colds, fevers, bronchitis, diarrhea and liver disorders. Andrographis has been the subject of extensive research supporting its actions as a natural immune booster and liver protectant.

Astragalus: An adaptogenic herb that stimulates our natural killer cells, astragalus (Astragalus membranaceus) has been shown in studies to reduce the number of colds and to reduce cold symptoms once a patient does get sick.

Berberine: Berberine is a plant alkaloid with a history of use in Ayurveda (traditional Indian medicine), Traditional Chinese Medicine and by American Indian herbalists. Berberine is found in several herbs including Oregon grape root (Berberis aquifolium), barberry (Berberis vulgaris) and goldenseal (Hydrastis canadensis). Note: If you buy goldenseal, make sure the producer harvests sustainably, as the plant is endangered. A potent antimicrobial, berberine is effective against bacterial diarrhea, intestinal parasite infections and chronic bacterial conjunctivitis.

Echinacea: One of the top-selling herbal remedies, echinacea (Echinacea spp.) has a number of antioxidant and immune-stimulating constituents. It’s at its most effective when taken at the first sign of illness—and its effectiveness is dependent on heavy dosing. Majid Ali, an herbalist in Santa Monica, California, suggests taking one or two 300- to 400-milligram capsules every one to two hours during the first 24 to 48 hours of cold symptoms. Continue taking one or two apsules four times daily for three to five days after symptoms disappear.

Medicinal mushrooms: Shiitake, maitake, cordyceps and reishi are all potent immune boosters, as well as cancer fighters. You can often find a blend of these mushrooms available as an immune-stimulating supplement.

Rhodiola: If stress is an illness trigger for you, consider rhodiola (Rhodiola rosea), an herb that helps prevent adrenal exhaustion, helping the body cope with stress.

Natural Immune Boosters: Convincing Kids to Eat Right

Registered dietitians Marisa Moore and Joan Salge Blake agree getting kids involved in meal planning is the best way to encourage immune-boosting eating from an early age. Let kids choose ingredients at the store, or take them to the farmers’ market and encourage them to try something new every week.  Here are more tips for making eating well fun:

• Play the color game. Fruits and veggies in different colors offer different nutrients. When you go to the market, pick a color, and allow your child to select two fruits or vegetables of that color to create a dish or snack. Or tell kids to find one thing of each color: green, red, blue, white and orange.

• Get kids gardening. Children are more likely to try foods if they get to choose them. They’re even more likely to give them a chance if they had a hand in growing them themselves.

• Finger foods. Sometimes we just need to keep it simple. Let children dunk carrots in their favorite dressing or create pepper scoops by slicing a pepper into eighths, then serving them with a yummy salsa or hummus.

• Don’t give up. Children may try a food up to 10 times before it appeals to them, Moore says. “Sometimes kids don’t like the texture,” she says. If kids try a certain food and turn it down, consider preparing it a different way next time, but don’t give up on it.

DEBORAH R. HUSO is a freelance writer who grew up on a small farm near Shenandoah National Park. She writes on health and fitness, travel, outdoor recreation, environmental issues and wildlife conservation.