Natural ways to guard against colds, flu — and serious viral illness

Even people who pay close attention to their health often could be do­ing more to boost their immunity.

Your body’s immune system consists of specialized cells and chemicals that kill and/or inactivate viruses and other invaders. When viruses invade your body, they not only can trigger colds and the flu, but also Epstein-Barr infections (which have been implicated in hepatitis and certain cancers) and severe acute respiratory syndrome (SARS).

Latest development: Immunity researchers are confirming the profound importance of eating a healthful diet — and finding other helpful ways for you to protect yourself from viruses.


Some people forget that good nutrition is as important for strong viral immunity as it is for the health of your heart and arteries. Despite all the talk about eating healthfully, most people fall short in at least one key food group.

Best immunity-boosting diet…

  • Complex carbohydrates should account for about 50% to 60% of your total daily calories. Good choices: Whole grains, such as brown and basmati rice, and legumes.
  • Vegetables and fruits (preferably organic) — have one or two servings at each meal. Good choices: Papaya, pineapple or peaches with breakfast… garden salad with fresh tomatoes with lunch… and steamed carrots and broccoli with dinner.
  • Fats should account for 20% to 25% of your total daily calories. Choose unsaturated oils that are rich in omega-3 fatty acids. Good sources: Cold-water fish, such as salmon, mackerel and sardines… avocados … nuts (particularly walnuts and almonds) and seeds (particularly flax).
  • Protein should make up about 20% of your diet. Good choices: Protein from animal sources, such as fish, poultry, lean meat, low-fat milk and eggs. The vegetable protein found in grains and legumes (beans) also is nourishing. However, if you eat mostly plant-based proteins, take 12 g daily of whey protein (milk protein without fats or lactose) as a supplement.
  • If it’s difficult to maintain this daily diet, I recommend taking supplements to compensate for any missing nutrients. In addition to a daily multivitamin, take 200 mg to 500 mg of vitamin C… 400 international units (IU) of vitamin E… 200 micrograms (mcg) of selenium… and 15 mg of zinc.


    Other ways to maximize your body’s virus-fighting power…

  • Avoid fried foods. Even an occasional serving of french fries or fried chicken can compromise your body’s immunity. That’s because fats are oxidized during the frying process, creating compounds that damage all cells, including those that fight viruses.
  • My advice: For optimal benefit from a generally healthful diet, avoid all fried foods. Grill (with low heat), boil, steam or bake your food instead.

  • Limit alcohol consumption. Alcohol can depress immune function. Studies have linked excessive alcohol consumption to susceptibility to lung infections, including bacterial pneumonia and tuberculosis.
  • My advice: Drink alcohol in moderation (up to one drink daily for women… two for men) — or not at all.

  • Drink pure water. Most people don’t consume enough water. Water is one of the simplest ways to flush toxins effectively from the body and to introduce the minerals and trace minerals that have been shown to support immune function.
  • Even though some experts don’t believe that it’s necessary to drink as many as eight eight-ounce glasses of water daily, I stand by this advice. If you exercise — even if you don’t sweat — you need even more water, because greater amounts of it are lost from the lungs due to exhalation. During winter, excessively heated rooms also deplete water from your body.

    My advice: Don’t count soda, juice or other sugary beverages as part of your daily water quota. Drink pure spring water, such as Evian or Volvic, or filtered tap water. It helps flush viruses from your body without the immune-depressing effects of sugar and other additives.

  • Get enough sleep. A study published in Nature Reviews Immunology in 2004 showed that insufficient sleep inhibits the production of chemicals, such as cytokines, which help boost the body’s immunity. Not surprisingly, sleep deprivation is associated with increased rates of infection.
  • My advice: Most people need at least eight hours of sleep each night to restore normal body functions. If you feel rundown or are battling the early stages of a cold or other viral infection, try to get even more sleep.

    Important: Just being in bed for eight hours does not count if you’re having trouble falling asleep or are waking up during the night. If this occurs, ask your doctor for advice on improving the quality of your sleep.

  • Exercise — but not too much. Regular exercise has been shown to neutralize inflammatory chemicals and improve the function of the body’s natural killer cells — both key players in viral immunity.
  • But overly strenuous workouts, such as running a marathon, can have the opposite effect — triggering the production of cortisol, adrenaline and other stress hormones that suppress immune function and increase your odds of contracting an infection.

    My advice: Up to one hour a day of moderate exercise (such as brisk walking, bicycling or swimming) is right for most people. Let your body be your guide — if you feel exhausted and generally worse after you exercise, cut back.

  • Take a sauna. Dangerous chemicals from the environment, including the pesticides that we consume in nonorganic foods, cause an imbalance in the immune cells that fight viral infections. A sauna helps your body to release these chemicals via perspiration.
  • My advice: Take a dry sauna once or twice weekly. Don’t exceed 20 minutes, and drink at least an extra quart of pure water to compensate for what you lose through perspiration.

    Caution: Saunas may not be safe for people over age 65 or anyone who is weak or has a fever.


    The leaves, stems and roots of some plants are concentrated sources of powerful antiviral compounds. Unless you have a chronic viral infection, such as chronic hepatitis, it’s usually best not to take these on a regular basis.

    However, if you’re under considerable stress, feel rundown or are exposed to viral illnesses, consider taking one or more of the following supplements throughout cold and flu season… *

  • Astragalus. Prized in Chinese medicine for its ability to restore the body’s energy, this herb strength­ens anti­viral defenses by stimulating the production of interferon, a substance that inhibits viral growth. Typical dose: As a tea, drink one cup twice daily.
  • To prepare: Simmer 30 g of dried astragalus root in one cup of water for 20 minutes. Or take two to three 500-mg capsules twice daily.

  • Ginseng. This herb is known as an energy tonic, but it also stimulates the immune system. Typical dose: Take a 250-mg capsule twice daily (choose a standardized extract containing 30% of the active ingredient ginsenosides per 250 mg).
  • Caution: Don’t take ginseng if you have high blood pressure, a fever or an active infection. This herb also should be avoided by people who take a monoamine oxidase inhibitor (MAOI) antidepressant, such as phenelzine (Nardil) or tranylcypromine (Parnate).

  • Acemannan. This aloe vera extract has been shown to increase the activity of virus-killing T-cells and stimulate the release of interleukin-1, an important immune system messenger chemical. Acemannan is available at most health-food stores in a product called Manapol, manufactured by Carrington Labs. Typical dose: One 80-mg capsule one to three times daily.
  • *If you use prescription medication, are pregnant, nursing or have a chronic disease, such as diabetes or heart, liver or kidney disease, do not take any of these supplements without consulting your doctor.