By Brierley Wright, M.S., R.D., Nutrition Editor, EatingWell Magazine
It's that time of year when any sniffle, cough or sneeze is noticed-and if it didn't come from you, chances are you're subtly putting a little space between you and whoever it came from.
There's no better time than the present to talk about immune-boosting myths-from colds to allergies. (Interested in other myths? Here are 13 of the biggest food and nutrition myths busted.)
Read on so that you're not duped by these four myths about boosting your immunity, as we reported in EatingWell Magazine.
Myth: Vitamin C will ward off a cold.
It won't. Vitamin C has long had a reputation for helping prevent colds and people often gulp megadoses when they feel cold symptoms coming on, but clinical studies have shown no effect for vitamin C in cold prevention in normal situations. However, research has shown that doses of 200 mg or greater (more than twice the 60-75 mg current recommended dietary intake for adults) may help reduce the duration of colds slightly. The likelihood of success seems to vary with the person-some people improve after taking vitamin C supplements, others don't. Try it and see for yourself, but don't exceed 2,000 mg per day. More than this can cause an upset stomach.
Similarly, zinc lozenges may also help cut the number of days you're sick. In a study in the Journal of Infectious Diseases, adults who took zinc in lozenge form (13.3 mg every 2 to 3 hours for as long as their cold lasted) within a day of noticing the telltale signs kicked the bug about 3 days sooner than those who got a placebo. Though that dose exceeds the recommended daily max of 40 mg, it's safe for a 3- to 5-day period, says study author Ananda Prasad, M.D., Ph.D. Scientists think zinc binds to cell receptors in the mouth and throat, blocking the cold virus from attaching and spreading. Zinc comes in many forms, but only lozenges have been shown to be effective. Skip nasal sprays and swabs: they may damage your sense of smell. And zinc from food (beef, dark poultry meat, shellfish) probably won't help, either, as you can't get enough that way.
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Myth: Honey will "cure" your allergies.
The theory is this: Honeybees gather pollen from the very plants that cause your itchy eyes, so consuming a small daily dose of the local honey-and subsequently these pollens-may stimulate your immune system and reduce allergies, explains Miguel P. Wolbert, an allergist and immunologist at the Allergy & Asthma Care Center in Evansville, Indiana. But the pollens that cause sneezing and congestion-such as ragweed-are windborne, while the pollens bees collect are too heavy to fly in the breeze. Windborne pollens can fall onto flowers, get picked up by bees and end up in honey, says Wolbert, "but it's likely to be a very, very small amount." Not enough to make a difference. And, so far, no clinical evidence shows that honey alleviates allergy symptoms.
But don't nix honey quite yet. It may help soothe your cough. Researchers at Penn State University tested honey against dextromethorphan-the active ingredient in most cough medicines-as a cough suppressant for children and found honey to be more effective. Sweetness may be honey's "active ingredient." The brain part that registers sweet tastes and the part that causes coughing are located near each other so sensing sweetness may affect coughing, says researcher Ian M. Paul, M.D. One (major) disclaimer: Don't give honey to a baby younger than 1 year old: honey may contain spores of a bacteria that causes botulism, which an infant's immature immune system can't handle.
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Myth: Dairy will make you more congested.
Some people avoid dairy products when they're sick because they are thought to further increase mucus secretions, but scientific evidence has yet to support this. In a blind test using a soy-based drink with similar sensory characteristics as milk, subjects reported the same changes in mucus production as they did with cow's milk.
So go ahead and have that glass of milk or a latte-the vitamin D in it may help boost your immune system. In a study of more than 300 Japanese children, those who took daily vitamin D supplements (1,200 IU) were 40 percent less likely to get a common flu virus than kids who took a placebo. Studies indicate that the nutrient may help immune cells identify and destroy bacteria and viruses that make us sick, says Adit Ginde, M.D., M.P.H., a public health researcher at the University of Colorado School of Medicine in Denver. Because a cup of milk delivers about 115 IU of vitamin D, and other food sources (oily fish, such as salmon or sardines) also only deliver small amounts, you may need to consider a supplement.
Don't skimp on yogurt, either-it contains good-for-you probiotics that may actually stimulate your immune system.
Myth: Vitamin-packed drinks will keep you from getting sick.
Drinks like Airborne and Vitaminwater "Defense" sound appealing, but really aren't worth it. Here's why: As with many label claims, Airborne's current one begins with a kernel of truth: vitamins A, C, E, zinc and selenium-nutrients in the supplement-are among the vitamins and minerals that our immune systems need to function efficiently. According to a 2002 report in the British Journal of Nutrition, deficiencies of any of these nutrients (or of vitamins B6 or B12, folic acid, copper or iron) can depress immunity. But the key word is deficiency; most of us-save for smokers, pregnant women, breastfeeding women and the elderly-meet our needs for these nutrients with the foods we eat. (If you fall into any of those higher-risk categories, talk with your doctor before taking a supplement.) And more isn't better. Excess amounts of many nutrients are potentially harmful, and it's all too easy to go overboard. Just one tablet of Airborne contains 1,667 percent of the daily recommended value (DRV) for vitamin C. Vitaminwater's "Defense" drink, the label of which encourages you to stay healthy so you can use your sick days to "not go in" doesn't deliver the mega-high doses of nutrients that Airborne does. (A 20-ounce bottle of the water contains 150 percent of the DRV of vitamin C and 25 percent for four B vitamins and zinc.) But it delivers 125 calories per bottle.
Instead of vitamin- and mineral-packed drinks, a daily multivitamin/mineral supplement might come in handy this time of year. Don't risk your health or waste your money on anything beyond that.
Must-Read: 4 Myths About Vitamins and Supplements You Should Know
What's your favorite way to outsmart a cold?
By Brierley Wright, M.S., R.D.
Brierley's interest in nutrition and food come together in her position as nutrition editor at EatingWell. Brierley holds a master's degree in Nutrition Communication from the Friedman School of Nutrition Science and Policy at Tufts University. A Registered Dietitian, she completed her undergraduate degree at the University of Vermont.
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