Feed a Cold?
From chicken soup to supplements, there are hundreds of myths about "cold cures." Here's the science.

Before she became a full-time mom, my mother was a registered nurse. It was a career she had been proud of and whenever my sister or I got sick, she jumped right back into that role, doing everything short of donning her starched white nursing cap. She'd examine the thermometer critically and shake it down with a crack of her wrist, and announce, "You'll be spending the day in bed!" No child could have been better cared for. A glass of ginger ale (with a bendy straw) was always placed in easy reach. And I can still taste her chicken soup, with its perfectly cooked noodles.

Mom was following a timeless tradition: people have always looked to food as medicine. This cold and flu season, I decided to look into the beliefs long held by my mom and many others to see which are nutritionally valid and which are merely folklore.

Sip chicken soup

It turns out there is something to chicken soup after all. In one study, researchers measured nasal mucus velocity (science-speak for "runny nose") and nasal airflow resistance (stuffy nose) after volunteers drank cold water, hot water or chicken soup. Of the three, hot chicken soup was the most effective at making noses run—a good thing since nasal secretions help rid the body of pathogenic viruses and bacteria. Like any hot liquid, soup also helps hydration and raises the temperature of the airways, both important for loosening secretions. Adding a few hot chiles, as chef Rick Bayless does (see "Home Remedies," below), might help loosen things up even more.

Try vitamin C

Ever since biochemist Linus Pauling proposed megadoses of vitamin C to stave off cold symptoms, research has been piling up to assess its effectiveness. For perspective, I turned to a well-regarded review of 29 studies that involved more than 11,000 participants. The reviewers found that vitamin C failed to reduce the incidence of colds. But overall, with doses of 200 mg or greater (more than twice the 60-75 mg current recommended dietary intake for adults), the duration of colds was shortened by about 8 percent—not a huge difference, but something. There was also a significant reduction in the number of days subjects took off from work or school, which suggests vitamin C might help reduce a cold's severity. 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 milligrams per day. More than this can cause an upset stomach.

think before you zinc Zinc's effectiveness against cold symptoms is more controversial. One study found that zinc lozenges shortened the duration of colds by one-half, while others found no advantage over a placebo. If you want to try zinc lozenges, follow the protocol used in scientific studies: take the lozenges every two hours and stop when your symptoms die down. Don't assume more is better; excessive doses of zinc can interfere with the absorption of other minerals, and high doses can be toxic.

Get a dose of vitamin D

Since colds and flu tend to strike during the darker winter months, some researchers believe a lack of vitamin D, the "sunshine" vitamin, might have something to do with making us more susceptible. At least one study found that a group of kids who took vitamin D supplements had fewer colds than another group that didn't. There's still much to learn, but unless you get steady exposure to the sun in the winter it seems prudent to take a multivitamin that contains 100 percent of the daily value for vitamin D.

Don't avoid dairy

Some people avoid dairy products because they are thought to increase mucus secretions, but scientific evidence has yet to support this. There may be some placebo effect at work: interestingly, people who say they believe that milk causes more mucus production tend to report more respiratory symptoms after they're given milk. But 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. Don't skimp on calcium-rich milk and especially not yogurt, which contains beneficial bacteria that may actually stimulate the immune system.

Today, I wonder if my mother would have given me something else to wash down with my ginger ale (maybe vitamin C?). I do know that she made me feel loved and cared for, and that did wonders for my prognosis.

And without a doubt the chicken soup helped.

Rachel Johnson, EatingWell's senior nutrition advisor, is dean of the University of Vermont College of Agriculture & Life Sciences.

Home Remedies

We asked some of the leading experts in the world of food and health what they feed a cold:

Grace Young

Food writer; Author, The Wisdom of the Chinese Kitchen

"Throughout the year I make a point of eating jook (rice porridge). Rice is a harmonizing food, neither yin nor yang; the Chinese believe that porridge cleanses the body and also hydrates it. When I was a child and got sick, my parents always gave me jook…like many Chinese, they felt chicken broth is too rich for a sick body."

Marion Nestle Ph.D., M.P.H.

Professor of Nutrition, Food Studies and Public Health, New York University; Author, What to Eat; EatingWell Advisor

"Lots of fluids—teas, herbal and otherwise…aspirin, decongestants and a box of tissues."

Walter Willett, M.D.

Professor of Epidemiology and Nutrition, Harvard School of Public Health; Author, Eat, Drink, & Weigh Less

"I do get my flu shot, but I don't really do anything special; the main point is to be in good shape nutritionally and physically year-round so that our defenses are strong all the time. One key factor in immune defense is adequate vitamin D…I believe that almost everyone should take 1,000 IU [international units, daily] unless they get an unusual amount of sun exposure."

Rick Bayless

Chef, Frontera Grill and Topolobampo, Chicago; Host, "Mexico: One Plate at a Time" (PBS)

"I always go for something spicy. My greatest comfort food is chilaquiles with a spicy chipotle-tomatillo sauce—especially good when you don't feel well. But a big bowl of chicken soup with chopped serrano or jalapeno chiles and a handful of cilantro isn't too shabby either. Chiles speed up your metabolism (and just make you feel a whole heck of a lot better)—and anything with a lot of green chiles is packed with vitamin C."

Dean Ornish, M.D.

Founder, Preventive Medicine Research Institute, Sausalito, CA; Author, Dr. Dean Ornish's Program for Reversing Heart Disease

"Since I changed my diet at age 19, it's rare that I get sick. I also take 3 grams per day of fish oil and a multivitamin. Yoga and meditation help, along with regular moderate exercise. Most of all, being happy makes a difference—when you're depressed, so is your immune system. When I'm with my wife, Anne, and my son, Lucas, I'm the happiest guy in the world."

By Rachel Johnson, Ph.D., M.P.H., R.D., EatingWell.com