Photo by Eric McNatt

Cold Busters Terri Yablonsky Stat, March & April 2008 Many products promise to supercharge your immunity. Which ones actually work?

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Your immune system protects you from marauding bugs and viruses. So it's natural to want to protect and even strengthen your immunity.

That's why immune-boosting diet supplements are such big business: in 2006, Americans spent more than $1.5 billion on them, according to the Nutrition Business Journal. But not all immune boosters work equally well—and some of them don't work at all.

We questioned experts in complementary medicine, including our own Andrew Weil, M.D., to find out which immune boosters are worth a try. We also asked which herbs and foods these experts recommend to improve immunity. Their answers follow. But first, two cautions:

• "People believe that because these products are natural, they're safe," says Melinda Ring, M.D., medical director of the Center for Integrative Medicine at Northwestern Memorial Hospital in Chicago. It's vital to mind warning labels and keep your doctor in the loop, since some herbs can interact with drugs or other herbs.

Superfoods

"Your body will absorb vitamins better through foods than through supplements," says Toni Bark, M.D., medical director of the Center for Disease Prevention and Reversal in Evanston, Illinois. "Diet is the basis of our building blocks." These superfoods are power-packed with nutrients that will help your body ward off infection.

Asian mushrooms (shiitake, maitake)
Active ingredients: Beta-glucans, a type of carbohydrate

Chocolate (dark)
Active ingredients: Antioxidants, magnesium, and potassium

Garlic
Active ingredient: Allicin, a sulfur compound that boosts the production of white blood cells

Red meat
Active ingredients: Selenium, zinc

Sweet potatoes
Active ingredients: Vitamin C, beta carotene

Salmon
Active ingredients: Vitamin A, vitamin D, selenium, omega-3 fatty acids

Berries (red and blue)
Active ingredients: Vitamin C, antioxidant compounds called flavonoids

Soybeans
Active ingredients: Vitamin B6, vitamin E

Tea (green and white)
Active ingredients: Vitamin C, antioxidant flavonoids

• Also, pills aren't shortcuts. The best way to strengthen your immune system is with a lifestyle that includes proper diet, exercise, stress reduction, good sleep, and a positive outlook, says Gary Deng, M.D., Ph.D., assistant director at the Botanical Research Center of the Memorial Sloan-Kettering Cancer Center Integrative Medicine Service in New York City.

Combo-Formula Immune Boosters

Over-the-counter products that combine natural immune boosters to help prevent or diminish colds and other ailments

COLD-fX

• Active ingredient: North American ginseng root
• Use: Take regularly to prevent illness or at the first sign of a cold
• Not for: People with serious medical conditions; people on blood thinners, except on doctor's orders

New Chapter Organics Host Defense

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• Active ingredients: A blend of 17 mushrooms
• Use: Take regularly to strengthen immunity
• Not for: People on blood thinners, except on doctor's orders

Nature's Way Sambucol Black Elderberry Original Syrup

• Active ingredient: Elderberry extract
• Use: To treat colds, flu, or sinusitis
• Not for: Long-term use

Nature Made TriMune

• Active ingredients: Andrographis, echinacea, vitamin C, zinc
• Use: To treat colds
• Not for: Long-term use

Individual Herbal Supplements

Herbs that have been shown to improve immune function

North American ginseng

• Use: Take regularly to prevent illness or at the first sign of a cold
• Not for: People with fibroids or certain cancers; can interact badly with drugs for heart disease, diabetes, or depression

Astragalus

• Use: Take regularly to prevent colds and flu
• Not for: People on immune-suppressing drugs to treat cancer, or organ-transplant recipients

Echinacea purpurea

• Use: Take at the first sign of a cold
• Not for: People with autoimmune conditions—such as lupus, rheumatoid arthritis, Graves' disease, or liver disease

Elderberry

• Use: To treat colds, flu, or sinusitis
• Not for: Long-term use

Terri Yablonsky Stat is a health writer in Northbrook, Illinois.

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