How to Use Your Immune System to Stay Healthy

From the WebMD Archives

Do you seem to catch cold after cold, while your friends sail through winter unscathed? Maybe you need to think about strengthening your immune system.

You may pay more attention to the health of your immune system during the winter, when colds and flu surround you. But the truth is, your immune system has to work hard all through the year, whether it’s offering protection from a flu virus or an infection that could happen any time.

“We are endowed with a great immune system that has been designed evolutionarily to keep us healthy,” says Bruce Polsky, MD, interim chairman department of medicine and chief division of infectious disease at St. Luke’s-Roosevelt Hospital Center in New York City.

How the Immune System Works

The immune system is your body’s natural defense system. It’s an intricate network of cells, tissues, and organs that band together to defend your body against invaders. Those invaders can include bacteria, viruses, parasites, even a fungus, all with the potential to make us sick. They are everywhere – in our homes, offices, and backyards. A healthy immune system protects us by first creating a barrier that stops those invaders, or antigens, from entering the body. And if one slips by the barrier, the immune system produces white blood cells, and other chemicals and proteins that attack and destroy these foreign substances. They try to find the antigen and get rid of it before it can reproduce. Failing that, the immune system revs up even more to destroy the invaders as they multiply.

The immune system can recognize millions of different antigens. And it can produce what it needs to eradicate nearly all of them. When it’s working properly, this elaborate defense system can keep health problems ranging from cancer to the common cold at bay.

When the Immune System Breaks Down

Sometimes the immune system makes a mistake and identifies a substance as being harmful when it’s not – think pollen or pet dander. When the immune system revs up to fight these “invaders,” you have an allergic reaction.

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Nor can your body fight off every invader. Despite its marvels, the immune system does break down from time to time, says Polsky. “There are diseases that we have no control over, but lifestyle aspects are very, very important,” he tells WebMD.

Not eating healthily, being sedentary, not getting enough sleep, and being under chronic stress can all contribute to a weak immune system. When your immune system is depleted, bacteria, viruses, or toxins can overwhelm the body. The result? You get sick.

Building Healthy Immunity

There’s no single pill or supplement you can take to boost your immune system. Instead, adopting these healthy living habits can help improve your immunity for a lifetime.

Go for a walk: Sitting around not only can leave you feeling sluggish, it also can make your immune system sluggish. Exercise, on the other hand, helps boost immunity.

“We know exercise is good for immune function,” says Polsky. The good news, he says, is that you don’t need elaborate exercise programs and personal trainers. “Even fast walking – getting your heart rate up for 20 minutes three times a week -- is associated with increased immune function,” Polsky tells WebMD.

Researchers aren’t sure exactly how exercise helps strengthen the immune system. Studies show that people who exercise have better-functioning white blood cells (the ones that help fight off infection) than people who don’t exercise.

Also, exercise is associated with the release of endorphins. “These are natural hormones that affect the brain in positive ways,” Polsky says. They ease pain and promote a sense of relaxation and well-being – all of which can help you de-stress and sleep better, which in turn improve immunity.

Eat a healthy diet: Proper nutrition is essential for your immune system to work well. A diet high in empty calories not only leads to weight gain, but it can leave you more prone to infections. Plus, being overweight is associated with a number of health problems that can also drag your immune system down.

“When the immune system is down, you want to avoid things like alcohol and sugar, especially because microbes love sugar,” says Stephen Sinatra, MD, a certified nutrition specialist and assistant clinical professor of medicine at the University of Connecticut School of Medicine.

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A diet rich in antioxidant vitamins, on the other hand, can boost resistance to infection. Think about eating in color: dark green, red, yellow, and orange fruits and veggies are packed with antioxidants. Try berries, citrus fruits, kiwi, apples, red grapes, kale, onions, spinach, sweet potatoes, and carrots.

Other immune-boosting foods include fresh garlic, which may have antiviral and antibiotic properties, and old-fashioned chicken soup. Studies show that, if you do come down with a cold or the flu, a bowl of steaming chicken soup can ease inflammation and help you get well faster.

And mushrooms such as reichi, maitake, and shiitake may have a strong influence on immune function as well as enhance the production of chemicals that help your body respond to infection.

Get enough sleep: Regular bouts with insomnia may not only leave you feeling fatigued during the day, but also leave you vulnerable to illnesses, including colds, flu, and other infections. Long term, poor sleep also has been shown to increase the risk of other health problems, including obesity and diabetes.

The body uses sleep as a means of healing itself, says Scott Berliner, president and supervising pharmacist at Life Science Pharmacy in New York. When we don’t get enough sleep – or reach the deeper stages of sleep – healing is impaired.

It’s hard to measure exactly sleep’s protective effect on the immune system, and researchers don’t know precisely how sleep improves immunity. Like antioxidants, sleep may help reduce oxidative stress, which then stops cells from being weakened and harmed. But “clearly, sleep – at least seven hours a night – is associated with increased resistance to infectious diseases,” says Polsky.

Practice stress management: When your body is under constant stress, you’re more vulnerable to everything from the common cold to major diseases.

“Stress from time to time is not necessarily a bad thing. But to not have relief from the stress -- to be under constant stress -- is deleterious to health,” says Polsky. That’s because a steady cascade of stress hormones, such as cortisol and adrenaline, weaken the immune system.

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Chronic stress is linked to heart disease and hypertension, and it can also have an effect on white blood cell function, Polsky says.

“When I speak to people about lifestyle changes, I look at what they can do to manage their stress, whether it be meditating – maybe exercise is their form of meditation – whether it be spirituality of a religious nature. It really doesn’t matter,” says Berliner.

Don’t abuse alcohol or use recreational drugs: Drinking a moderate amount of alcohol appears to have some health benefits, such as lowering your risk of heart disease. What’s “moderate?” No more than two drinks a day for a man, or one drink for a woman. But drinking too much alcohol can inhibit the function of white blood cells and lower your resistance to infection, says Polsky. Using recreational drugs, including marijuana, has the same effect on white blood cells, weakening your immune system.

Strengthen relationships: Research shows that people with close friendships and strong support systems tend to be healthier than those who lack such supports.

A good sexual relationship may provide even more immune system benefits. A study of college students found those who had sex once or twice a week had higher levels of an immune system protein called immunoglobulin A (IgA) than those who had less sex. Sex may also help immunity by reducing stress and improving sleep.

“I tell people to get good love in their lives -- good support, good friendships, however they need to get that love,” says Berliner. Good relationships, along with a healthy diet, regular exercise, and adequate sleep, are part of a holistic approach to boosting the immune system and protecting yourself from disease. “And to treat any problem holistically, there is no one-pill approach,” Berliner says.

WebMD Feature Reviewed by Brunilda Nazario, MD on November 16, 2009

Sources

SOURCES:

Bruce Polsky, MD, interim chairman, department of medicine, chief, division of infectious disease, St. Luke’s-Roosevelt Hospital Center, New York City.

WebMD Feature: “Using Your Immune System to Stay Well.”

Stephen Sinatra, MD, assistant clinical professor of medicine, University of Connecticut School of Medicine; founder, New England Heart and Longevity Center Medicine, Manchester, Conn.

WebMD Feature: “How Antioxidants Work.”

Ann G. Kulze, MD, CEO & founder, Dr. Ann & Just Wellness, Mt. Pleasant, S.C.

Scott Berliner, supervising pharmacist, Life Science Pharmacy, Harriman, N.Y.

WebMD Medical Reference: “Use Your Immune System to Prevent Flu.”

WebMD Feature: “10 Surprising Health Benefits of Sex.”

Medline Plus: “Immune Response.”

Rosner, F. Chest, 1980; vol 78(4): pp 672-674.

© 2008 WebMD, LLC. All rights reserved.

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