10 easy ways to boost your immunity: From what you eat to where you sleep, simple lifestyle changes can help your body develop defenses that are not too weak, not too strong, but just right

Shape, March, 2002 by Mary Ellen Strote

If someone asked you what kind of immune system you wanted, you'd probably say one that's tough as nails, a real fighting machine. But be careful what you wish for. "You don't want to strengthen your immunity as much as you want to optimize it," says Lee Berk, Dr.P.H., M.P.H., an assistant professor of family medicine at the University of California, Irvine, College of Medicine.

In other words, your self-defense system needs to be strong enough to keep bacteria and viruses from entering your body and multiplying, and to reestablish health when disease does gain a foothold. But your immune response can be too powerful. When that happens, your immune system can mistake your own tissues for invaders, causing autoimmune illnesses like allergies or lupus. So rather than picturing your immune system as a mighty battalion of warriors fending off disease, picture it instead as a 911 dispatcher whose job is to communicate with your body's other watchdog systems, especially the hormones from your endocrine system and the brain chemicals from your nervous system.

You probably know that avoiding stress can improve immunity, but there are also plenty of less obvious ways. "We're still in the horse-and-buggy era of understanding how the immune system works," Berk says, "but we do have a few pieces of the puzzle. Research shows that when you do simple, everyday activities that make you feel good, you also stay healthier. This is a case of science catching up with intuition." Here are 10 of those ways.

1 Go out and mingle

Your immune system likes it when you spend time with friends. "We have phenomenal data showing the value of nurturing, social support and camaraderie," says neurologist Barry Bittman, M.D., CEO of the Mind-Body Wellness Center in Meadville, Pa. In one such study, researchers exposed people to a cold virus and then monitored how many contacts those people had with friends, family, co-workers and members of church and community groups. The more social contacts the people had - and the more diverse the contacts - the less likely they were to catch the cold. Touch is important too: Giving or getting hugs or other forms of touch can boost the activity of the natural killer cells that seek out and destroy cancer cells or cells that have been invaded by viruses.

2 Listen to Beethoven (or Britney)

Listening to music can boost your immunity, but it has to be music you love. "Something that calms one person might rile another," Berk says. "The trick is finding music that soothes your soul." Scientists at McGill University in Montreal found that listening to music that sent "shivers down the spine" or that gave people chills stimulated the same "feel-good" parts of the brain that are activated by food and sex. "Even better than listening to music is making it," says Bittman, who found that people who took part in an amateur group-drumming session had greatly enhanced natural killer-cell activity afterward.

3 Turn down the volume

Noise hurts more than your ears. Any unwanted and intrusive sound can trigger muscle tension, speed heartbeat, constrict blood vessels and cause digestive upsets - the same response your body has to being startled or stressed. Chronic exposure to noise can lead to even longer-lasting changes in blood pressure, cholesterol levels and immune function. Cornell University research found that women who work in moderately noisy offices produce more of the stress hormone adrenaline and may be more vulnerable to heart disease than women who work in quiet offices. Even worse are unwelcome sounds you perceive as uncontrollable, such as car alarms, barking dogs and P.A. systems. Try to take control over the noise in your environment, even if it means wearing earplugs or asking the restaurant owner or gym manager to turn down the music.

4 Look on the bright side

The immune system takes many of its cues from our thoughts and feelings, so try to keep your outlook upbeat. Years ago, Mayo Clinic researchers found that people who were optimists in their youth tended to live 12 years longer than pessimists. A recent study by Anna L. Marsland, Ph.D., R.N., a psychologist at the University of Pittsburgh Medical Center, found that people who were negative, moody, nervous and easily stressed had a weaker immune response to a hepatitis vaccination than their more positive peers. Negativity is a personality trait that's difficult to change, but if wearing rose-colored glasses can improve your immunity, why not try on a pair?

5 Eat right

Any kind of nutritional deficiency may lead to more frequent and prolonged illnesses. If you starve yourself, your body will think it's under siege and pump out stress hormones. Also, dropping more than 2 pounds per week is hard on the T cells that detect diseased or foreign cells. Best advice: Choose fats carefully (omega-3s are good), get enough protein, eat your fruits and vegetables and drink plenty of fluids. "Dehydration lowers resistance," Berk says. Herbs and supplements that promise to boost immunity do no such thing. In fact, megadoses of some so-called immunity-enhancing nutrients, such as zinc, can backfire, which is why experts recommend avoiding zinc supplements that provide more than 25 milligrams daily. One exception may be echinacea, which seems to lessen cold symptoms' severity.