Want to lower your risk of colds, other infections and even cancer? Plenty of products, potions and pills sold in supermarkets and health-food stores promise to do that by pumping up the immune system. Do they deliver?

Forget them all, says Aaron Glatt, MD, chairman of the department of medicine and hospital epidemiologist at South Nassau Communities Hospital in New York. "For the typical healthy person, there is no product that will boost the immune system," says Glatt, who’s also a spokesperson for the Infectious Diseases Society of America.

However, according to Glatt and other experts there are simple lifestyle measures you can take to shore up your immune system so your body is better able to ward off illness.

Fill your plate with the right foods

According to Cleveland Clinic, the most important nutrients for keeping the immune system in top working order are the eight that follow. Note the foods that are good sources of these nutrients and try to include them in your overall diet on a regular basis. They’ll be more effective if you get them from food rather than supplements, experts say.

  • vitamin C (oranges, spinach, kale)
  • vitamin B6 (bananas, tuna)
  • vitamin A (carrots, squash)
  • vitamin D (salmon, tuna)
  • folate (enriched breads)
  • iron (chicken, seafood)
  • selenium (broccoli, tuna)
  • zinc (lean meats and poultry, baked beans)

Related: The Anti-Cancer Diet

Find your exercise ''sweet spot''

By working out regularly, you can improve your resistance to infections, experts agree. "There are studies to show your immune system will function better if exercise is part of your routine," Glatt says.

In a recent review, Texas researchers found that a single bout of moderately intense exercise enhances the immune system and even increases vaccine response in some patients. Regular exercise may work to help the immune system, experts say, by reducing inflammation, balancing older and younger immune cells and helping lower psychological stress.

Overdo it, though, and you could depress your immune system. For example, elite athletes report having more colds when they train heavily and compete, which experts believe is due to immune system changes.

Related: Can't Get Into the Exercise Habit? Try this Trick

Pare off extra pounds

"Being overweight is bad for your immune system," Glatt says. That's because extra pounds increase inflammation in the body, which in turn is detrimental to the immune system. Inflammation also increases the risk of diabetes, heart disease and other problems.

What's a healthy weight? In general, experts say a body mass index (BMI) of under 25 is healthy. To find your BMI, enter your height and weight here.

Related: Can You Be Overweight and Healthy?

Kick the habit

Smoking does more than damage lungs. Lighting up can damage the immune system, causing wounds to heal more slowly and increasing the risk of getting sick.

The chemicals in cigarette smoke increase production of white blood cells, the body’s infection fighters, according to smokefree.gov. Over time, a constantly high white blood cell count puts you more at risk of heart attack, stroke and certain cancers.

If you drink, drink in moderation

Research shows heavy drinkers have a higher risk of viral and bacterial infections. For example, drinking too much increases the risk of pneumonia and tuberculosis, according to the National Institutes of Health.

Even a single bout of alcohol overindulgence can lower the body's ability to fight infections, an effect that can last for up to 24 hours.

At the same time, moderate drinking has been linked to less inflammation of the immune system as well as improved response to vaccines, studies have found. Of course, if you don’t drink, these findings are not a reason to start. Even moderate drinking has been linked to “increased risk of breast cancer, violence, drowning and injuries from falls and motor vehicle crashes,” according to the Centers for Disease Control and Prevention (CDC). If you do drink, stick to one drink a day if you’re a woman and two if you’re a man, advises the CDC.

Snooze so you don’t lose

If you're sleep deprived, your body responds as if it's under extreme stress, research has found. In one study, researchers compared the white blood cell counts of 15 healthy young men when they had gotten a full eight hours of sleep to when they stayed awake for 29 straight hours. The white blood cell levels were much higher when the men were sleep-deprived.

Previous research has found lack of sleep is linked with increased risks of obesity, diabetes and high blood pressure. Other experts have found that sleep helps keep the immune system healthy, while chronic sleep loss can impair the immune system.

How much sleep is enough? The ideal amount depends in large part on your age, according to the National Sleep Foundation, which issued new recommendations earlier this year.

Related: 7 Surprising Reasons to Get 7 (or More) Hours of Sleep

Stress less

When you're constantly under stress, you can feel wiped out. Chronic stress, research finds, affects the body's ability to regulate the inflammatory response. Experts say long-term stress can change the effectiveness of the so-called stress hormone cortisol to regulate the inflammatory response, leaving you more susceptible to illness when you're feeling overwhelmed, overworked, worried or otherwise anxious. Finding ways to conquer stress can go a long way toward keeping you healthy.

Related: 9 (Almost) Instant Stress-Busting Strategies

Kathleen Doheny is a Los Angeles journalist specializing in health, behavior and fitness topics.