8 Best Immunity Boosters

With the pandemic, getting vaccinated against COVID-19 is the most pressing way to help your immune system – the cells, tissues and organs that protect us from microbes and help fight disease – fend off serious illness. But in the long run, how can you continue to bolster your immune system against all the other, more familiar threats it faces?

The best immune boosters don’t suddenly rev up the body’s defenses; they support and optimize them over the long haul. “You want to give the immune system a chance to react in its appropriately designed way. You don’t want to get in the way of it,” says Dr. John McCarty, director of the Cellular Immunotherapies and Transplant program at VCU Massey Cancer Center in Richmond, Virginia.

Overhead view of woman eating Korean style beef and scrambled egg rice bowl with a variety of appetizers in a Korean restaurant


You can help the immune system do its job and boost immune system function by:

  • Reducing stress.
  • Eating a healthy diet.
  • Exercising.
  • Getting more sleep.
  • Minding nutrient intake.
  • Getting recommended vaccinations.
  • Protecting yourself from COVID-19.
  • Limiting alcohol intake and quitting smoking.

Reducing Stress

We experience stress when the brain senses danger and triggers the “fight or flight” mode, preparing the muscles, heart and lungs to get you out of harm’s way.

“Stress works to increase certain hormones, particularly cortisol, which ask the immune system to stand down so they can do the temporary job of addressing the existential threat,” explains Dr. Rachel Franklin, vice chair and medical director in the department of Family and Preventive Medicine at the University Of Oklahoma College of Medicine in Oklahoma City.

But when stress is chronic, it hurts immunity. “If allowed to circulate, stress hormones make the immune system sluggish when faced with a challenge,” Franklin says.

Stress reduction, then, becomes one of the best immune boosters. Ways to reduce chronic stress include:

  • Exercise.
  • Deep breathing.
  • Psychotherapy

Eating a Healthy Diet

When you eat an unhealthy Western diet – rich in refined grains, high calorie items, sugary beverages, fatty and processed foods – you do two things to immunity:

  • You deprive it of the antioxidants and nutrients needed to help the immune system function.
  • You change the gut flora (the microbiome) in the GI tract, home to a significant amount of immune cells. “A Western diet reduces diversity in the gut microbiome and is associated with bad health outcomes,” McCarty says.

Health risks of a Western diet include:

  • Chronic inflammation, a lingering activation of the immune system, even when there’s no threat.
  • An increased risk for chronic disease due to high fat/high sugar diets, such as heart disease and Type 2 diabetes.
  • An increased risk for obesity, defined as a body mass index of 30 of more.

Those consequences affect our ability to fend off harmful microbes. “Obesity increases inflammation. Chronic inflammation and chronic disease make the immune response less effective,” says Dr. Heidi Zapata, an immunologist, infectious diseases specialist and assistant professor at the Yale School of Medicine in New Haven, Connecticut.

You can avoid those problems by adopting a Mediterranean-style diet, which includes lots of immune-boosting foods such as:

  • Fruits.
  • Vegetables.
  • Legumes.
  • Nuts and seeds.
  • Olive oil.
  • Whole grains.
  • Moderate amounts of lean proteins (fish or poultry) and low-fat dairy.


Just like eating a Western diet, living a sedentary lifestyle is associated with:

  • An increased risk for chronic disease.
  • An increased risk for obesity.

The antidote to inactivity’s harmful effect is exercise. It’s one of the best immune boosters because it:

  • Serves as a stress reliever for some people.
  • Reduces the risk for obesity.
  • Reduces the risk for chronic disease.

Exercising regularly also leads to:

  • Better heart and lung health.
  • Improved metabolism.
  • Lower blood pressure.
  • Better blood sugar control.

The recommended amount of exercise is 150 minutes per week of moderate-intensity activity, like brisk walking. “But even people who get a minimal amount of exercise seem to have improved microbiome diversity, which is associated with better health,” McCarty points out.[ 

Getting More Sleep

Sure, you function if you aren’t sleeping enough. But making it a habit leads to:

  • Decreased immune function.
  • Increased levels of the stress hormone cortisol.
  • Chronic inflammation.
  • An increased risk for chronic disease.

Getting enough sleep, especially at night, is one of the body’s best immune boosters. “We know that the number of circulating (and patrolling) immune cells peaks at night,” Zapata says.

Circulating immune cells alert the body to damage so it can make necessary repairs.

How much sleep do you need? “It varies based on age and other factors. Young people need more sleep than older people. Children need 10 to 12 hours of sleep. Adults need six or seven hours,” Franklin notes.

Minding Nutrient Intake

We all need to consume the right amount of nutrients, which are among the best immune boosters. Many nutrients form the foundation of immune health, such as:

  • Omega-3 fatty acids.
  • Vitamin C.
  • Vitamin D.
  • Zinc.

How do they help? Take vitamin C: “We know that vitamin C not only regulates white blood cells, but also helps them do a better job of defending the body from viruses and bacteria. Vitamin C is also an excellent antioxidant. It protects our body from inflammation and the negative effects of an overactive immune system,” says Alexander Michels, a researcher at Oregon State University’s Linus Pauling Institute.

Unless you have nutrient deficiency, a healthy and varied diet is all you need to get your fill of nutrients. What if there’s a gap in your diet? “Taking a multivitamin is not a bad thing,” Zapata says, “but getting vitamins in natural ways, from vegetables or fruits, is more potent.”

Will taking supplements boost immune system health if you suddenly get sick? The jury is still out on that one.

When it comes to vitamin C: “We do know that vitamin C, when taken in advance of symptoms, may reduce the duration of the common cold,” Michels says, “but it’s best to get at least the recommended amounts of vitamin C every day to see the most benefits. At least 200 mg per day is acceptable. The Linus Pauling Institute recommends 400 mg a day from diet and supplement sources.”

Getting Recommended Vaccinations

When the body is exposed to a harmful new microbe, it takes time to build up its defenses. “The immune system isn’t prepared when a new virus or new bacteria get into the body. By the time the body makes the tools to fight it, the body has been damaged by infection,” Franklin explains.

Vaccinations are among the best immune boosters because they give the body the upper hand. “They allow the immune system to preview a microbe signature so the body can work better and faster once it actually encounters a pathogen,”

Some vaccinations are recommended annually, such as flu shots. But check with your doctor to see if you’re up to date on other shots including the vaccines for:

  • Hepatitis A and B.
  • Pneumonia.
  • Shingles.
  • Tetanus.

And make sure kids are caught up with vaccinations for:

  • Chicken pox.
  • Diphtheria, tetanus and whooping cough.
  • Flu.
  • Hepatitis A and B.
  • Measles, mumps, rubella.
  • Meningococcal disease.
  • Pneumonia.
  • Polio.
  • Rotavirus.

Protecting Yourself From COVID-19

The new COVID-19 vaccines, rapidly developed in a worldwide effort, are now priming the immune systems of people who receive them. Two types of COVID-19 vaccines– messenger RNA and viral vector vaccines – are being administered in the U.S.

The Pfizer and Moderna versions are mRNA vaccines. The mRNA vaccines work by teaching our cells how to make a protein, or a piece of protein, that triggers an immune response inside our bodies, according to the Centers for Disease Control and Prevention. By producing antibodies, that immune response protects us from getting infected if the real COVID-19 virus appears.

“The level of immune response to these vaccines is very high,” says Dr. Tom Frieden, the New York City-based president and CEO of Resolve to Save Lives, an initiative of Vital Strategies. “So they’re really effective vaccines. The mRNA technology is stunningly effective.”

The Johnson & Johnson COVID-19 vaccine, most recently approved by the Food and Drug Administration, is a viral vector vaccine. These vaccines use a modified version of a different, harmless virus as a vector to deliver genetic “instructions” to cells in the body to trigger an immune response, according to the CDC. Although somewhat less likely to stave off infection than the mRNA vaccines overall, the J&J vaccine is particularly effective at preventing severe COVID-19 cases requiring hospitalization.

Limiting Alcohol Intake and Quitting Smoking

Smoking and heavy drinking are very harmful to immunity. “Excessive alcohol consumption that leads to liver issues will affect the immune system. In people with cirrhosis and liver disease, I’d in many ways consider them immunocompromised,” Zapata says.

“There’s nothing worse you could do for your immune system than smoke,” Franklin says. “While your immune system should be on patrol looking for something it needs to fight, you’ve instead sent it to your lungs, sinus passages, mouth and throat to fight the poison you just ingested. Your immune system can’t fight battles on multiple fronts and do it effectively,” Franklin says.

Changing these habits are among the best immune boosters.

If you drink, limit intake to:

  • No more than two drinks per day for men.
  • No more than one drink per day for women.