Shot of a young woman suffering from a headache and feeling sick on the sofa at home

What You Really Need to Do to Boost Your Immunity

You’ve seen the dodgy ads at the bottom of web pages for pills, drinks, and super foods that promise to boost your immunity. Is there any truth to these claims?  

“It’s important to know that these products—and activities like cold-water plunges—have not been shown to enhance immunity or increase your protection against infection,” says pediatric immunologist Joshua Milner, MD, professor of pediatrics at Columbia University Vagelos College of Physicians and Surgeons.

“A lifestyle that includes eating healthy foods, physical activity, reducing stress, and getting enough sleep is known to keep your immune system in the best shape,” adds Milner, who is a leader in the discovery of rare immune deficiency disorders of children. 

The immune system 

Your body’s immune system—a collaboration among organs, cells, and proteins—fights off germs to protect you from getting sick. The immune system changes through the lifespan as people are exposed to bacteria, viruses, and other microbes. These exposures, and exposures via vaccines, teach the immune system to recognize the germs later in life and eliminate them. 

Weak immune systems 

It is almost never the case that your immune system is completely weak, says Milner. Most often, only a small part of the immune system is weak, which makes infections from specific, not all, bugs more likely. Some people have stronger immune systems than others, so they are resistant to more types of infections. A few people, very few, are resistant to all types of infections.  

How to know if your immune system is weak or strong 

Unfortunately, most people find out that one part of their immune system is weak when they get an infection. But there is no single test that checks out the immune system.  

Age plays a big role in the immune system. Young children, exposed to infections for the first time, tend to be symptomatic more than adults. And older adults may find their immune system cannot fight disease as well as it did when they were young. 

How to boost your immune system 

Scientists are studying direct connections between lifestyle choices and strong immune systems. What we know now is that healthy living is good for overall health and vaccinations are the best supplement available. Most studies show that dietary supplements are only useful if you have a deficiency in a nutrient. Taking supplements on top of a healthy diet does not add much to your immune system.   

How to keep your immune system strong

Milner recommends:

Eat as many fresh fruits and vegetables as you can, every day.

The micronutrients they provide ensure you aren’t missing key nutritional components, like zinc and vitamin A, that your immune system needs to fight off invading microbes. Note that most supplements are not superior to the nutrients you can get from food. 

The fiber from fruit and vegetables can help your gut’s microbiome produce important compounds for a healthy immune system. 

Stay physically active with walks and exercise.

Studies show the immune system is very responsive to exercise. Exercise and immune regulation are interrelated and affect each other. Exercise changes immune regulation by affecting cells and has anti-inflammatory effects. 

Sleep for at least seven hours a night.

When the body does not get enough sleep, the immune system is negatively affected.  

Sleep loss reduces natural killer cell activity, which increases the risk for cancer and viral infections; generates production of inflammatory cytokines, which increases the risk for cardiovascular and metabolic disorders; and reduces production of antibodies, which increases the risk for infections. 

Minimize stress.

Stress of all sorts—psychological and physical—directly weakens parts of your immune system, increasing risk for infections or reactivation of viruses inside you. Shingles, a painful rash that arises from the reactivated chickenpox virus, often flares up when people are experiencing chronic stress. 

Stress can also cause "patrols" in your immune system—certain cells that tell the immune system to wind down an attack—to fail. When this happens, too much inflammation can occur. Hives are one example of a stress-induced breakdown in the immune system’s patrols.  

Drink less alcohol.

Alcohol disrupts immune pathways that can impair the body’s ability to defend against infection, contribute to organ damage associated with alcohol consumption, and impede recovery from tissue injury.  

Do not smoke.

Smoking exacerbates pathogenic (disease-causing) immune responses and/or reduces immune defenses. 

Get recommended vaccines.

Vaccines, also called immunizations, teach the immune system to make antibodies that fight off infections before they make you sick.

Ask your doctor about zinc.

Taking zinc supplements at the beginning of a respiratory infection can reduce the severity and duration of symptoms. Ask your doctor to recommend brands and appropriate dose for you.


Joshua Milner, MD, is director of the Division of Pediatric Allergy, Immunology, and Rheumatology and professor of pediatrics at Columbia University Vagelos College of Physicians and Surgeons. He is a leader in the field of discovery and immunopathogenesis of genetic diseases that lead to allergic symptoms.