9 ways to boost your immunity

Your immune system is a bit like a car. You enjoy its benefits without thinking much about how it works—until something goes wrong. Like a car, your immune system has many moving parts, which means it requires maintenance. At a basic level, your immune system protects you from germs like bacteria, parasites, and viruses, preventing infections.

Most people are familiar with the idea that white blood cells are a key part of your immune system, but they’re not the only piece of the puzzle. Your immune system has many specialized cells, tissues, and organs. So, how do you keep your system running smoothly so you can go about your day? Here are nine science-backed methods to support a healthy immune system.

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Certain foods can influence immunity. While eating a healthy diet can keep you feeling good, packing in the leafy greens has been scientifically proven to improve immune function (Li, 2011).  

Certain fruits and veggies, especially those with dark pigments like pomegranates, blueberries, and more, contain antioxidants, which help your immune system by hunting down something called free radicals. Free radicals are toxic byproducts that can damage your cells, leading to things like cancer, and boosting your antioxidant intake can help on that front (Huang, 2018). 

Eating the right foods won’t help you if you're not eating enough, however. Undernutrition and nutrient deficiencies can impair your immune system (Marcos, 2003). If you want to give your immune system the biggest leg up through nutrition, eating plenty of antioxidant-rich foods and consuming adequate calories is a good place to start.

Regular exercise offers countless health benefits. One review of the relationship between exercise and immunity found that working out can help prevent illness in several different ways. Moderate exercise is associated with a lower risk of illness, and exercise in general increases immune defense activity in the body. You'll reap more rewards if you make working out a habit, too. A consistent exercise regimen helps the body regulate the immune system and may even improve the imbalances that can happen in this critical system as we age (Nieman, 2019).

While some researchers believe that immune function can decrease immediately following a single workout session (by reducing the number and function of lymphocytes, a type of white blood cell that plays a crucial role in immune function), that’s up for debate. One review suggests that these studies have been misinterpreted, reporting that this dip in the number of lymphocytes after exercise actually means the white blood cells are just redistributing to where they’re needed, perhaps even improving immune function (Campbell, 2018).

But athletes and people who train intensely for fun, take note: Researchers did find that extended bouts of intense exercise, such as preparing for a competition, do, in fact, take a toll on immunity. So while the occasional intense workout gets a pass, long stretches of extreme training are associated with bouts of illness—especially in females and endurance athletes (Nieman, 2019). Moderation is key.

It's not just your imagination that you always get sick after a big work project or bout of stress-related sleeplessness. People who are sleep-deprived are much more likely to catch the common cold than those logging adequate hours in bed, one study found. Those with the best immune response were getting more than seven hours of sleep per night, while those sleeping fewer than five hours a night were at high risk of getting sick (Prather, 2015).

Although they're certainly no replacement for an all-around healthy lifestyle, there are some supplements with scientific backing for their ability to support a healthy immune system. But there are a couple of things to unpack here. First, deficiencies in certain nutrients may cause your immune system to suffer—but that doesn't mean taking extra when you have healthy levels will have a positive effect. Vitamins and minerals that play a role in the immune system include (Maggini, 2007):

• Skin barrier: vitamin A, vitamin C, vitamin E, and zinc 

• Antibody production: vitamin A, vitamin B6, vitamin B12, vitamin D, vitamin E, folic acid, zinc, copper, and selenium

• Cellular immunity: vitamin A, vitamin B6, vitamin B12, vitamin C, vitamin D, vitamin E, folic acid, iron, zinc, copper, and selenium

A balanced diet that provides adequate calorie intake should get you close to meeting your nutrient needs, but taking a multivitamin is another option if you can’t meet your daily needs.

While we all know that excessive drinking isn't healthy, we often think of liver damage as the primary physical consequence. But drinking too much alcohol has long been associated with an increased risk of illness and death from infectious diseases such as pneumonia.

But we're suggesting moderation here and not abstinence. Moderate drinking of polyphenol-rich beverages such as wine and beer has actually been found to slightly benefit the immune system compared to avoiding alcohol altogether (Romeo, 2007b). One small study found that moderate beer consumption—as defined by one 11.2-oz beer for women a day and two 11.2-oz beers a day for men—had a positive modulating effect on the immune system, though women benefited more than men (Romeo, 2007a). More research needs to be done on the exact amounts that support immunity, as well as whether certain drinks have different effects (Romeo, 2007b).

Although a review on the research surrounding tobacco use and immunity underscored the need for more studies on the topic, it did find that there's evidence that smoking can cause changes to several parts of our innate immunity. 

Tobacco use may change the tissue surface of our lungs, as well as several types of our immune cells. Based on the summary of research in this area, the authors of the review emphasize that quitting smoking should be recommended for everyone, but in particular for people who struggle with recurrent infections and anyone who is immunocompromised (Mehta, 2008).

Sunlight has multiple effects on our immune system. Ultraviolet (UV) light, the reason why you should be wearing sunscreen, can cause cancer. But sunlight also benefits the immune system because it aids in the synthesis of vitamin D, which supports antibody production and cellular immunity (Maglio, 2016; Maggini, 2007). 

But that doesn’t mean you should head for the tanning beds. Instead, if you have a vitamin D deficiency, you can make sure to pack it into your diet. If eating foods high in vitamin D isn’t enough, there are supplements available that can help.

Washing your hands is one of the simplest, most effective ways to protect your immune system. One study even compared handwashing with soap and water to products like hand sanitizer and found that handwashing was more effective at removing viruses (Hirose, 2019).

You should wash your hands with soap and warm water for at least 20 seconds after using the restroom, after coughing or sneezing, and before eating or touching your mouth, nose, or eyes.

You should be getting the flu vaccine annually. Studies have found that the vaccine reduces the risk of hospitalization due to the flu in children and death in adults (IDSA, 2019). It’s also important to get the COVID-19 vaccine and keep up to date on current developing guidelines to ensure that you and the people around you are protected. 

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Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

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Current version

November 03, 2021

Written by

Linnea Zielinski

Fact checked by

Yael Cooperman, MD

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About the medical reviewer

Yael Cooperman, MD, Ro

Yael Cooperman is a physician and works as a Senior Manager, Medical Content & Education at Ro.