Want to know how to boost your immune system? First, it’s helpful to understand how it works and why it’s important. The immune system is the body’s first line of defense against infection and disease. It works to fight everything from cold and flu viruses to serious conditions such as cancer.

“The immune system is a collection of cells, tissues and organs that all work together to protect the body from virus and bacteria,” says registered dietitian Caroline Passerrello, a spokesperson for the Academy of Nutrition and Dietetics and a faculty member in the Dietitian Nutritionist Program at the University of Pittsburgh.

“There are multiple lines of defense that work together to keep our bodies functioning as intended. Some of them fight to keep substances out of the body, and some work to ward off viruses and bacteria that have invaded the body. One line of defense is the mucosal tissue and mucus – this is a sticky substance that works to keep germs from invading our bodies through our noses. Our skin, our largest organ, is another line of defense in the immune system.”

In simple terms, the stronger your immune system is, the less chance of getting sick. Here, our experts explain more about how to support the immune system naturally.

Can you actually ‘boost’ your immune system?

While we’d all love to know how to boost our immune system and never get sick, the truth is, there are no scientifically proven links between lifestyle changes and enhanced immunity.

Immunologist Dr Brian Ferguson, associate professor of immunology at the University of Cambridge, tells Live Science that you can’t really ‘boost’ the immune system. “You can keep it healthy and working effectively with a normal diet and normal levels of exercise, but nothing really ‘boosts’ it,” he says.

Caroline Passerrello

Registered Dietitian

Caroline Passerrello is a spokesperson for the Academy of Nutrition and Dietetics, a faculty member in the Dietitian Nutritionist Program at the University of Pittsburgh, and co-author of Human Nutrition: Science for Healthy Living (3rd edition). Passerrello's teaching focuses on the principles of education, community engaged scholarship, public health nutrition, and personal and professional development skills for registered dietitian nutritionists.

A small study of healthy twins aged between eight and 82 concluded that while genetics played a role, our immunity was mainly determined by non-inheritable factors. The germs we are exposed to throughout our lives, as well as individual lifestyle factors such as sleep, stress, diet and exercise, all play an important role in the strength of our body’s defense system.

Dr Deepak Ravindran, MD, also tells Live Science: "Since the predominant amount of the immune system is around the gut, traditional ways of ‘boosting’ the immune system have been around diet and nutrition and supplements.

"The immune and nervous systems are deeply interlinked, so methods such as mindfulness, breathwork techniques and meditation can also achieve the same impact on the immune system. Relaxation strategies around touch, art therapy, grounding techniques, dance and movement can all have the same impact on calming and boosting the immune system."

How to support your immune system

Being physically active and eating a balanced, nutritious diet are all ways to naturally support the immune system, says Passerrello.

Aim for antioxidants

Proper nutrients are essential to immune function, and they help spur the creation of white blood cells and antibodies, which fight disease. “Antioxidants are components of foods that help protect us at the cellular level – they protect our cells by neutralizing potentially harmful substances that make their way into our bodies,” she says. “Most plant foods are good sources of antioxidants.”

Eat fermented foods

According to Passerrello, inflammation is a sign that our body is using the immune system to try and restore equilibrium. “Our bodies need helpful bacteria to balance out the bacteria in our gut and keep inflammation at bay,” she says. Eating gut-friendly probiotic foods, like yogurt, kefir, kimchi, kombucha and tempeh is a good way to support the immune system.

Vary your sources of vitamin C

Vitamin C is a key component of white blood cells and they play a big role within the immune system and help to fight infection. Cup for cup, red bell peppers have more vitamin C than citrus fruits, so look beyond citrus for vitamin C sources.

Zone in on zinc

“Zinc deficiency can impact both our innate and adaptive immunity because of its role in many different types of cells within the immune system,” says Passerrello. “Example: our lymphocytes are a type of cell that plays a role in immunity. Lymphocyte activity is dependent on adequate levels of zinc. Beef, cereal, shellfish, seeds, and legumes are good sources of zinc.”

Take regular exercise

Regular exercise has been shown to help reduce stress, improve the immune system’s regulation and ‘delay the onset of age-related dysfunction’, according to a study published in the Journal of Sport and Health Science.

Minimize stress levels

“While there are many stressors in our lives that are outside of our individual control, taking steps to manage stress levels will also support a healthy immune system,” says Passerrello.

“There is also a bidirectional relationship between immunity and mental health, a study published in the peer-reviewed journal Clinical and Experimental Immunology found.”

Don't smoke

According to the Centers for Disease Control and Prevention, smoking harms the immune system and can make the body less successful at fighting disease.

Smoking is also known to compromise the equilibrium (balance) of the immune system, which increases the risk for several immune and autoimmune disorders. These are conditions caused when the immune system mistakenly attacks the body’s healthy cells and tissues.

Get good quality sleep

Sleep and immunity have a bidirectional relationship. Your immune response, for example to a viral infection, can affect sleep. And sleep deprivation causes the body to produce more cortisol (the stress hormone), and we’ve already heard that being stressed out can impair our immunity. Meanwhile, good quality sleep can strengthen the immune system.

How does the immune system change as you age?

Immunity, the body’s defense system, tends to get weaker with age, says Passerrello. “We know that the immune system, after working and protecting our bodies for years, decreases in efficiency and efficacy as we age.”

Here’s the thing: not only do you have fewer immune cells as you get older, the ones you do have don’t communicate with each other as well. Put simply, that means they take longer to react to harmful germs and become less efficient at fighting infection and illness.

Unfortunately, there’s no magic pill or one thing we can do or eat that’s guaranteed to boost our immune system and stop us from getting sick. The best we can do is try and take care of ourselves, eat well and exercise regularly to give our immune system its best chance of doing a good job.

This article is for informational purposes only and is not meant to offer medical advice.