7 Ways to boost your immune system (proven by science)

Sachin Oza always seemed to catch whatever cold and flu germs were flying around. Despite being only in his mid-thirties, he felt out of shape and out of sorts. He realized that if he didn’t make some changes, his immune function would continue worsening with age. “I have a family background of diabetes, high cholesterol, and heart disease,” says Oza. “I had to take action.”

But Oza’s lifestyle stood in the way. He clocked long days working in finance in London, with little opportunity to be active or focus on his wellbeing. His commute from his home in Orpington, Kent, to the office was stressful and time-consuming, and he was spending far too many hours stuck behind his desk.

Sitting at a desk all day can be surprisingly bad for us

Oza’s increasingly sedentary lifestyle had repercussions. In addition to catching bugs easily, he didn’t sleep well, his body ached, and he felt lethargic. “My immune system was really weak,” recalls Oza. “I knew that I shouldn’t be feeling this way before even hitting 40.” 

So began a 15-year journey to overhaul his health. He implemented some changes to his diet, introducing more raw fruits and vegetables, and cutting down on junk food. He started going for runs, and began interval training, resistance training, and stretching. He also became interested in mindfulness, practicing deep-breathing and meditation.

Now 49, Oza feels like a new man. “I catch colds far less frequently than before,” he says. His aches and pains have eased, his stress levels are lower, and he sleeps soundly. “I no longer wake up in the early hours, which has made a huge difference in how I feel.”

There are many factors affecting the immune system that we can’t control—aging weakens our immune function, for example, and we have individual genetic differences that affect how we deal with disease. Malnutrition (from a dwindling appetite or a disorder like celiac disease) or physical immobility (due to bedrest or a temporary injury) also impair our immunity.

In addition, sometimes a weak immune system is a red flag for more serious medical conditions or other problems that should be looked into by a doctor. They can include recurring digestive issues, getting unusual illnesses that those close to you don’t catch, having slow-healing scrapes and cuts, and catching new illnesses before you’ve recovered from the previous ones. 

A weak immune system can be a red flag for other conditions

Still, Oza has reason to be hopeful that he’ll combat diseases better as he begins his sixth decade. As scientists are discovering, certain lifestyle changes can improve the body’s ability to fight illness and infection. 

Our immune function is incredibly complex. “We’re still struggling to understand it,” says Dr Donald Vinh, an infectious-disease specialist and medical microbiologist at McGill University’s health centre in Montreal. “We’ve made progress in the last 50 years, but it’s a young field.”

Compared to the cardiovascular system or respiratory function, the human immune system has a plethora of nuts and bolts. These include antibodies, organs, proteins, and enzymes. There are also lymphocytes, a type of white blood cell, which include natural killer cells (these attack infected cells) and memory cells (B and T lymphocytes designed to remember and do battle with a germ if it ever returns). Aspects of our immune system are found throughout our bodies, from our skin to our brains. Even the mucous in our lungs and the acid in our stomachs are part of our body’s defences.

All of these moving parts complement each other. Some are tools we’re born with, already primed to recognize and attack certain invaders (this is known as innate immunity). Others are instruments for figuring out how to defend against bugs we encounter for the first time, called adaptive immunity.

Because of this complexity, anyone seeking a quick fix or miracle pill is out of luck. “People think they can just boost the immune system as if it were a muscle, but it’s far from that simple,” notes Dr Vinh.

But like any bodily function, immunity works best when we support our general health—and researchers around the world are getting closer to exposing more links between the choices we make and how well our immune systems work. Here are seven practical approaches that are proven to show some results. 

Take your shots

When it comes to powering up the immune system, vaccines are the most important breakthrough in history. Childhood vaccinations, for instance, have been a key factor in our longer lifespan today. Even before Covid-19, vaccinations against diseases like flu and measles were saving four to five million lives a year, according to the World Health Organization. “Vaccines don’t fix all problems, but they’re profoundly effective,” Dr Vinh says.

Getting your vaccines is super important for your immune system

A vaccine provides a training session for our adaptive immunity, showing it how to fight an invader it’s never seen before. “After the vaccine, you’ll have antibodies already made, so when you see the bug, you’re pre-armed and ready,” Dr. Vinh explains, adding that researchers are developing drugs to try to boost innate immunity, as well.

Watch what you eat

Inflammation, a chemical cascade that’s a critical part of our immune response, also has a dark side. When it’s helping, inflammation traps viruses and bacteria by triggering fluid and swelling. It also aids in healing by calling for a cleanup crew of specialized white blood cells called phagocytes. 

But inflammation is also triggered by glucose and fats, and if it’s constant, it can wreak havoc on your body—causing health problems such as diabetes, liver disease, and cardiovascular disease. Refined carbs, like white flour, and sugar-sweetened drinks have long been linked to higher levels of inflammation in the body.

“Having junk food once in a while isn’t going to impact your health,” says Charlotte Debeugny, a registered nutritionist in Paris. “But if it features consistently in your diet, you’re in danger of it replacing the healthier foods and nutrients that you need for your immune system.”

Many studies draw a connection between nutrition and immune function. In 2021, Harvard researchers rated the eating habits of almost 600,000 people and found that those whose diets placed the most emphasis on plant-based foods had a 41 per cent lower risk of getting severely ill with Covid-19 compared to those with the worst diets. 

Should we use dietary supplements? For most of us, even as we age, a balanced and varied diet gives us most of the nutrients and micronutrients we need. But in rare cases, vitamin deficiencies can interfere with immune function. If you’re vegan, you should take a vitamin B12 supplement, and if you aren’t getting a lot of sun exposure, you may require vitamin D. To determine if you have a deficiency, get a blood test.

Get moving

It’s been established that people without much mobility, or those who never exercise, have less resistance to bugs. Regular moderate physical activity, on the other hand, optimizes immune function. And it doesn’t take much. A US study of almost 50,000 people with Covid-19 infections found that those with inactive lifestyles had a higher risk of hospitalization, while people who exercised, even a bit, were more likely to get better on their own.

Doing regular exercise is good for your immune system

In an experiment published in 2018 by Duke University’s School of Medicine in the state of North Carolina, inactive seniors with rheumatoid arthritis improved their innate immunity and lowered inflammation by adding 30-minute exercise sessions three times a week. Researchers are looking into why, but in 2021 a paper in Nature revealed a clue, showing that walking and running stimulate the production of B and T lymphocytes in the bones. 

Avoid going to extremes, though; some research shows that prolonged, marathon-style physical exertion may disrupt our normal immune function. Aim for 10 to 30 minutes of exercise every day to get the immune benefits. 

Oza, who today runs an oil and gas company, has built daily activity into his routine. “I now work from home, which makes it much easier to fit exercise into my day,” he says. “I run four times a week.”

Drink less alcohol and more water

Alcohol negatively affects the immune system in a variety of ways, according to the Canadian Centre on Substance Use and Addiction. Excessive drinkers, for example, can have a higher risk of pneumonia and they take longer to recover from injuries and infections. 

If you’re a regular drinker, Debeugny suggests trying lower-alcohol brands, having a glass of water after each drink, increasing the ratio of soda water in your mix, and having alcohol-free days, noting: “Sometimes it’s best just to say ‘Tonight, I’m not drinking.’ In France [according to the country’s public health agency], it’s recommended that you have at least one alcohol-free day a week to give your liver a break.”

Harness your mind power

When a burst of fear or anxiety does what it’s designed to do, our bodies are flooded with hormones that help us fight or flee—by raising our heart rate and blood pressure to circulate oxygen, for instance. This is called the sympathetic response. Then our parasympathetic response kicks in, slowing our heart rate and relaxing us. But chronic stress—from financial worries, say—means those hormones keep building and circulating, which is unhealthy. 

Chronic stress can sap our defences and destroy immune cells. A 2021 study at Western University in Ontario, Canada, for instance, showed that one type of stress hormone, called glucocorticoids, can reduce the function of a class of T cells that fights cancer.

Relaxing activities like meditation can help you to destress

Dr Catherine Wikholm, a clinical psychologist in Kent, UK, suggests that any short break from constant stress will help. “Do some activities that help to release physical tension and leave you feeling relaxed and recharged,” she says. “Singing, dancing, and laughing are great for reducing stress and boosting our immune system.”

You can also train yourself to induce physical relaxation in your body. Try deep breathing or, better yet, do an online search for guided relaxation and learn how to clench and release muscle groups. “Deep breathing is both simple and effective,” says Dr Wikholm. “It can reduce levels of stress hormones and slow down the heart rate.”

Hit the hay

A consistently good sleep of seven to eight hours each night lowers our risk of infection and chronic inflammation. Just like exercise, sleep affects immunity in ways that are many and varied. 

One recent study at Toronto’s Sunnybrook Research Institute found that seniors with more sleep disruptions scored lower on cognitive tests but also had immune differences; on later brain autopsies, there were unhealthy changes to their microglia, immune cells in their brain tissue responsible for removing debris and battling infection.

Unfortunately, people tend to have more trouble sleeping after about age 55 because their body clocks don’t work as well. “Keeping your sleep schedule consistent is one of the most important things you can do,” says Dr Wikholm. “Go to bed at around the same time each night and get up at a similar time each morning. Getting your body used to a routine makes it easier to fall asleep quickly, therefore maximising the amount of sleep you get.”

Breathe fresh air

Time outdoors gives you a break from indoor air, where infectious bugs may circulate, but it also has benefits for your immune function. A bout of sunlight during the day improves your sleep rhythm at night and allows your body to produce essential vitamin D. 

Fresh air is good both for your physical and mental health

And it may do even more: In 2016, researchers at Georgetown University Medical Center in Washington, DC, demonstrated that the sun’s rays increased the activity of T cells. Going outdoors usually leads to getting some exercise, and it’s even been shown that exposure to natural environments reduces stress and anxiety.

In addition to maintaining a balanced diet and a consistent exercise regimen, Oza makes a conscious effort to spend more time outside. As time goes on, he has become even more convinced of the health benefits of the changes that he has implemented over recent years. All in all, he is gratified with his new life. 

“As I enter my fifties, my immune system is in better shape than ever. Changing my lifestyle is one of the best things I have ever done.” 

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