Your immune system is vast and complex, but you rarely think about it unless you’re sick. That’s because when it works well, there’s no reason for you to think about it. It’s only when you need it or when it is struggling to protect you that your immune system is top of mind.
As with all aspects of your health, at least some of your immune function is under your control.
Your immune system is like an army, made up of several different players all joining forces to protect you from illness and disease — both from internal and external enemies. External enemies, called pathogens or germs, include bacteria, fungi, parasites, and viruses. Internal enemies, like cancer cells, are generally your body’s own cells that have changed due to illness or mutations.
The soldiers in this fight include organs such as the spleen, lymph nodes, and thymus. Other players are adenoids, blood vessels, bone marrow, lymph vessels, and tonsils, according to Hopkins Medicine. Your lymph nodes release white blood cells known as lymphocytes to fight infections.
One of the primary ways your immune system works is by recognizing invaders or cells within you that are not of you. This is possible because the system is activated, or called up for duty, when it recognizes antigens, or proteins on the surfaces of invaders such as viruses. When the body sees these antigens it starts what’s called an autoimmune reaction.
Your immune system is also highly intelligent — it learns and adapts. The “adaptive immune system” recognizes antigens it’s seen before and knows how best to fight them. It’s constantly evolving to effectively battle against new and old threats.
There are diseases and disorders of the immune system that make it inefficient. These include primary immune deficiency diseases (PIDDs), allergies, autoimmune diseases such as lupus and type 1 diabetes, cancer, sepsis, and AIDS.
But even if you’re otherwise healthy, you can weaken your immune system with the things you eat, the activities you partake in, and the medicines you take. Keeping your immune system strong is a matter of making healthy choices.
There are several actions you can take (or abstain from) that will help boost your immune system.
Manage psychological stress. When you’re stressed, your body produces a hormone called cortisol. Generally, this hormone works to activate the immune system and provide anti-inflammatory benefits. However, there is evidence that chronic stress can lead to resistance from the immune system. In other words, your body is so accustomed to being stressed, that cortisol no longer triggers the benefits it should.
Evidence of this can be seen in caregivers — people that care for the chronically ill and aging. According to a few studies, the stress experienced by these caregivers leads to a less effective immune system.
Get regular exercise, but not too much. In addition to mediating stress, regular exercise may have additional immune-boosting effects. Scientists are unsure exactly how this happens, but it could be due to the temporary rise in body temperature, the counteracting of stress hormones, or the flushing of bacteria from the lungs. However, when exercise becomes excessive or extreme — say in the case of marathon running — the immune system may be depressed. If immune health is your primary goal, stick with moderate exercise.
Don’t smoke. We know smoking increases your risk of many illnesses and diseases, including heart disease and cancer. However, it can also damage your immune system directly. A recent review on the topic called cigarette smoke “a double-edged sword” that both worsens the unhealthy immune response in diseases and lessens the “normal defensive function of the immune system.”
Certain foods or food components can affect your immune system, but solid research on the topic is hard to come by. Many studies on specific foods are funded by companies and organizations that represent that food, making them less than unbiased.
Eat more fruits and vegetables. Produce is nutrient dense, loaded with vitamins and minerals that make you healthier overall. Some of these components — such as flavonoids, vitamin C, zinc, and carotenoids — may benefit the immune system. Dark green leafy vegetables, berries, brightly colored peppers, and sweet potatoes are good choices.
Eat probiotic foods. Keeping your gut healthy may help you avoid illnesses, from infancy on. Research indicates compounds in probiotic foods could improve immune function. Yogurt and fermented foods are good sources of probiotics.
Add lean proteins. Two amino acids — glutamine and arginine — may enhance immune function, according to research. Amino acids are most abundant in animal protein sources, so stock up on lean proteins like turkey, chicken breasts, lean cuts of beef, and seafood. If you don’t eat meat, eggs, soybeans, chickpeas and other legumes, pumpkin seeds and spinach are solid choices.
Ideally you eat a perfect diet, rich in all of the immune-boosting components mentioned above. But none of us are perfect, and there is some value in supplementing if you’re not getting enough healthy foods in your day-to-day life. Still, food should always be your first choice.
In addition to supplementing your diet to get the full range of vitamins and minerals (including those mentioned above), there are potential immune boosting benefits in these supplements specifically:
Zinc. There are several studies that connect zinc supplementation to lessened incidence and severity of certain illnesses.
Whey protein with branched-chain amino acids. Whey protein supplements aren’t just for packing on muscle — some evidence suggests they can mitigate any negative immune effects of intense exercise. If you go this route, look specifically for a supplement containing arginine and glutamine.
Vitamin E. Vitamin E deficiency is known to disrupt immune function. But even in healthy individuals who get enough of the vitamin, vitamin E supplementation may enhance immunity, according to research.