You are not defenseless.

If you follow the mass media, you may be under the impression that the only way to avoid getting sick is to hide under your bed and pray. While limiting your exposure is a smart first step to keep yourself safe from any contagion, don’t forget that your body knows how to protect itself. The better you care for your immunesystem, the greater your chances of weathering any germ storm that blows through. The solution to avoiding illness, then, isn’t purely to stow away until it’s safe to come out, but to take an active role in supporting the system that prevents it.

First we’ll look at how your immune system functions, and then we’ll show you the steps to take to keep it online, and running without defects.

How The Immune System Works

How To Support A Strong Immune System

Your body is constantly on the lookout for anything that tries to enter it and shouldn’t. Be it an allergen, bacteria, a virus, or a wood splinter you got from sanding your deck, when your body senses an invader, the immune system is going to kick in to try to get rid of it ASAP.

The first series of defense mechanisms it uses to do that are no doubt familiar to you, and you already think of them as warning signs that you may be getting sick. You start sneezing and coughing. Your eyes water and your nose runs. You find yourself needing to use the toilet more often. Your finger swells up around the site of the splinter, a sign that white blood cells are rushing to the area in an effort to kill any germs that may have come with the particle.

If those initial mechanisms don’t stop the threat, the invading substance can start to get a foothold in your body—and that’s when it can make your life miserable. Viruses bind with healthy cells, using them as hosts to replicate themselves and multiply.Bacteria divide inside the body and take up space that crowds out healthy cells, disrupting their normal functions and potentially killing tissue.

At this point, your immune system knows it needs to take drastic measures, so it turns up the heat—literally. It produces fever-inducing cytokines, the proteins interleukin-1 and interleukin-6, which cross over the blood-brain barrier to signal the brain’s hypothalamus that the body’s thermal set point needs to be raised. This is when your forehead gets hot, and the chills set in—an effort to raise the body temperature by contracting muscles. (You feel cold because your body is colder than the level your immune system is trying to raise it to.) These symptoms make you feel terrible, and they’re sure signs that you’re sick as a dog, but they’re actually playing a vital role in turning the tide of battle. The heat from the fever helps to stop bacteria and viruses from spreading, and can start killing them outright—in effect, cooking them to death. (“The enemy deserves no mercy…”)

The body is mounting its counter-attack. It mobilizes white blood cells—specifically, phagocytes—that engulf the offending bacteria or virus and destroy it. Some of these blood cells develop antibodies, cells that remember the DNA of the invaders so that the body can recognize them and stop them sooner if they should ever come back. This is why it’s difficult to come down with the same virus again if you’ve already had it (e.g., chicken pox). Your body sees the enemy coming from a mile away this time, so it won’t get ambushed like it did before.

Your immune system is an army that will win many wars over your lifetime. But like any army, it is most effective if it has adequate resources, and doesn’t have to fight wars on multiple fronts. Therefore, keeping it fit and well-supplied should always be a priority.

Ways To Help Keep Your Immune System Strong

There are three strategies to promote immune health. None of them—individually or altogether—can guarantee that you’ll never feel badly again, but they’ll do the most possible to keep your army alert and on the field.

#1 Reduce The Workload On Your System

This boils down to simply avoiding stress of any kind, and that includes the type you get from hard workouts as much as it does the grief caused by your boss, your kids, or the flat tire you got driving to work this morning. Of course, exercise is generally helpful in keeping you healthy (more on this in point #3), but if you feel that you’ve been exposed to someone who’s sick, or you’re starting to notice the first symptoms of an illness, lighten up on your workouts or stay home and rest. Hard training promotes an immune response, and if the system is already working to battle back viruses and bacteria, you’re only dividing your forces.

The danger with stress, on the molecular level, comes from a boost of free radicals. These are byproducts of chemical reactions in your body that leave molecules that are missing electrons. Now highly unstable as a result, these molecules are capable of damaging lipids, proteins, and DNA. At normal levels, they serve a helpful role, warning the immune system of incoming invaders, but when they grow out of control, they create mutations in cells, or kill them. Accumulation of free radicals is thought to be a harbinger of serious health problems.

Free radicals accumulate when you consume alcohol, cook food (particularly at high heats with unstable polyunsaturated oils), exercise to excess, are exposed to pollution or radiation (including from sunlight), and suffer any degree of mental stress. Naturally, many of these things are hard or impossible to avoid, so don’t think you have to live like a hermit. Simply limit your exposure to them in large doses.

While you’re trying to evade stress in the short term, you can simultaneously practice methods that help you control it in the long term. As simple as it sounds, spending more time in nature (forest bathing) has been shown to have extremely powerful effects on stress, and may even reduce your risk for specific diseases. Meditation may do likewise. 

But there may be nothing so restorative to your immune system as getting more sleep. A review in Frontiers in Bioscience concluded that sleep attenuates oxidative stress (a result of free-radical buildup) that can cause problems in the brain, heart, liver, and more. And just because you may be young and healthy already doesn’t mean you can afford to stay up all night. A 2018 study found that active physical educationstudents—average age 21—undergoing a short-term survival training course that deprived them of sleep suffered substantial increases in oxidative stress levels. Fortunately, the study also showed that catching up on their sleep afterward helped the subjects return to normal.

#2 Stay Clean

This is an extension of tip #1, but it warrants its own category. Avoid people who are sick and touching things that might be contaminated, and practice good hygiene to reduce the chance of microbes clinging to your skin (and eventually getting through it).

This is where hand-washing comes in. The Centers for Disease Control and Prevention (CDC) say it’s still one of the top ways to avoid coming down with something. And as simple as hand-washing is, you’re probably not doing it the way the government wants you to. Here are the correct steps, according to the CDC.

1. Wet your hands with clean running water. It doesn’t matter if it’s warm or cold.

2. Apply soap. Contrary to popular belief, antibacterial soaps are no better than the conventional kind, so any soap will do.

3. Turn off the tap (to save water).

4. Rub your hands together to lather the soap on them. Don’t neglect the back of your hands or the space between your fingers, and be sure to soap under your nails. Work for at least 20 seconds (about the time it takes to sing the “Happy Birthday” song twice).

5. Turn the tap back on and rinse your hands. Yes, you’ll have to touch the faucet handle again to do it, but the CDC says there’s little reason to worry about contamination from that.

6. Dry your hands with a clean towel (paper or cloth), or air dry them.

Hand sanitizers are another option, but the CDC says they’re only your best chance if you can’t get to a sink. There isn’t much research pitting hand washing against hand sanitizing, but a 2019 study found that simple washing removed the flu virus from hands better than using an alcohol-based gel did. However, the subjects using the sanitizer merely placed it on their skin—they didn’t rub it in, as most sanitizer brands instruct you to do.

Although they’re extreme examples, and mostly relevant when dealing with pandemics, social distancing and quarantine are other effective methods of staying germ-free as well. Surgical masks have been found to be helpful as a barrier, lessening the spread of germs to others when the wearer is sick, but they won’t do much to prevent you from breathing particles in, or contacting them by touch. The U.S. Surgeon General warns not to use them, so that they can be reserved for healthcare providers.

#3 Stimulate Immune Health

What you eat and supplement can make a big difference in your immune responses. For optimal immune health, fruits, vegetables, grains, and mushrooms should be staples in your diet, and the more different colors you can include on your plate, the better. Colorful produce is rich in phytonutrients—plant compounds that have antioxidants (such as Vitamins A, C, and E) or antioxidant-like properties, both of which fight free radicals.

In particular, pay attention to citrus fruits, which are loaded with Vitamin C. One of the best researched and most potent antioxidants, Vitamin C helps maintain cellular integrity—that is, aiding the cell membranes in keeping foreign bodies out. The vitamin is also an important component of blood vessels, ligaments, and bone, helps the body synthesize carnitine (an energy-producing amino acid), and supports the production of neurotransmitters (the body’s chemical messengers).

One type of food you’re almost certainly not getting enough of is mushrooms. Packed with a variety of beneficial compounds, they’re an underrated immune-supporting resource. Mushrooms also offer polysaccharides, compounds that serve as a prebiotic, acting as food for the good bacteria in your gut that eat the bad kind that can get you sick. One polysaccharide in particular, beta-glucan, helps the immune system through another mechanism as well.

Your body doesn’t recognize beta-glucan as food when you consume it. It’s safe to ingest, but your system assumes it’s dangerous. This promotes an immune system response in an attempt to protect you from beta-glucan, just like it was a foreign invader. As a result, your immune defenses go on high alert, and can help neutralize other potential threats to your body before they run you down.

Chaga is a type of mushroom, usually found as a tea or supplement, that should be on your shopping list. It has been shown to be particularly helpful for maintaining cell integrity.

Don’t neglect foods that come as a side, or seasoning for your main dish. Research shows that two commonly used spices, ginger and turmeric, can be beneficial when eaten or supplemented. A review in the International Journal of Preventive Medicineshowed ginger helps the body clear away oxidative stress, while a Journal of Clinical Immunology review indicated that, thanks to its curcumin content, turmeric’s ability to promote immune system function is “beyond doubt.”

The way you prepare your food can greatly impact its health potential. Vegetable oils consisting of polyunsaturated fats are not stable at high temperatures, and will oxidize when you cook with them, creating free radicals. Saturated fat sources, such ascoconut oil, MCT oil, and butter, remain stable at high heat, and are therefore better choices (123). Furthermore, coconut oil and MCT oil contain antimicrobial and antifungal properties that may help support immune resistance as well.

This isn’t to say that all microbes need to be killed off. Remember that there’s good bacteria too, and the type that live in your gut have a major say in how your immune system works. As a matter of fact, some 70% of the body’s immunity-supporting cellsreside in the gut. Called probiotics, you can boost their number by eating more fermented foods, like yogurt, or taking probiotic supplements. Probiotics help maintain immune health by gobbling up pathogenic bacteria and enhancing the quality of your body’s mucus, in effect, creating a better trap for invaders to get caught in, and then flushed out by. One powerful probiotic technically isn’t a probiotic at all, but functions like one. Saccharomyces boulardii is a yeast found in lychee fruit and mangosteen, but is more readily available in supplement form. It helps the body produce antibodies (the cells that prevent you from getting sick again from the same invaders), and  supports communication between cells in the immune system, allowing for a better-orchestrated immune response.

Lastly, working out—in addition to all the good it does your muscles, heart, bones, and connective tissues for overall longevity—plays several roles in keeping you out of a sick bed. Though not conclusively proven, scientists at the National Institutes of Healththeorize that physical activity may help flush bacteria out of the lungs and airways, cause white blood cells to circulate more rapidly, and slow down the release of stress hormones. The brief but significant rise in body temperature you get from exercise may also help prevent bacteria from multiplying—similar to a fever.

So, unless you’re already sick, keep exercising!