How to Boost Your Immune System, According to Experts
10 immune-strengthening moves backed by research and recommended by doctors.
With COVID-19 still a threat and the flu, common cold, and other bugs lurking, you want to make sure your immune system is ready to mount a strong defense and keep you from getting sick. “The best strategy at this point is two-fold: both prevention of infection and strengthening the immune system,” Valerie LeComte, DO, an emergency medicine specialist in Southern Colorado, tells Health.
With this in mind, we reached out to doctors and other medical experts to find the top immune-boosting habits they recommend to their patients. Some of these help block the initial infection; others fire up your system so you're able to get better faster if you do come down with something. All are simple and easy to incorporate into your day-to-day routine.
Eat foods rich in antioxidants
"While no food or supplement can 'cure' or even 100% prevent you from catching a virus like the coronavirus or the flu, some foods have been shown to help bolster immunity," Cynthia Sass, Health contributing nutrition editor, told us. Citrus fruits, red bell peppers, almonds, sunflower seeds, walnuts, beans, and garlic all have research behind them to back up their immune-boosting claims, said Sass.
Lisa Ballehr, DO, an osteopathic physician and functional medicine practitioner based in Mesa, Arizona, suggests focusing on color—think dark green, red, and yellow veggies and fruits — to help fortify your system with antioxidant phytochemicals that research suggests fight viruses. Aim for nine to 10 servings a day, she tells Health.
Work up a sweat regularly
Consider this the extra push you need to step away from the couch and onto the yoga mat: a 2019 scientific review in the Journal of Sports and Health Science found that moderate to vigorous exercise can power your immune response, lower your risk of illness, and reduce inflammation.
“Exercising regularly and eating healthy are the most significant factors for your immune system,” Timothy Mainardi, MD, an allergist and immunologist based in New York City, tells Health. Research shows that people who live more sedentary lifestyles are far more likely to get colds or other infectious diseases, he says.
The Centers for Disease Control and Prevention (CDC) recommends squeezing in a minimum of 150 minutes of moderate-intensity aerobic activity a week, or 75 minutes at vigorous intensity. A 15-20 minute at-home workout, jump rope or jog-in-place session, or brisk walk around the neighborhood several times a week are good ways to work some sweat into your schedule.
Score consistent sleep
Maybe you're giving sleep short shrift because you’re overwhelmed by working from home while prepping all your meals. Or you find yourself unable to nod off because of the heart-racing anxiety so many people are feeling right now. We get it, but not prioritizing your shut-eye can have serious health ramifications.
“There’s an association with lack of sleep and getting sick,” explains Dr. Mainardi. Case in point: In one study, “medical and surgical residents who would notoriously work 100-hour weeks during their residencies were at a much higher risk of not only getting an infectious disease, but also reactivation of a past one.”
Also, don't assume you can just catch up on sleep after a night or two of staying up late or tossing and turning. “Research suggests that it does not offer the body any advantages over getting a steady dose of shuteye every night,” says Dr. Ballehr Remember, your body is busy at rest, and it’s designed to sleep when the sun goes down. (Oh hey, circadian rhythm.) “It’s during this time it repairs itself so one can arise feeling renewed,” she adds.
According to the National Sleep Foundation, adults between 18 and 64 need 7-9 hours of sleep per night, while older adults need 7-8 hours, and children and adolescents require even more sleep. Aim for the amount that's right for your age group, and try to be as consistent as possible. Turning in and waking up at roughly the same time every day is healthier than an all-over-the-place sleep schedule.
Wash your hands this many times
You've heard over and over how best to wash your hands since the coronavirus pandemic began. But it bears repeating, because it's just such an easy and effective way to prevent any infection. “Washing your hands is an extraordinarily good way of helping one from getting sick,” advises Dr. Mainardi. Plain old soap and water is all you need, but it’s important to scrub up for at least 20 seconds—the length of singing “Happy Birthday” twice—as the CDC says that’s the minimum time needed to significantly reduce the number of microbes on the skin.
But no matter how good your handwashing skills are, they won't help you evade infection unless you know when to scrub up. “You should do so before and after any type of risky exposure,” says Dr. Ballehr. In other words, after you pee or poop, as well as following a sneeze or cough you shield with your hand. Hit the soap and water before you prepare food, after caring for a sick loved one, treating a wound, or touching any publicly used door handles, knobs, switches, or surfaces, says Dr. Ballehr. If you hands are prone to dry skin, the right moisturizer can help.
Use the right hand sanitizer
If you can’t get to soap and water, hand sanitizer is the next best thing. Just be sure to take a peek at the alcohol percentage first. (Alcohol is the active ingredient working to kill viruses and bacteria.) The CDC recommends using hand sanitizer with an alcohol percentage greater than 60%. (In light of the coronavirus, the CDC also says health care professionals should use hand sanitizer with at least 60% ethanol or 70% isopropanol, two different types of alcohol commonly used.)
The bacteria in your gut may affect your body’s ability to fend off infections, which is why Dr. Mainardi suggests eating foods that contain so-called "good" bacteria, organisms that are beneficial for gut health. Fermented foods and beverages—think kombucha and kimchi—are chock-full of the good stuff. You could also consider a probiotic supplement, or incorporate these recipes into your weekly meal plan.
Just a warning though: it's not known if all probiotic foods and/or supplements are safe for some people who are immunocompromised—those with a chronic illness such as diabetes or HIV, or undergoing chemotherapy, for example. If you have concerns, check with your doctor first before taking any probiotic.
Get enough zinc
Dr. LeComte says the trace mineral zinc is needed by the body to make all of the different cells of the immune system, and for those cells to function properly. “There are multiple studies that show people with low zinc are more susceptible to infection,” she adds. The National Institutes of Health also associates zinc with immune functioning and wound healing.
While you can typically get the daily recommended amount—11 mg for men, 8 mg for women—through whole foods like oysters, red meat, seafood, beans, nuts, and whole grains, Dr. LeComte suggests considering a supplement after talking to your doctor and getting your blood levels checked to see if you aren't getting enough from food alone.
Limit alcohol intake
Moderate alcohol consumption doesn't appear to have any positive effects on your immune system, and binge-drinking (more than four drinks in two hours for women and five for men) has been shown to impair immunity in previous research.
“Alcohol temporarily increases the number of white blood cells, which are the infection fighters, in your bloodstream,” says Dr. LeComte. “But as your liver is clearing the alcohol from your system, your white blood cell numbers fall below normal for at least five hours. And while there does not seem to be any good data measuring white blood cell levels for smaller amounts of alcohol, it is assumed that even one or two drinks can blunt your immune system response.”
As for heavier drinking, a 2015 study review in Alcohol Research: Current Reviews described an association between excessive alcohol intake and a greater susceptibility to pneumonia. More research is needed to clarify the association, but if you’re working hard to stay healthy, it’s best to limit your alcoholic intake—or forgo it entirely.
Start doing acupuncture
Okay, you may not be able to schedule your first acupuncture session until your state's lockdown order has been lifted. But it's something to keep in mind: Research has shown that acupuncture boosts immune function by promoting the release of white blood cells, Stephen Chee, MD, a dual-trained doctor in integrative medicine and medical acupuncture at Chee Integrative Medicine in Beverly Hills, California, tells Health. “Acupuncture also has an anti-inflammatory effect and induces the relaxation response, which is helpful for patients who are understandably stressed,” says Dr. Chee.
To see effective results, Dr. Chee says it’s ideal to go once a week—just make sure the clinic you’re interested in follows guidelines from your local health department to ensure safety.
Dial back stress
Unchecked stress, anxiety, worry, and panic pack a lot of negative health effects, and suppressing the immune system is one of them, says Dr. Chee. Plus, “stress can increase the leakiness of the gut and can help drive inflammation and imbalance in the microbiome,” says Marvin Singh, MD, author of An Integrative Gastroenterologist’s Guide to Gut Health & Longevity. Prolonged stress also drives up levels of the hormones cortisol and adrenaline, eventually inflicting damage on the body.
While we're in a particularly tough time right now, you can still take some small steps to help chill and unwind. Meditation is one strategy; you can also try a mental health app, a stress-busting workout, a catch-up call with a friend. Excessive social media usage might actually increase your stress and anxiety, but screen time watching a movie you love or a binge session of your favorite escapist show will help take your mind off things.
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