As the novel coronavirus spreads around the world, so is a lot of misinformation about how people can protect themselves. Predictably, the pandemic has brands and influencers聽 nutritional supplements and other products that they claim can give聽immune systems a quick and easy 鈥渂oost鈥 to ward off this聽coronavirus and the resulting disease, COVID-19.
Such marketing often exasperates聽immunologists,聽who stress that it鈥檚 not really possible to boost聽otherwise healthy immune systems, explains , an immunologist at the UK鈥檚聽University of Manchester. Nor is that something you鈥檇 want, even if it were a possibility: when people develop severe forms of COVID-19, many聽experts 聽it鈥檚 because their聽immune systems聽are聽spiraling into overdrive and overwhelming their聽bodies.
We just need the nuts and bolts of our immune machinery to work normally. People should strive to have a healthy baseline, says , a virologist who studies coronaviruses at the University of North Carolina at Chapel Hill. 鈥淚f they do unfortunately get infected, they鈥檒l be in the best possible situation to fight off this infection and stay healthy,鈥 she says. Thankfully, there are some solid, science-backed ways to do that.
Get Moving
The first item on the list won鈥檛 surprise you: exercise. overwhelmingly agree that people who exercise regularly are less likely to develop seasonal colds and flus, explains , an exercise physiologist at the Human Performance Laboratory at Appalachian State University. For instance, in a 2011 , Nieman and his colleagues tracked over 1,000 adults through the fall and winter 补苍诲听monitored whether they caught a cold聽and how many days they were sick. They found that those who were most physically active鈥攄oing at least 20 minutes of walking, cycling, or other exercise five or more times a week鈥攔eported 43 percent fewer sick days than those with largely sedentary lifestyles.
Muscle contractions increase blood flow and raise body temperature, which are both thought to mobilize immune cells that are usually tucked away in our spleens or lymph tissues. The group of immune cells that surge during and after short bouts of exercise, which include聽 and cells, serve as our frontline defense against invading viruses.
It鈥檚 a transient effect, though, so regular exercise is important. (For people in locked-down parts of the world, there are a lot of options for at-home workouts.)听
However, it鈥檚 possible to have too much of a good thing. After an hour or so of high-intensity exercise, the body starts to suffer from stress, which can impair immune function. Elite athletes can be particularly susceptible to falling ill, so don鈥檛聽push yourself too hard. And obviously, for those who are already sick, that鈥檚 the聽time to rest, not聽exercise, Nieman聽adds.
Eat Whole Foods
The second step toward聽a happy immune system is eating a healthy, balanced diet with plenty of fresh vegetables and fruit. Since your聽grocery trips聽may be few and far between, it鈥檚 advisable to buy frozen fruits and veggies and more shelf-stable items, like apples, oranges, and sturdy greens, to hold you over until your next outing.
The emphasis here is on balanced,聽Cruickshank explains. Immunologists don鈥檛 know of any one food that does the trick. Not only does a diverse diet provide the vitamins and minerals that immune cells need to function normally, but it鈥檚 also good for the bacteria that live in the gut, which play an role in keeping your immune system working properly, she adds. Do your best not to drink too much, either鈥攁lcohol is to poor immune function.
There鈥檚 little conclusive evidence that聽nutritional supplements like vitamins, iron, or zinc substantially improve immune function. A recent of 25 clinical studies on聽vitamin D,鈥嬧嬧嬧 which included over 10,000 patients, did show that the vitamin has a modest effect in protecting against colds. But there was a lot of variation across studies: some showed no effect whatsoever, explains聽, an immunologist at Queen Mary University of London. It may only be useful to supplement if you are deficient in the vitamin.听
Generally speaking, if you鈥檙e getting enough vitamins from your diet, supplements are unlikely to help much, Nieman says. In previous research, he and his colleagues tried giving large doses of聽 补苍诲听 supplements to elite athletes. Neither produced much of an improvement in immune function. 鈥淭he body doesn鈥檛 work that way,鈥 he explains. 鈥淚鈥檇 tell people to be very wary of any pill or capsule that contains something that supposedly will magically boost the immune system to do its job better.鈥
Give Your Brain a Break
骋别迟迟颈苍驳听enough sleep could help, too. In by Carnegie Mellon University professor聽 and others, people who got less than seven聽hours of sleep a night were more likely to develop a cold when the researchers exposed them to a cold-causing virus鈥攁 finding by other studies.
Managing may also聽be important. Another of Cohen鈥檚 showed that those who reported more stress in their lives were more likely to develop cold symptoms. One reason for this effect is that the stress hormone cortisol can certain parts of the immune system, Cruickshank says. She recommends simple practices like spending time in nature聽(if possible) and appreciating聽small things.
A lot of these habits are understandably difficult to maintain in the midst of a pandemic. And scientists aren鈥檛 entirely sure whether this advice will necessarily help against this particular coronavirus, since studies have largely focused on less harmful pathogens.听However, many health professionals聽agree that following sane advice to keep our immune systems healthy鈥攅ngaging in moderate exercise, eating a balanced diet, and avoiding stressing out鈥攊s probably our best bet. And that鈥檚 not a replacement for the stuff that can help stop COVID-19 from spreading: washing your hands, staying at home, and keeping up with the latest .