(CNN) As kids return to in-person schooling every year, parents are usually prepared for their children's immune systems to reckon with a few weeks of colds and other illnesses.
Add to that list this year: a deadly pandemic, with some symptoms that can mimic other illnesses. As children head to school now, Covid-19 cases are surging and children under age 12 currently cannot be vaccinated against the virus.
Having a well-functioning immune system supported by lifestyle habits such as eating nutritious foods, exercising and sleeping could help reduce Covid-19 risk, according to guidance from the US Centers for Disease Control and Prevention.
At the same time, no single food will totally prevent someone from catching coronavirus or cure the disease, the World Health Organization has said.
"We do know that people (who are) immune compromised are more likely to contract Covid and to get severely ill," said CNN Medical Analyst Dr. Leana Wen, an emergency physician and visiting professor of health policy and management at the George Washington University Milken Institute School of Public Health. "We don't know the degree to which improving your immunity would ward off Covid in some way. That might make common sense, but we don't have the data to say that that's the case. However, from a common sense perspective, we should be doing everything we can to improve health anyway."
Because the immune system involves multiple functions that take place throughout the body, supporting it requires some basic building blocks, said Julie Stefanski, a registered dietitian and nutritionist and a spokesperson for the Academy of Nutrition and Dietetics. Here are seven ways you can support your child's immune system with hygiene, food, rest and more.
Protecting your child from illness begins with trying your best to prevent him from being exposed to infectious agents in the first place, said Dr. Maya Adam, a clinical assistant professor of pediatrics at Stanford University in California.
"That involves really, really keeping up on the hygiene practices," Adam said. "Handwashing is huge. It's the number one thing that we can teach our kids to wash their hands frequently, as much as their setting allows. And as much as is recommended in their location, follow the guidelines on masking and social distancing. Try and be sensible about not being in large groups, especially if there are potential sources of infection."
Encourage hand washing when your kids get home from school or when they are about to eat, said Julia Zumpano, a registered and licensed dietitian at the Cleveland Clinic in Ohio. Unless it's shower night, have them wash their hands and faces before bed, too, she added.
Children under 12 currently can't be vaccinated against coronavirus but following schedules for other immunizations is critical for all children's long-term health, Adam said. Ask your child's pediatrician what vaccines are necessary for her at this stage of her life, Zumpano recommended.
"(I'm) encouraging parents to trust in the fact that the reason we don't have polio cases, for example, is because a vaccine was introduced for that," Adam said. If and when your children are eligible, getting them vaccinated against coronavirus is key to both keeping them healthy and ending this pandemic.
"The minute that (Covid-19) vaccine is available and approved for under 12, my 11-year-old is going to be one of the first, I hope, to get it, because I think vaccines are part of our general health practice," Adam added. "It's like brushing and flossing our teeth at night. It's like getting enough sleep and eating balanced nutrition."
When it comes to using food to support immune function, one method all these experts advised is balanced nutrition.
"A lot of parents just shudder when they hear it, because there's so much confusion about 'What does that actually mean? What do I need to do?'" said Adam, who is also author of "Food Love Family: A Practical Guide to Child Nutrition." "If you do one thing for your kids in terms of nutrition," she added, increase the variety of fruits and vegetables as much as your budget allows.
Zinc and B, C and A vitamins are a few other micronutrients that help immune cells fight infection, said Dr. Mark Corkins, the chair of the American Academy of Pediatrics committee on nutrition. Zinc-rich foods include oysters, red meat, poultry, nuts and seafood. Foods such as salmon, organ meats, green leafy vegetables and dairy products provide vitamin A. All food groups contain varying levels of B vitamins. And citrus fruits, broccoli, strawberries and tomatoes are rich in vitamin C.
Make healthier food options visible and accessible for kids by having fruits already peeled and on the counter to "catch their hunger" during snack times, Adam said. At dinner, ensure a vegetable is at least present or offered, Stefanski said.
The microbiome in our gastrointestinal tract helps regulate how our immune system works, said Corkins, who's also a St. Jude Chair of Excellence in pediatric gastroenterology and a professor at the University of Tennessee Health Science Center. Foods with microbiome-supporting probiotics include yogurt, kefir, kimchi, sauerkraut and sourdough bread, Adam said.
Stefanski recommended eating foods in their whole forms as often as possible since "gut bacteria is nourished by certain fibers in the diet."
Sleep is when bodies regenerate, so helping your kids maintain a healthy sleep routine is also essential for immune function, Zumpano said.
Young children could relax by being read to or brought along on a slow, outdoor walk before bed, Adam suggested. Older kids might enjoy winding down by listening to meditation app audios or stories.
"Start that routine even an hour before they're supposed to be sleeping so it just helps them transition into that phase better," she added. "I don't think our kids have ever heard the ends of those wind downs because they're asleep by the time it's finished."
Additionally, a room that's dark and cool is most conducive to getting adequate sleep, Stefanski said. The American Academy of Pediatrics has details on how much sleep children need depending on age.
Since research has shown chronic stress is a depressant for the immune system, keeping an eye on your kid's mental health via quality time, discussions during activities and mental health professionals is also important for supporting immunity, Adam said.
"I know this sounds impossible," Adam said, but "if you're going to eat, try and time it so that you can eat with your kids and talk to them. There's a lot of research that's been done on mealtimes and how beneficial that is for kids' mental health, because it gives them a regular forum where they can bring up things. ... It's much less effective to go to a child and say, 'Is anything bothering you?'"
Since exercising releases mood-boosting chemicals, the following reduction in stress can support immune strength, Zumpano said.
"Young kids should be playing mostly, but having them outdoors as much as possible, running around, playing whatever they love doing shouldn't feel like a punishment, but something they can engage in a safe way," Adam said.