How To Build Up Your Kid’s Immune System

Eat the right foods, and get plenty of sleep and exercise
child holding orange with milk, strawberries and green banana in background.

When your kids are starting a new school year and heading back to the classroom, immunity is always a big concern for parents as cold and flu season looms ahead.

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With COVID-19 still circulating this fall, getting vaccinated and following guidelines for good health hygiene are a start.

But kids and toddlers still need certain nutrients and vitamins to help boost their immune systems to aid in protecting against all the other germs they’ll face, either in the classroom or at home.

Knowing the best foods that can help boost immunity can assist you when meal planning for your child, whether that’s mealtime or an afterschool snack.

We spoke with registered dietitian Julia Zumpano, RD, about the best things for kids to eat and drink to help charge up those immune systems and avoid the typical coughs and sniffles of the school year. 

Can you boost immunity with supplements?

In some cases, supplements can be an immune booster for kids. These are the supplements that are verified by third-party vendors, Zumpano says. “That means, another party has come in and checked that vitamin to verify its quality,” 

But in general, “we really encourage food, not supplements,” Zumpano says. “Supplements aren’t regulated in the U.S. And because there’s no regulating body around these supplements, we’re not 100% sure a supplement is actually giving us what it claims.”

There are times, though, when supplements make sense. “Maybe you’re dealing with a picky eater or you’re struggling with a kid’s diet to get them the nutrients they need,” Zumpano says. “In those cases, supplements can help.”

Boost immunity with vitamin D

While your kids can get most of their vitamin D by soaking up sunshine, that’s harder to do when using sunscreen, during the cooler months and during the school year. Foods that provide the highest amounts of vitamin D also aren’t on a kid’s typical menu. These include fatty fish (like trout, salmon, tuna and sardines) and mushrooms. 

Fortified foods such as milk, yogurt, orange juice and non-dairy milk alternatives (like soy or almond milk) provide about 5% to 25% of the recommended daily value (RDA) of vitamin D, Zumpano notes.

However, she adds that as vitamin D is a fat-soluble vitamin, it’s absorbed best when taken with fat. Keep this in mind when your kids are consuming vitamin D. If a food already contains fat naturally (for example, fatty fish and whole milk), it’s not a concern. When a food doesn’t (like orange juice or some dairy alternatives), you’ll want your kids to pair it with a meal or snack containing fat.

Are vitamin D supplements needed?

A supplement might be necessary if the level of vitamin D in your child’s blood is below the normal range. But there’s some disagreement over the parameters of a normal range. Generally, kids are considered to have a vitamin D deficiency when their blood value is below 20. But some health data indicates that anything above 12.5 is considered safe, while others claim values below 30 are considered insufficient.  

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If you’re concerned your kid’s vitamin D levels are low, Zumpano suggests getting a blood test. You and your child’s pediatrician can determine the best next steps based on the results, including what dosage of a vitamin D supplement might make sense.

The amount of vitamin D you need each day depends on your age. Average daily recommended amounts for kids and adolescents are listed below in micrograms (mcg) and International Units (IU):

  • Birth to 12 months: 10 mcg (400 IU).
  • Children 1–12 years: 15 mcg (600 IU).
  • Teens 13–19 years: 15 mcg (600 IU).

Boost immunity with zinc

One of the most important minerals that can help a kid’s immune system is zinc, Zumpano says. “It’s typically found in protein-based foods. So oysters, red meat and poultry are some of the best sources.” 

Beans and nuts are also a good source of zinc, she says, though the animal-based foods will deliver more of the mineral. 

According to the National Institute of Health (NIH), the recommended daily intake of zinc for kids is:

  • Birth to 6 months: 2 mg.
  • Infants 7–12 months: 3 mg.
  • Children 1–3 years: 3 mg.
  • Children 4–8 years: 5 mg.
  • Children 9–13 years: 8 mg.
  • Teens 14–18 years (boys): 11 mg.
  • Teens 14–18 years (girls): 9 mg.

But be careful — the NIH also notes it’s possible to have too much zinc, which can result in nausea, vomiting, loss of appetite, stomach cramps, diarrhea and headaches. According to the NIH, the upper limits of daily zinc intake are: 

  • Birth to 6 months: 4 mg.
  • Infants 7–12 months: 5 mg.
  • Children 1–3 years: 7 mg.
  • Children 4–8 years: 12 mg.
  • Children 9–13 years: 23 mg.
  • Teens 14–18 years: 34 mg.

Boost immunity with probiotics

Zumpano says it’s also important to give kids a good source of probiotics. “Our gut harnesses a tremendous amount of bacteria. Some are healthy and some are not, and probiotics help create a better balance of that healthy versus unhealthy bacteria.”

Not only do a lot of yogurts contain probiotics, Zumpano points out, but it’s also a popular food with kids. 

Fermented foods, she adds, are also a good source. These include:

  • Kefir.
  • Sauerkraut.
  • Pickles.
  • Miso.

Apple cider vinegar is a good way to work probiotics into a diet, too. 

Boost immunity with prebiotics

Additionally, you should be sure to get your kids prebiotics. Prebiotics are plant fibers that stimulate the growth of good bacteria. Excellent sources of prebiotics are:

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  • Green bananas or plantains.
  • Jicama root.
  • Yams.
  • Asparagus.

Boost immunity with nuts and seeds

Alpha-linolenic acid (ALA), which is the plant form of omega-3 fatty acids, is shown to fight illness, Zumpano says. Good forms of ALA include:

  • Walnuts.
  • Pumpkin seeds.
  • Hemp seeds.
  • Chia seeds.
  • Ground flaxseeds.

Zumpano also considers nuts and seeds as power foods for the multitude of nutrients they provide. Just to name a few:

  • Protein.
  • Fiber.
  • “Good” fats, like mono- and polyunsaturated fats.
  • Potassium.
  • Magnesium.
  • Zinc.
  • Copper.
  • Manganese.
  • Vitamins E, B6, B12 and A.

Boost immunity with fruits and vegetables

This might sound pretty general, but these are always good standbys. Fruits and veggies provide various antioxidants, which protect cells from damage and disease.

Foods rich in antioxidants include:

  • Berries.
  • Green vegetables such as broccoli.
  • Dark, leafy greens like spinach, kale, collard and mustard greens.

“These power foods pack a punch when it comes to vitamins and nutrients like vitamins A, C, E, B2, B6, K, potassium, folate, magnesium, potassium and zinc,” Zumpano says.

And, of course, vitamin C is key to boosting immunity, and is available in various citrus fruits like oranges, lemons, limes and grapefruit. “Strawberries are great sources for vitamin C, too,” she adds.

Boost immunity with sleep

It’s not just food that can help your kids stay healthy throughout the school year. In fact, Zumpano says that good sleep habits are essential for kids. 

“Good, restful sleep is crucial for kids,” she says. “Sleep is when our bodies rest, regenerate and heal. It’s an essential part of keeping our immune systems functioning as best they can.” 

Boost immunity with exercise

Exercise is also important because physical activity can help keep your body resilient and more likely to fight off infections. “Make sure your kids keep their bodies moving,” Zumpano advises. 

Boost immunity by reducing stress

Another way to help kids be healthy is minimizing stress and anxiety, an admittedly tall task given the ongoing pandemic and the effects it has on kids. From concerns about getting sick to the stress of being separated from friends, it’s a tough time for kids and mindfulness can help

“Deep breathing, meditation and communication can help pinpoint sources of anxiety and stress,” Zumpano says. “Talk to your kids about ways that you can work together to minimize any negative feelings they may be having during these uncertain times.” 

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