Supporting your Child’s Immune System for Back to School

Written by: Nesrine Cheikh, RD, DDePT, MScFN, CDE

Updated: March 24th, 2026

It’s that time of year again….back-to-school! You may be excited to be sending your child back to school after a long summer, or you may be nervous, wondering how your child will handle a new classroom setting.  

Regardless of your feelings, you are likely very busy preparing for the back-to-school season by packing backpacks, buying school supplies and new clothes, figuring out lunches, and organizing fall schedules. You may be wondering how you can prepare your child so they will be as healthy as possible when they head back to class. You may also begin to feel anxiety as you contemplate the many illnesses your child will be exposed to and develop throughout the upcoming school year – after all, a sick child can be overwhelming for the whole family!  

Fortunately, there are some things you can do as a parent to support your child’s immune system. Read on to learn what you can do to help your child have the healthiest school year possible.   

More of a visual learner? Download our ‘Supporting your Child’s Immune System for Back to School’ infographic!

Follow a Healthy Diet 

What your children eat can greatly impact their immune system and children need to have a varied and nutritionally balanced diet. Not only can nutrients from the diet help improve the immune system’s functionality, but they can also reduce illness severity. Here are some ideas of what your child can eat to support their immune system: 

Focus on vegetables and fruits: 

Fruits and vegetables contain vitamins and antioxidants that support the immune system to prevent and fight off infections. 
Try to eat at least 1 serving of vegetables or fruits at each meal and snack, for a total of 5 servings per day, on average. A serving of vegetables or fruits = 1 cup raw , ½ cup cooked, or 1 medium piece of fruit

Aim for balanced meals and snacks:  

Provide meals and snacks that contain a vegetable or fruit, a protein source like: meat, tofu, or legumes, and whole grains like brown rice or whole wheat pasta.  
Each type of food should make up 1/3 of a child’s plate.

Encourage variety:  

The more colour the better! The nutrients in different colours of vegetables and fruits will support your child’s immune system in different ways. Some colourful examples include: berries, carrots, sweet potatoes, dark leafy greens, broccoli, asparagus, beets, avocados and squash.

Don’t feel pressured if your child doesn’t follow these recommendations right away. It’s ok to start slowly, beginning with foods and textures you know your child enjoys and gradually adding new foods over time.  

Try adding new foods into your child’s diet, such as: 

Adding to smoothies 
Blending into sauces and soups 
Adding to baked goods

It may be helpful to work alongside a dietitian when introducing your child to new vegetables and fruits. 

If your child refuses to eat their vegetables, don’t despair! From a nutrition standpoint, fruits and vegetables are nearly identical. If your child prefers eating fruit, they may still be meeting their nutrient needs through their diet. However, it is still important to encourage your child to eat as wide a variety of foods as possible to reduce the chance that your child will develop picky-eating behaviours as they grow up.   

Supplements may benefit children who are missing food groups or key nutrients in their diet. Always speak with a dietitian first before trialling supplements.  

Focus on key vitamins and nutrients 

Children can get most of what they need from eating a healthy, balanced diet. However, while certain vitamins and nutrients play a big role in immune system functioning, it can be difficult for a child to meet their requirements for these nutrients through diet alone. As such, special consideration should be given to particular nutrients.   

Vitamin D 

Vitamin D is one of the most common vitamin deficiencies among both children and adults. Our skin can make vitamin D when exposed to sunlight, but there many things that can limit how much vitamin D we get this way.  

For example, the sunscreen our children wear for protection from burns and skin cancer also blocks the UVB rays needed for their skin to make vitamin D.  It can also be difficult to get enough vitamin D through the diet, since it occurs naturally in very few foods.  

This vitamin plays a very important role in the immune system – it is involved in regulating certain genes involved in immunity against viruses and bacteria. Clinical studies show that vitamin D deficiency can lead to higher rates of infection^1,2; autoimmune diseases³, and allergies⁴.  

You can provide your child with foods that contain vitamin D, such as fatty fish, egg yolks, and mushrooms. You can also offer foods fortified with vitamin D, such as cows’ milk, yogurt, and cereals. However, since it is difficult to get enough vitamin D through natural means, supplementation is recommended:  

Infants who are 12 months or younger →  400 IU/day 
Toddlers and adolescents → 600 IU/day

Omega-3 

Omega-3s are essential fatty acids that can play a crucial role in supporting immunity. For example, both Docosahexaenoic acid (DHA) and Eicosapentaenoic acid (EPA) are types of omega-3 fatty acids that support an individual’s ability to fight off infection by reducing the body’s inflammatory response to illness⁵. 

It can be a challenge to get enough omega-3s through the diet alone. The best dietary sources of omega-3s are fatty fish such as salmon, while smaller amounts can also be obtained from plant oils in nuts and seeds, such as walnuts and flaxseeds.  

Further, some foods are fortified with omega-3s, such as certain brands of eggs, yogurt, milk, and soy beverages⁶. Supplementation, which can begin as early as birth, is an excellent way to help your child meet their omega-3 requirements. The recommended supplement dosing for omega-3 fatty acids ranges between 500 mg to 1600 mg per day, depending on your child’s age and needs.   Fun fact: Both vitamin D and omega-3 are fat soluble and are often combined into one supplement! This 2-for-1 combo can make it easier to give both essential nutrients to your child every day. 

Vitamin C and Zinc 

Vitamin C and zinc deficiencies both significantly impact mental and physical development in children and can result in impaired immune function⁷. Fortunately, both vitamins are readily available in many common foods. For example, zinc is found in: 

Meat 
Fish 
Seafood 
Eggs 
Dairy products

Vitamin C can be found in fruits and vegetables such as: 

Kiwi 
Oranges 
Broccoli 
Cauliflower  
Peppers 
Strawberries 
Tomatoes

Although food should be the primary source of these vitamins, your child may benefit from supplementation if you believe they aren’t meeting their zinc or vitamin C requirements through diet alone. Depending on your child’s age and needs, the recommended doses are 5-10 mg of zinc and 15-75 mg of vitamin C per day.  

Iron 

Iron deficiency is also common among children and may lead to decreased immune function. Deficiency of this mineral has been linked to lower levels of certain types of white blood cells and affects children’s ability to fight off infections.⁸  

Iron is found naturally in many foods such as: 

Meats 
Poultry 
Eggs 
Leafy greens 
Beans 
Lentils

However, if your child drinks a lot of milk or eats a lot of dairy products, they may not absorb as much iron from their food. When high amounts of calcium interact with iron in the digestive tract, it can lead to reduced iron absorption. Your child may also have lower iron levels if they don’t eat adequate amounts of iron rich or iron fortified foods, or if they are genetically susceptible to deficiency. If you are concerned if your child is meeting their iron needs, discuss testing with your pediatrician.  

Iron supplementation is not recommended unless you know your child has a deficiency. However, it’s important to recognize the role this mineral plays in supporting immunity and take steps to ensure your child is meeting their daily iron requirements. 

Although your child may need help to meet their daily requirements for these vitamins and nutrients, be sure to talk to a dietitian before beginning supplementation. Too much of some nutrients can be as harmful to your child’s health as not enough!  

Probiotics 

Probiotics are “good bacteria” that improve certain aspects of our health when taken in adequate amounts.  There are many different types, or strains, of probiotics. Each strain is unique and can help manage specific health conditions, such as antibiotic-associated diarrhea (such as Lactobacillus rhamnosus and Saccharomyces boulardii)⁹, childhood eczema (such as Roseomonas mucosa)¹⁰, and colic (such as Lactobacillius reuteri¹¹, Bifidobacterium longum¹² and Pediococcus pentosaceus¹²).

For example, Lactobacillius Rhamnoses G.G (LGG) has been shown to have multiple benefits for overall health, including improving the gut barrier¹³, preventing unhealthy bacteria from infiltrating the gut¹⁴, and regulating immune response¹⁵. These good bacteria can bind to intestinal immune cells to help fight off harmful bacteria and viruses.  

You can consume probiotics in foods such as some yogurt and kefirs, as well as in supplement (pill or powder) form.  

Other healthy lifestyle tips:  

Along with making sure your child is getting the right nutrients through the diet, there are other things you can do to help them stay healthy during the school year.  

 Hygiene 

Teaching children good hygiene habits goes a long way to keeping germs from spreading through the classroom. For example, hand washing is the best way to defend against the spread of many illnesses, from colds to stomach bugs. Show your child how to wash their hands properly, and encourage frequent hand washing before and after eating, after using the toilet, as well as after messy activities. Coughing or sneezing into an elbow, as well as masking when feeling unwell, are ways your child can help prevent germs from spreading to other students. Finally, encourage your child to stay away from sick people as much as possible.  

Physical Activity 

Keeping active is an excellent way for both children and adults to support their immune system. Not only can physical activity help the immune system defend the body against germs, but it can also decrease the length and severity of symptoms of an illness¹⁶. Children do not have to be involved in sports to experience the immunity supporting benefits of physical activity – any activity your child enjoys that gets their body moving can help, such as dancing, swimming, biking, and even playing at the playground.  

Rest 

Another important way to help keep your child healthy is to ensure they are well rested. Research shows that immune system function is strongly linked to sleep. When children and adults get too little sleep, they become more susceptible to getting sick after being exposed to viruses or bacteria, such as the common cold virus¹⁷. Depending on your child’s age, it is recommended that they get anywhere from 8-14 hours of sleep in a 24-hour period (if you have young children, this amount includes naps)¹⁸. 

Hydration 

Adequate hydration can support many aspects of a child’s health. It can improve blood circulation and organ functionality and can maintain healthy bone and teeth. It’s also involved in keeping mucosal membranes hydrated to defend the body from pathogens.  Water intake ranges anywhere from 4oz (infants and toddlers) up to 8 cups as they hit their teens. 

Vaccinations 

Don’t forget to stay on top of recommended vaccines to prevent or reduce the severity of specific viruses and illnesses! 

Normalize getting sick 

Keep in mind that although frustrating, it is normal for young children to get sick often throughout the year. Young preschool- or toddler-aged children can get sick with respiratory illnesses and stomach bugs about 8-10 times in a year¹⁹ – sometimes even twice in one month!  

Children are exposed to a wide variety of viruses and bacteria every day, at daycare, schools, public spaces, and family visits. There are nearly 200 different cold viruses alone, and these viruses constantly mutate to slip past our immune system’s’ defenses. No matter how careful you are, avoiding all germs to prevent your child from getting sick is virtually impossible. Nor should you want to – exposure to bacteria and viruses help a child develop a strong immune system. 

Final Thoughts 

Is getting sick completely preventable? Nope! Following a healthy diet and lifestyle can provide huge benefits to immune support, but remember, we are all human and getting sick is a normal part of life. If you ever have any concerns about your child’s immunity or nutrition, please reach out to your pediatrician and pediatric dietitian for more information on how to better support your child’s health.  

Download the Back to School Infographic!

References 

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