Back to School, Back to Germs (This Is Actually Good For Your Child)

Ah, back-to-school season…time for sharing crayons, high-fiving new friends, and, yep–runny noses. As parents, we often heave a deep sigh when it comes to all the grubby, grim-y germs our kids are exposed to at school (and bring home from school!). Hold on to that sigh, though, because research has shown that exposure to germs plays a vital role in a healthy gut microbiome which, in turn, leads to a stronger immune system. So instead of merely tolerating back-to-school germs, let's celebrate them knowing that they can actually benefit your child's health.

The gut microbiome and immunity

Before we dive into how germs boost your child's health, let's understand what the gut microbiome is. The gut microbiome consists of trillions of microorganisms residing in the gastrointestinal tract, including bacteria, viruses, fungi, and other microscopic critters. Collectively, they are known as gut microbiota, a complex ecosystem that plays a fundamental role in your child’s overall health, including digestion, nutrient absorption, and even the regulation of mood and mental health.

More importantly, the gut microbiome is deeply intertwined with the immune system. Approximately 70% of the body's immune cells are found in the gut, making it a crucial hub for immune activity. The gut microbiome helps educate the immune system by exposing it to various foreign substances, including germs, which ultimately helps it learn and differentiate between harmful pathogens and harmless antigens.

Now, you might be wondering, "Aren't germs gross/bad/harmful?” While it's true that some germs can cause infections and diseases, not all germs are bad. In fact, exposure to certain germs can benefit your child's health, particularly when it comes to their immune system and gut health.

Exposure to germs and immunity

Your child will encounter a diversity of microorganisms at school which is actually a critical aspect of building a robust immune system. During the early stages of life, a child's immune system is still developing and learning to recognize different pathogens. When children come into contact with germs, their immune system gets an opportunity to practice and strengthen its defenses.

In particular, germs stimulate the production of antibodies. Antibodies are specialized proteins that recognize and neutralize harmful invaders like bacteria and viruses. When children encounter various germs, their bodies start producing specific antibodies tailored to fight those germs. This process, known as adaptive immunity, enables the immune system to mount a faster and more effective response if the same germs invade the body in the future.

The concept of "hygiene hypothesis" supports the idea that early exposure to germs and infections can protect against allergies and autoimmune disorders. Researchers have observed that children who grow up in cleaner and more sanitized environments are more susceptible to allergies and autoimmune conditions than those who are exposed to a wider range of germs.

It's all about diversity

The gut microbiome thrives on diversity, much like a symphony that requires a variety of instruments to create harmonious music. Exposure to various germs is like adding new instruments to this symphonic ensemble, enhancing the diversity of gut microbiota. Each type of microorganism in the gut plays a specific role in digestion, nutrient absorption, and even influencing the gut-brain axis, which is the bidirectional communication between the gut and the brain.

Of course, classrooms, playgrounds, and school cafeterias are hotspots for germ diversity. Here are some of the germs your child might encounter and how they contribute to gut health and immunity:


Bacteria such as Lactobacillus and Bifidobacterium are commonly found in fermented foods like yogurt and play a vital role in maintaining gut health. They aid in digesting lactose, enhancing nutrient absorption, and crowding out harmful bacteria.


While not all viruses are harmful, some can be beneficial. For instance, bacteriophages, viruses that infect bacteria, help control the balance of gut bacteria, ensuring a healthy ecosystem.


Fungi like Saccharomyces boulardii are known for their gut-protective effects. They help reduce inflammation and maintain a robust gut barrier, preventing harmful substances from entering the bloodstream.


Some parasites, when present in controlled amounts, can stimulate the immune system and contribute to a well-balanced gut microbiome.

Healthy germ exposure

While exposure to these bacteria, viruses, fungi, and parasites can be beneficial, it's important to strike a balance between promoting healthy germ exposure and preventing the spread of harmful infections. Here are some tips to encourage healthy germ exposure for your child:

Regular handwashing

Teach your child the importance of washing their hands regularly, especially before meals and after using the restroom. Proper handwashing is one of the most effective ways to prevent the spread of harmful germs.

Balanced diet

A healthy and balanced diet supports a strong immune system and a diverse gut microbiome. Encourage your child to eat a variety of fruits, vegetables, whole grains, and lean proteins. Including probiotic-rich foods like yogurt, kefir, sauerkraut, and kimchi in your child's diet can introduce beneficial bacteria into their gut, further supporting their gut health.

Play outside

They don’t call it the great outdoors for nothing. Encourage your child to play outdoors. Nature exposes them to a broader range of germs and microorganisms, contributing to a more diverse gut microbiome.

So there you have it: the A, B, C’s of back-to-school germs. Remember, your kids aren’t just learning long division–their bodies are also growing a more diverse microbiome and learning how to make antibodies for a stronger immune system. Here’s to a healthy school year!

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