How Vitamin D and Probiotics Support Your Child's Immunity

and why you need this more than ever

Kelly Sikkema/

Trust your gut! Understanding the microbiome is key to maintaining everything from digestive health to proper immune system functioning. And with all that's happening in our world lately, it's no surprise the spotlight has also been on how the "sunshine" vitamin could help brighten the outlook. But if you think you know everything you need to about Vitamin D, think again! Beyond its role as an essential vitamin for maintaining bone health, ongoing studies and research highlight the importance of both Vitamin D and probiotics in supporting optimal health and immunity. 

As we head into what is arguably the most nerve-racking cold and flu season in living memory, it is more important than ever to ensure children receive adequate amounts of both Vitamin D and probiotics. Studies have suggested that COVID-19 patients who are Vitamin D deficient are at increased risk from complications and hospitalization. Although there isn't enough evidence to conclude whether that is a fact, let's take a closer look at what we know about how probiotics and Vitamin D work in tandem to support your immune system, and why you should equip yourself with the right supplements this winter.

The Mighty Microbiome 

Though its name may contain "micro," there is nothing small about the impact the microbiome has on your child's health and immunity. The microbiome consists of trillions of microorganisms known as microbiota, which includes bacteria, fungi, and viruses that are either beneficial (symbiotic) or disease-promoting (pathogenic).1 Each person's microbiome is unique and affected by factors such as genes, environment and diet. Pathogenic and symbiotic microbes can coexist in a healthy body, essentially forming an immune system-and-microbiota alliance.

However, when the balance is disturbed by an illness, the use of antibiotics, or an unhealthy diet, the pathogenic microbes will cause the body to be more susceptible to disease and infections. As such, the immune system has evolved mainly to protect and maintain the symbiotic relationship with our microbiota.2 The microbiome affects tissue such as the nervous and immune systems by chemical messaging. Understanding the role the microbiome plays has been nothing short of revolutionary in understanding the immune system's complexity (see what we mean about how mighty your microbiome is?). The microbiome has even been called a supporting organ because of the critical roles it plays in immune system function and maintenance of the human body. 

The "Pros" of Probiotics

In the cosmic battle within the universe of your microbiome, probiotics are the good guys. As the name suggests - pro-biota, meaning "for life" - probiotics are squarely in the camp of microbes that are on your side. Probiotics are made up of live microorganisms such as good bacteria that help your body ward off harmful bacteria that can make you ill. Different strains of probiotics confer various benefits and have been used to help treat digestive issues, urinary tract infections, inflammatory bowel syndrome, Crohn's disease and eczema in children. These gut-dwellers help keep those pathogens in check by restoring bacteria to a positive balance that contributes to healthy immune function. Common probiotic strains include Lactobacillus reuteri ProtectisLactobacillus rhamnosus GG and Bifidobacterium animalis ssp. lactis BB-12.

The Lesser Known Facts About Vitamin D

Let's start this off with a neat fact: "Vitamin" D is actually a hormone in its active form. It is mostly produced in the skin in response to sunlight and dietary sources (estimated 10-20%).3 The kidneys then convert it into an active hormone called Calcitriol.4 Calcitriol helps to increase the amount of calcium the gut absorbs, and prevents calcium loss from kidneys. For growing children, Vitamin D deficiency may result in a condition called rickets. Deficiency in Vitamin D has also been linked to increased inflammation and chronic diseases such as asthma, suggesting it plays a significant role in auto-immunity and immune-modulation.5

Immuno-Modulating Heroes

One of the most beneficial effects of both probiotics and Vitamin D is the modulation of the immune system, by enhancing innate immunity and modulating pathogen-induced inflammation caused by adaptive immunity.6 Innate immunity is the first line of defence against infection, and is initiated following exposure to foreign substances or tissue injury. When the innate immune response is insufficient, adaptive immunity is activated to attack the specific pathogen that is present. This system can also learn about the pathogen and develop immunological memory, thus becoming responsible for autoimmune reactions.

The microbiota calibrate all aspects of the immune system, while Vitamin D controls innate and adaptive immunity in the gut. In other words, they regulate the immune system by supporting the innate response, and modify the adaptive system to respond appropriately and proportionately in order to avoid dangerous complications such as a cytokine storm, where the body attacks its own cells and tissues in the process. Vitamin D can inhibit pro-inflammatory cytokine production, leading to ARDS (Acute Respiratory Distress Syndrome) caused by the severe form of COVID-19.7

So in this scenario, which is the hero, and which is the sidekick? The truth is that Vitamin D and probiotics work together synergistically to increase your immune defences and may help reduce severe complications from disease and infection.

Take a Holistic Approach to Disease Prevention

Preparation and healthy habits are essential. You can take a holistic approach to disease prevention and health by implementing the following tips to strengthen your child's immune system ahead of cold and flu season.

Eat a Nutritionally Balanced Diet

You've probably heard the adage, "You are what you eat." Diet is an important factor in maintaining healthy gut flora. Eat a variety of whole foods, including vegetables, legumes, and fresh fruits. They are high in fibre, which stimulates the growth of good bacteria. Incorporate probiotics into your diet with L.reuteri protectis, a natural lactobacillus, to restore a healthy balance in the digestive system. Cut out the processed foods and sugars which can cause inflammation and reduce white cells that help fight infection.

Stay Active and Sleep Well

It's a no-brainer: sleep more, stress less and get a move on! Regular exercise can help your immune system fight infection, boost your endorphin levels, help with stress by lowering cortisol (stress hormone) levels and help you sleep better. These will all help with getting your body into an optimal state to fight off those colds. Bonus: safe sunlight exposure will also help boost Vitamin D production.

The Importance of Supplements

The body can synthesize Vitamin D from exposure to sunlight, but getting enough sunlight can be a challenge in the winter months, and many people can become deficient. Unfortunately, dietary intake alone will not be sufficient. Therefore, it is essential to supplement with at least 400 IUs of Vitamin D for children under 12 months, and 600 IUs a day for kids over the age of 1, to ensure adequate Vitamin D levels.

When it comes to probiotics, there are myriad reasons your child's microbiota could be off-balance. While you can get them from food sources such as yogurt or fermented foods, ensuring they are getting the right amounts can be tricky. Adding a probiotic supplement will help ensure your children are getting the daily dose they need. 

"Probiotics can be most effective at both ends of the age spectrum because that's when your microbes aren't as robust as they normally are,” writes Dr. Allan Walker of the Harvard Medical School. “You can influence this huge bacterial colonization process more effectively with probiotics during these periods."1

Choosing the Right Probiotic 

The verdict is in: probiotics are essential for your children's health and immune functioning. To bring you this article, we've partnered with BioGaia, an innovative Swedish healthcare company and world leader in probiotic products and supplements for over 30 years. BioGaia's clinically-proven products contain Lactobacillus reuteri, a probiotic bacteria that helps good microorganisms restore a natural balance in the gut. L. reuteri is one of few bacteria that has co-evolved with humans, and as such it naturally colonizes and has a strong adaptation. As of January 2020 L. reuteri has been tested in 217 clinical trials and has proven both effective and safe in children and adults.8

We especially recommend their Junior Tablets with Vitamin D, which packs all the benefits of probiotics and Vitamin D outlined above with 100 million live active Lactobacillus reuteri Protectis and 800 IUs of Vitamin D3s. Now there's a powerhouse duo if we've ever seen one, made especially for your children!

Note: Always consult with a healthcare professional before starting any course of supplements.


1 The Microbiome, Harvard School of Public Health

2 Role of the Microbiota in Immunity and inflammation

3 You and Your Hormones, the Society for Endocrinology

4 You and Your Hormones, the Society for Endocrinology

5 Vitamin D: Nutrient, Hormone, and Immunomodulator Probiotics and immune health

7 Vitamin D Status in Hospitalized Patients with SARS-CoV-2 Infection What is L. reuteri?