Gut Health, Immune System and Nutrition | Activia

Gut Health, Immune System, and Nutrition

Research shows that the gut health plays an even bigger, more complex role in our overall health than we previously assumed. An effective and functional immune system is an important characteristic of gut health[1].

The gut: a major line of defense for the body

Our gut is like a gatekeeper, controlling the flux of bacteria. It offers 3 levels of defenses:

1. Gut microbiota

The gut microbiota is the population of microorganisms residing in the intestine. It prevents the overgrowth of potentially harmful bacteria by competing for space and food. It feeds on certain food components and produces short-chain fatty acids which play a role in immune response[2].

2. Gut barrier

The intestine is lined with epithelial cells covered with mucus. These cells provide a physical and biochemical barrier with tight junctions, preventing harmful microorganisms and toxic substances from entering while allowing beneficial nutrients to pass through.

3. Immune system

70% of the entire immune system is located in the gut[3]. The interactions between the immune system and the gut microbiota have a vital role in maintaining the body’s defense. The immune system cells recognize, identify and neutralize any harmful substances that have found their way into the body.

Nutrition for the immune system

Several factors can influence our immune system, such as age, genetics, physical activity, diet, and sleeping habits.

Good nutrition is important for the immune and gut microbiota health.  A healthy, balanced diet and lifestyle can support our immune system, whereas a poor diet can compromise the immune system, leading to greater susceptibility to infections[4]. As such, a diverse healthy diet is one of the steps we can take for a healthy immune system.

In addition, there are specific nutrients which are essential for the proper functioning of the immune system.  For instance, vitamin A and zinc are nutrients that contribute to the normal function of the immune system. Several other vitamins and minerals are also involved in immune response[5].

It is important to note that there is no evidence that more of a nutrient, beyond our needs, will lead to a stronger immune system. There is no such thing as “boosting the immune function”. In fact, you don’t want your immune function to be above normal or overreactive.

The idea is to eat a variety of foods and a have healthy, balanced diet and lifestyle. The more diverse the diet, the more diverse the microbiota.

Some foods and components can also be of particular interest, helping to nourish and strengthen the gut microbiota, as well as protecting the gut barrier.

  • Fermented foods with live cultures, such as yogurt and kefir, help increase the diversity of the gut microbiota

  • Fermented foods that contain certain probiotics, such as probiotic yogurt, contribute to a healthy gut microbiota

  • Prebiotics, which are a type of dietary fibre found in certain vegetables and fruit, help feed and stimulate the growth of beneficial bacteria in the gut and enhance the gut barrier sealing

In summary, a rich diverse diet with a variety of foods, including certain probiotic-containing foods, are important in helping us meet our nutrient needs and support the proper function of the immune system and gut microbiota.

Read the article on CDHF’s website: How Nutrition Can Support Gut Health and the Immune System


[1] Bischoff SC.‘Gut health’: a new objective in medicine? BMC Med 2011;9:24.

[2] Koh A et al.From dietary fiber to host physiology: short-chain fatty acids as key bacterial metabolites.

Cell 2016;2;165(6):1332-1345.

[3] Vighi G et al.Allergy and the gastrointestinal system. Clin Exp Immunol 2008;153(Suppl 1):3-6.

[4] Gut Microbiota for Health. 2020.Why good nutrition helps feed your immune system.

[5] Gombart AF et al.A review of micronutrients and the immune system–working in harmony to reduce the risk of infection. Nutrients 2020;12(1):236.

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