What are posbiotics and how do they boost the immune system?

Postbiotics are substances or organisms secreted by live bacteria during the fermentation process of non-digestible fibers that feed certain microorganisms in our gut. These “waste products” can affect gut acidity, inhibit the proliferation of pathogens, and improve health.

Short-chain fatty acids, peptides, enzymes, and proteins are examples of substances produced or released by beneficial bacteria (1).

Postbiotic is a new term. But scientists and gut experts have been familiar with the benefit they provided for health for years. So, why are posbiotics a hot topic in nutrition now?

Postbiotics can boost and support the immune system while also fighting the antibiotic effects on gut health. They interact with our immune system in different ways. Recent studies suggest that they can keep the balance for a healthy gut, influence the gut barrier function that prevents the invasion of harmful microorganisms and substances, improve the antibody response, and support the messaging process between the gut microbes and the immune system (2).

In addition to that, postbiotics fit as an alternative to probiotics. Because they are not alive, they are easy to transport and store. They have a longer shelf life, and their intake risks are low, especially for immunocompromised people (3).

Understanding the gut microbiome

Our gut flora is home to an uncountable number of bacteria (10-fold more than the total number of our cells) and a variety of other microorganisms. They not only live there, but they take care of the house. We know this because germ-free animals require more energy to live, have lesser antibody production, and lack other structures that interact with the immune system to protect them (4).

The population that colonizes our microbiota stabilizes during the first few years of life. The first year is considered the most relevant for microbiota development and the foundation for our health. By the age of seven, there will be little to no modification (5).

That is why birth methods matter to our health. Children born by cesarean will get their first bacteria from other people (the doctor or nurse) and the hospital environment. Natural birth puts the child in contact with the protective vaginal flora of their moms before anything else. It impacts the diversity and type of bacteria that will colonize a baby’s gut.

Breast milk also plays a role in stabilizing the gut microbiota during childhood. There is evidence that breastfed babies have more lactobacillus and bifidobacteria species in their guts. Breast milk is a source of antibodies from mom and non-digestible prebiotic oligosaccharides that beneficial bacteria will ferment (6).

The food that children eat more often and the intake of antibiotics at an early age play an even relevant role in shaping the intestinal microbiome that will compound our gut as adults.

We can classify the bacteria in our gut into four categories: beneficial, commensal (neither good nor bad, and they make up most of the population), bad, and very bad. If the equilibrium is disturbed, the ecosystem can contribute to many intestinal diseases. Prebiotics, probiotics, and postbiotics are essential to keep a healthy balanced microbiome.

What is the difference between prebiotics, probiotics, and postbiotics

Making it simple, here is an analogy: prebiotics are the raw material that workers (probiotics) will use to produce finished goods (postbiotics). Once probiotics make their way to the gut, they start processing prebiotics and converting them into postbiotics. The three of them offer health benefits, but they differ in nature and role.

Prebiotics are carbohydrates or non-digestible fibers present in fruits, vegetables, and grains that feed the beneficial bacteria that already live in the gut and the probiotic ones. Raspberries, artichokes, green peas, broccoli, chickpeas, lentils, and beans are some examples. Mucilaginous foods (source of soluble fiber) such as figs, chia and flax seeds, okra, aloe vera also act as prebiotic.

Probiotics are live microorganisms. The most used are bacteria of the family Lactobacillaceae, Bifidobacteriaceae, and Streptococcaceae. Saccharomyces boulardii, a yeast, is another popular probiotic. They do not colonize the gut bacteria permanently. They are guests. And the kind of guest you want in your house, at least under normal circumstances. Some of them stay longer while others are just passing through.

Probiotics provide all sorts of benefits for overall health. They are known for improving digestion, bowel movements, liver health, and skin. They influence the mucosal barrier, reduce the impact of stress in the gut and immune system (7).

There is one problem, though. Probiotics might negatively impact the health of immunocompromised people and anyone undergoing cancer. Infants, especially premature ones, should avoid probiotics because their immune systems are still developing. And that is when postbiotics are a game changer.

Postbiotics, as discussed above, are byproducts or "waste products" of beneficial bacteria. They are safer for general use because they are not alive. Furthermore, they offer many health benefits, including the regulation of digestion, absorption of nutrients, detoxification, support to the immune system, and gut-brain communication.

Postbiotics sources and how to boost them naturally

Our microbiota is relatively stable during adulthood following the population settled when we were kids. But diet and lifestyle are essential in modulating the gut microbiome.

Postbiotics can be produced and extracted in laboratories. For therapeutic purposes, a pill can be convenient.

You might have consumed natural sources of postbiotics already if you are familiar with fermented foods and beverages such as kefir, kombucha, yogurt, kimchi, sauerkraut, tempeh, miso.

Fermented foods are known for being sources of probiotics. If not processed, they are both sources of live microorganisms that produce the postbiotics (probiotics) and postbiotics - they contain many short-chain fatty acids.

The best way to increase postbiotics in our gut is by eating a balanced and healthy diet rich in prebiotic and probiotic foods whenever possible.

Apple cider vinegar, for example, can easily be added to a salad. It is a source of acetate, one of the most common short-chain fatty acids in the body. Increasing the presence of acetate in the gut helps maintain a healthy gut barrier and reduce inflammation in the body.

Another fatty acid that boosts immunity is butyrate present in resistant starches such as potatoes, rice, oats, and beans (8).

A variety of vegetables, fruits, grains (especially whole grains), and fermented foods, in general, can help balance the microbiome in our gut and improve our immunity.

*Image by Edwina_mc from Pixabay