Prebiotics, probiotics and postbiotics, oh my!

These terms are all the buzz in the health sphere, and for good reason! Our gut does some amazing things as you’ve learned in the past month from my other blog posts. If you haven’t checked them out, see the links at the bottom for more gut health reading! For optimal gut health, we need to be feeding our microbiome with the right things (prebiotics) and helping to colonize a good population of microbiota (probiotics) so that they can create nutrients, proteins and beneficial compounds for the rest of our body to use (postbiotics). Let’s dive in and learn more about prebiotics, probiotics and postbiotics now!

What is a prebiotic?  

Prebiotic fiber rich foods are those that feed the good gut bacteria which break them down and create many beneficial by-products, known as postbiotics (more on these to come). 

Prebiotic fibers that occur naturally in foods include:

• Fructans, including inulin and fructooligosaccharide.
• Galactooligosaccharides and trans-galactooligosaccharides.
• Resistant starches and oligosaccharides.
• Polyphenols and cocoa-derived flavanols.

Common prebiotic foods include:

• Asparagus
• Bananas (greener)
• Barley
• Beans
• Sugar beets
• Chicory
• Garlic
• Honey
• Human and cow’s milk
• Onions
• Peas
• Rye
• Seaweeds and microalgae
• Soybeans
• Sunroot
• Tomatoes
• Whole grain wheat

Probiotics are more familiar to many than prebiotics but what exactly are they?

Probiotics are non-pathogenic micro-organisms that, when ingested or applied, exert a positive influence on host health. In order to benefit the gut microbiome they must be able to withstand stomach acid and bile and make it to the intestines where they will colonize, often temporarily. 

Studies have looked at the use of probiotics and have shown that probiotics have many effects on human health, including:

• Regulating local and systemic immune function
• Preventing systemic and GI related infections
• Regulating inflammation (both in the GI tract and throughout the body)
• Helping to regulate appetite via the leptin and ghrelin pathways (our hunger and satiety cues)
• Providing nutrients to metabolic pathways that control things like glucose, cholesterol and amino acids  (protein)  
• Supporting intestinal mucosal barrier (gut lining) function
• Preventing neoplastic/cancerous changes
• Regulating bowel motility 

Common probiotic supplements include Lactobacillus, Bifidobacterium, Streptococcus and Saccharomyces Boulardii. Within many of these species, there are different strains of probiotics which can exert different effects. There are many things to look for in a probiotic supplement including quality, shelf stability, ability to survive in the upper GI tract, and potency. 

You can also get probiotics from food by incorporating things such as yogurt, kefir, sauerkraut, kimchi, miso, and kombucha into the diet. It is important to note that dietary changes and fecal transplant are the only things to permanently change the gut microbiome. Probiotic supplements are more like temporary placeholders, while working on changing the diet to promote microbiome health and diversity. Probiotic supplements can help to crowd out pathogenic bacteria while the diet is changed in a way to support a healthier gut microbiome. As I’ve noted in the past, a diverse diet = a diverse and happy gut microbiome! 

And now, what exactly is a postbiotic?

Most people by now have heard of prebiotics and probiotics but postbiotics is a newer term in the mainstream literature for something that has been occurring all along. Postbiotics are the downstream metabolic end products of what our gut microbiota are creating by digesting prebiotics and other foods. Postbiotics include things like vitamins and nutrients such as Vitamin B and Vitamin K, amino acids (proteins), and antimicrobial peptides which protect against the growth of pathogenic bacteria. Another postbiotic product are the short chain fatty acids which include butyrate, acetate and propionate. These are produced during the fermentation of prebiotic fibers. These short chain fatty acids are an energy source for the intestinal lining, liver and muscle cells. They also help to modulate immune responses in the gut. Butryate has been implicated in brain health and cardiometabolic health. 

As you can see, there is a lot going on in our gut that we are not even aware of. This underlines the importance of supporting the gut microbiome with a healthy and diverse diet to create optimal health and ensuring we are getting prebiotics, probiotics and postbiotics necessary for a healthy gut and a healthy life.