Biotics, biotics and more biotics. Where do we start to make all this information a bit more digestible? (excuse the pun..)

The 60 Second Summary

The Gut: A 2,000-Year-Old Secret

Hippocrates, the so-called “Father of Western Medicine,” famously claimed that “all disease begins in the gut.” For centuries, we treated the gut as a simple processing pipe, but modern science has finally caught up to the old Greek. [Useless trivia alert: Hippocrates lived until he was around 90, so he must have been doing something right!] Today, we view the gut as a complex ecosystem—something you feed, balance, and cultivate, much like a garden.

From Discovery to the “Second Brain”

In the 17th century, Antoni van Leeuwenhoek is credited with being the first person to observe microorganisms within the human body. In 1885, Theodor Escherich discovered E. coli, and by the early 1900s, Nobel laureate Ilya Metchnikov was already proposing that fermented milk could prevent “putrefaction” in the intestines and slow ageing. After a relatively quiet period spanning several decades, the gut began to be re-evaluated in the 1990s as an “overlooked organ” or “second brain.”

Since the 2000s, research has entered a new phase, viewing the gut not merely as a digestive organ, but as a complex ecosystem that requires nourishment, balance, and cultivation—much like a garden. During this period, the concept of the “gut–brain axis,” which describes the relationship between the gut and the brain, evolved further into the “gut microbiota–gut–brain axis,” incorporating the important role played by microorganisms.

It is becoming increasingly clear that a healthy gut microbiota may be involved in a wide range of functions, influencing everything from immune function to mental well-being.

What are Probiotics?

The term comes from the word probiosis, meaning “to live together” or “for life”. Probiotics are live microorganisms that, when consumed in sufficient quantities, provide significant health benefits—most notably the improvement of the intestinal environment. 

Where to Find Them

Probiotics are commonly found in fermented foods and dairy products. Integrating these into your daily diet in a balanced way is highly recommended: *

Fermented Foods: Natto, kimchi, sauerkraut, tempeh, miso and nukazuke (rice bran pickles). 

Dairy: Yoghurt and other cultured milks.

* Note: not all fermented foods are considered probiotics, as this depends on the type of microorganisms they contain and whether those microorganisms remain alive when consumed.

What are Prebiotics?

While probiotics are live bacteria themselves, prebiotics are indigestible food components that serve as food for beneficial bacteria in the gut. Oligosaccharides and dietary fibre are among the carbohydrates considered to function as prebiotics. Unlike many other nutrients, these components are not digested or absorbed in the stomach or small intestine, but instead reach the large intestine, where they are fermented by gut bacteria to produce metabolites such as short-chain fatty acids.

Prebiotics are thought to play a role in maintaining the balance of the gut microbiota and supporting overall health.

It has been reported that resistant starch levels in foods such as rice and potatoes increase after cooking and cooling. Resistant starch is a type of carbohydrate that resists digestion and may therefore help provide an additional food source for beneficial gut bacteria.

Where to Find Them

Prebiotics are found in a wide variety of plant-based foods. In general, foods rich in dietary fibre are considered good sources of prebiotics.  

Vegetables: Cabbage, onions, garlic, leeks, burdock root (gobo), and leafy greens.  

Legumes & Starches: Beans, oats, soy products, and potatoes.  

Seaweed & Mushrooms: These are “gut-health heroes” packed with unique fibres that beneficial microbes love.  

Fruits: Many fruits, such as bananas, contain the oligosaccharides needed to feed your gut flora.

What are Synbiotics?

Synbiotics are a strategic approach that involves consuming probiotics (beneficial bacteria) and prebiotics (food for beneficial bacteria) together in order to enhance each other’s effects.

In some cases, the prebiotic components are selected specifically to support the microorganisms being consumed alongside them.

The idea is to help create an environment within the gut in which beneficial bacteria can thrive by effectively providing them with a “packed lunch” of the nutrients they need.

Simple Ways to Practice Synbiotics

Achieving a synbiotic balance doesn’t require a complete lifestyle overhaul. You can start by simply adding one “pairing” to your current meals:

The “Plus-One” Rule: If you’re eating a salad, try adding a yogurt dressing or some fermented pickles.

The Power Dessert: Stir sliced bananas (prebiotic) into yoghurt (probiotic), or drizzle your yoghurt with oligosaccharide syrup.

All-in-One: Fermented vegetables like kimchi or sauerkraut.

What are Postbiotics?

While probiotics refer to “live microorganisms,” postbiotics are preparations containing inactivated microorganisms and their components, along with metabolites produced during fermentation, that may provide health benefits to the host.

In addition to microbial cellular components, postbiotics may also contain metabolites produced during fermentation, such as short-chain fatty acids, peptides, enzymes, and amino acids. Many of these are thought to support digestion, immune function, and the balance of the gut microbiota.

Key Characteristics

Not living microorganisms: Postbiotics consist primarily of inactivated microbial cells, cell fragments, and metabolites produced during fermentation.

Relatively stable: Because they are not living organisms, postbiotics are generally more stable during heating and processing than live probiotics.

Koji Fermentation and Postbiotics

Koji-fermented foods may contain microorganisms that have been inactivated through heating or processing, along with metabolites produced during fermentation.

In this respect, koji-fermented foods may share characteristics with postbiotics.

During the production of foods such as miso, soy sauce and sake, not only koji mould, but also lactic acid bacteria and yeast, play important roles in fermentation. This process produces a variety of metabolites, including amino acids, lactic acid, and alcohol. When products such as miso, soy sauce, and sake undergo heat treatment or processing, many of these microorganisms may become inactivated, whilst numerous beneficial compounds remain.

In this way, koji-fermented foods share certain characteristics with postbiotics, serving as valuable sources of inactivated microorganisms and fermentation-derived compounds, whilst also providing the flavour, digestibility, and umami associated with traditional fermentation.

Where to Find Them

Koji Products & Condiments: Heat-treated soy sauce, miso, sake and commercially pasteurised amazake.

Dairy & Fermented Beverages: Pasteurised yoghurt and heat-treated lactic acid bacteria drinks.

Supplements: Products containing heat-killed lactic acid bacteria or yeast.