Introduction

Probiotics are microorganisms—live bacteria—that, when consumed in sufficient amounts, help to improve the balance of gut flora. In other words, they have beneficial effects on health.
You can find them in all fermented foods such as yoghurt, kefir, fermented vegetables, miso, or sauerkraut.

Prebiotics are fermented ingredients that are not digested and, when they reach the intestine, they develop and have a beneficial effect. That is, they do not contain live organisms, but they do promote the growth and wellbeing of the bacteria already present in our gut, helping them to reproduce. As a result, a healthy intestinal flora is achieved. Hence, the effect of prebiotics is clearly long-term.

The most representative prebiotics are inulin and fructooligosaccharides (FOS), and they can be found in almost all fruits and vegetables, especially those rich in lignin, which is a type of insoluble fibre. Artichokes, onions, garlic, asparagus, leeks, bananas, legumes, sweet potatoes, potatoes… as you can see, these are foods that are usually part of our daily diet.

What do these elements provide us with?

Bear in mind that the gut is a barrier to the entry of external substances. We typically carry around a kilo of intestinal bacteria, most of which, if our diet is appropriate, coexist with us in symbiosis. They colonise the intestine and prevent less desirable bacteria from settling there.
A healthy gut flora helps to improve digestion and reduce gas-related discomfort.
It acts as a protective barrier against toxins, harmful microorganisms, and pathogens—essentially an intestinal filter.
It also improves nutrient absorption.
It prevents aggressive or harmful substances from entering the bloodstream, resulting in fewer allergies.
It helps improve conditions such as Crohn’s disease and colitis.

Ways to modify this bacterial flora:

– **Environment**: Babies born via caesarean section have a different microbiota. The simple act of passing through the birth canal means they ingest part of the mucosa, which contains beneficial microorganisms that can help colonise the gut.
– **Diet**: Depending on our diet, different colonies of bacteria will thrive in the gut. People who consume a lot of fermentable starches and sugars are more likely to encourage the growth of less desirable bacteria like Clostridium. On the other hand, a diet richer in fibre and fermentable foods will favour better bacteria such as Lactobacillus.

Prebiotic food marketing

Fermented milks are currently trending, but most contain added sugar, which encourages the growth of undesirable bacteria. In reality, a simple natural yoghurt provides the same benefits as fermented milk and is cheaper too. It’s also common to see milk enriched with inulin, but if your diet already includes tubers (potatoes, sweet potatoes), onions, bananas, cereals, fruit, and other vegetables, you’re already consuming prebiotic foods that naturally contain these beneficial substances—and they’re more affordable.

In some recipes I’ve mentioned that eating cooked and cooled potatoes is a source of prebiotics, as the starch becomes resistant and can reach the intestine without being broken down in the stomach. So even something as simple as a potato salad or a classic Russian salad is an example of how we’re eating prebiotic foods without even realising it.

So, to sum up: eat tubers, fermented foods, fruits, legumes, and vegetables daily—what I always recommend—and your gut flora will stay in good condition.