• Fibers— the building blocks for your gut flora. Indigestible carbohydrates from plant-based foods.
• Prebiotics — a specific group of fibers that can serve as a food source for gut bacteria. 
• Probiotics— living, beneficial bacteria themselves (in food or supplements).
• Postbiotics— the substances that your gut bacteria produce when they ferment fibers and prebiotics.
• Synbiotics— a combination of pro- and prebiotics in one product.

1. Fibers — the basis of everything 

Fibers are indigestible parts of plant-based foods. Your own digestive enzymes cannot break them down, but your gut bacteria can. Your gut bacteria ferment fibers, producing short-chain fatty acids (SCFAs). These substances play a role in the intestinal wall, theimmune systemand the brain.

There are two main types: soluble fibers (oats, legumes, fruit, flaxseed) which form a gel-like structure in water, and insoluble fibers (whole grains, vegetable peels, nuts) which provide bulk and regulate bowel movement speed. A varied diet provides both.

A frequently cited guideline is 30-40 grams of fiber per day. The average intake is often around 20 grams — so almost everyone can consume more.

Source:EU Register on nutrition and health claims(Regulation (EU) 432/2012 — officially authorized health claims). 

Prebiotics are a specific group of fibers (or sometimes other substances) that are not digested by your own intestinal cells, but are digested by certain intestinal bacteria such as Bifidobacterium and Lactobacillus.

Known prebiotics 

• Inulin (from chicory, garlic, onion, asparagus, leek)
• Fructo-oligosaccharides (FOS) (from fruit, legumes, onion)
• Galacto-oligosaccharides (GOS) (from milk, legumes)
• Resistant starch (from cooked and cooled potatoes, bananas, legumes)
• Beta-glucan (from oats, barley, mushrooms)

For those who want to increase their fiber intake, a prebiotic supplement (for example, inulin powder or FOS) can be a good addition. Start gradually — too much too suddenly can cause flatulence.

3. Probiotics — the live bacteria themselves 

Probiotics are live microorganisms. Important families:

• Lactobacillus — mainly in the small intestine; one of the best-known families. 
• Bifidobacterium — mainly in the large intestine; plays a role in fiber fermentation and immunity.
• Saccharomyces boulardii — a yeast (not a bacterium); mainly used for travel-related digestive complaints and after antibiotics.

In what situations do people choose probiotics? 

• During and after a course of antibiotics (to support the flora)
• When traveling to countries with different hygiene conditions (see blog July #1)
• During periods of stress or after an illness
• For chronic intestinal complaints (in consultation with a doctor)
• For a one-sided diet or after intensive alcohol consumption

Important: no recognized health claims are allowed for probiotics. The EFSA sets strict requirements, meaning that claims about an effect are not allowed on labels. In practical terms, this means: products are described neutrally and you choose based on strain, dosage (expressed in CFU — colony forming units) and composition.

Postbiotics 

These are the substances that are created when probiotics ferment fibers — especially short-chain fatty acids, peptides, and cell wall fragments. Postbiotics are therefore not living bacteria, but their "work products". In supplements, they are still relatively new.

Synbiotics 

A combination of probiotics and prebiotics in one product. Synbiotics can be practical because you take both at once.

Which do you choose — fibers, prebiotics, or probiotics? 

Start with the basics: nutrition 

For most people without specific complaints, increasing fiber intake (vegetables, fruit, legumes, whole grains) and adding fermented products (yogurt, kefir, sauerkraut) is a logical first step. This automatically covers all four categories.

Prebiotic supplement: for specific fiber goals 

For those who find it difficult to meet fiber norms through diet, a prebiotic supplement (inulin, FOS, GOS) is a good addition.

During antibiotic treatment, travel, chronic complaints, or stress, people sometimes opt for a probiotic supplement. Preferably choose a multi-strain product with sufficient CFU (usually 10-50 billion per serving). 

During antibiotic treatment, travel, chronic complaints, or stress, a probiotic supplement is targeted support. Preferably choose a multi-strain product with sufficient CFU (usually 10-50 billion per serving).

Synbiotics: for those who want convenience 

For those who want to cover all three in one product, a synbiotic product is practical. Pay attention to the composition — sufficient CFU and relevant prebiotic component.

Fibers, prebiotics, probiotics, postbiotics, and synbiotics are different categories related to gut flora. The basis lies in nutrition — varied, rich in fiber, with fermented products. Supplements can be an addition in specific situations: during or after antibiotics, when traveling, during stress, or when you don't get enough fiber through your diet. Which category suits you depends on your situation.

Disclaimer: This article is informative in nature and does not replace medical advice. A nutritional supplement is not a substitute for a varied and balanced diet and a healthy lifestyle. In case of doubt or medication use: consult a doctor or pharmacist. Do not exceed the recommended daily dose. Keep out of reach of young children.