Prebiotics are natural, non-digestible dietary fibers that selectively stimulate the growth and activity of beneficial gut bacteria. Unlike probiotics, which are live microorganisms, prebiotics are food components that serve as "food" for good bacteria. Research on prebiotics began at the end of the 20th century when it was observed that certain fibers had a positive effect on the composition of the gut microbiota and human health.
How Prebiotics Work
Once in the gut, prebiotics are not broken down by enzymes in the stomach or small intestine, so they reach the large intestine unchanged. There, they are fermented by beneficial bacteria (mostly bifidobacteria and lactobacilli), which use prebiotics as an energy source. During fermentation, short-chain fatty acids (e.g., butyric acid) are produced, which contribute to the health of the intestinal lining, regulate pH, reduce inflammatory processes, and positively affect the immune system.
Main Types of Prebiotics
The most common prebiotics are:
- Inulin – a natural plant fiber obtained from chicory, Jerusalem artichokes, and onions.
- Fructooligosaccharides (FOS) – short fructose chains found in garlic, bananas, and artichokes.
- Galactooligosaccharides (GOS) – derived from milk sugar (lactose), often added to infant formula.
Each type has a different effect on the gut microbiota and specific species of beneficial bacteria.
Sources of Prebiotics in Food
Prebiotics are naturally abundant in various plant-based products. The highest concentrations are found in:
- Vegetables and fruits: chicory, Jerusalem artichokes, onions, garlic, leeks, asparagus, bananas, apples.
- Grains: whole-grain wheat, oats, barley, rye.
- Other sources: legumes (beans, peas, lentils), nuts, seeds.
A varied and balanced diet ensures an adequate daily intake of prebiotics.
Health Benefits of Prebiotics
Prebiotics positively affect the digestive system by promoting the multiplication of good bacteria, improving intestinal peristalsis, and helping to prevent constipation. They contribute to a stronger immune system by participating in the protection of the intestinal lining and inhibiting the growth of pathogenic bacteria. Prebiotics can also help regulate blood glucose and cholesterol levels, thus being important for metabolic health.
Recommendations for Prebiotic Consumption
Adults are recommended to consume about 3–10 g of prebiotics per day, but optimal amounts depend on individual tolerance. Prebiotics can be obtained from food or supplements. It is important to increase the amount of prebiotics gradually to reduce the risk of adverse reactions. Common consumption mistakes include taking too much at once or insufficient fluid intake.
Prebiotics for Different Age Groups
For children, prebiotics are important for the formation of the gut microbiota, especially for infants consuming formula with GOS. For adults, they help maintain the balance of the digestive and immune systems. For older adults, prebiotics can contribute to a slower development of gut dysbiosis, better gut function, and stronger immune protection.
Possible Side Effects
When starting to consume more prebiotics, digestive disturbances may occur: bloating, gas accumulation, discomfort, or looser stools. Some individuals may be more sensitive to certain types of prebiotics. To avoid adverse reactions, it is recommended to increase prebiotic intake gradually and observe the body's reaction.
Prebiotics and Chronic Diseases
Prebiotic consumption is associated with a lower risk of obesity and metabolic syndrome, as they help regulate blood sugar levels and positively affect satiety. Prebiotics can also be beneficial for the prevention of cardiovascular diseases, as some of them help reduce blood cholesterol levels. According to some studies, prebiotics can reduce the symptoms of inflammatory bowel diseases, but individual effects may vary.
Prebiotic Supplements
Prebiotic supplements come in various forms – powders, capsules, and drinks, usually containing inulin, FOS, or GOS. Supplements can be useful when too few prebiotics are obtained from food or when there are special needs (e.g., gut microbiota imbalance). Before choosing supplements, it is important to assess safety, possible ingredients, and individual tolerance.
Combining Prebiotics with Probiotics
When prebiotics and probiotics are consumed together, this combination is called synbiotics. Synbiotics can provide a stronger effect on the gut microbiota, as prebiotics help probiotics survive and multiply in the gut. In practice, it is advisable to consume a varied diet that includes both prebiotics and natural probiotic sources (e.g., fermented products).
Properly incorporating prebiotics into the diet can strengthen the diversity of the gut microbiota and maintain overall body health, but individual needs may vary depending on age, health status, and dietary habits.
