Probiootti

Probiootti, or probiotic, refers to live microorganisms that, when consumed in adequate amounts, confer a health benefit to the host. The most studied groups are lactic acid bacteria such as Lactobacillus and Bifidobacterium species, and the yeast Saccharomyces boulardii. Probiotics are found in fermented foods like yogurt, kefir, sauerkraut, and miso, as well as in dietary supplements.

Potential benefits vary by strain and condition. Evidence supports prevention of antibiotic-associated diarrhea, and some protection against certain traveler's diarrhea. Benefits have also been investigated for irritable bowel syndrome, inflammatory bowel disease, and other gut-related or immune-mediated conditions. However, effects are strain-specific, and not all products have proven benefits. Recommendations should be guided by current clinical data for specific strains and indications.

Mechanisms of action include competitive exclusion of pathogens, strengthening of the intestinal barrier, modulation of mucosal and systemic immune responses, and production of metabolites such as short-chain fatty acids and bacteriocins. The presence of prebiotics, which are substrates that feed beneficial microbes, can enhance probiotic effects.

Safety and regulation vary by country. Probiotics are generally considered safe for healthy individuals, but may carry risks for immunocompromised or critically ill people, including rare cases of bacteremia or fungemia. Product quality, viability, and accurate labeling are important concerns, as regulatory oversight differs between foods, supplements, and medicinal products. The concept originated in the early 20th century with ideas about gut microbiota contributing to health.