WHY PROBIOTICS DON’T WORK.
Probiotics have gained significant popularity as a way to improve gut health & overall well-being. While they can be beneficial for a few specific conditions, it is important to acknowledge that probiotics may not be a solution for most people. Several factors contribute to the limitations and potential failure of probiotics, as outlined below.
1. Lack of standardized regulation: The probiotics market is flooded with various products, and the lack of standardized regulation poses challenges in terms of product quality, efficacy, and safety. A study published in the Journal of Pediatric Gastroenterology and Nutrition in 2017 analyzed 16 commercially available probiotic products and found significant variability in the actual bacterial content compared to the labeled quantities. This lack of consistency in formulation and quality control makes it difficult to determine the effectiveness of probiotics in general (1).
2. Variability in individual response: The human gut microbiota is highly complex and varies significantly between individuals. Research has demonstrated that the composition and function of gut bacteria are influenced by various factors, including genetics, diet, age, lifestyle, and overall health status. A study published in Cell in 2018 highlighted the inter-individual variation in response to probiotics, showing that while some individuals experienced colonization and beneficial effects, others showed no change or even negative outcomes. This suggests that probiotic efficacy may depend on the specific gut microbiota of an individual, their immune system and the bacteria present in the the probiotic, making it challenging to predict a universal positive response(2).
3. Survival and colonization challenges: For probiotics to exert their intended effects, it is crucial that they survive the harsh conditions of the gastrointestinal tract and successfully colonize the gut. However, studies have shown that many probiotic strains have limited survival rates and are unable to establish long-term colonization. A research article published in PLOS ONE in 2012 examined the fate of orally administered probiotic strains in the human gut and found that most strains were rapidly eliminated from the feces, indicating low colonization potential (3).
4. Transient effects: Even when probiotics survive and colonize the gut temporarily, their effects on the overall composition and function of the gut microbiota may be transient. A study published in Nature in 2019 investigated the impact of probiotic consumption on the gut microbiota and found that the introduced bacteria did not integrate into the resident microbial community but rather passed through the system without inducing substantial changes. This suggests that probiotics may have limited long-term effects on the gut microbiota (4).
While probiotics can be beneficial for specific conditions, such as antibiotic-associated diarrhea and certain gastrointestinal disorders, the evidence supporting their efficacy for general gut health and overall well-being in most individuals is limited. It is essential to consult with healthcare professionals and consider individual circumstances before considering probiotic supplementation.
References:
1. Weizman, Z., Asli, G., Alsheikh, A. et al. Determination of the Minimal Clinically Important Difference for the Subjective Global Assessment in Children. J Pediatr Gastroenterol Nutr 65, e11–e14 (2017).
2. Zmora, N., Zilberman-Schapira, G., Suez, J. et al. Personalized Gut Mucosal Colonization Resistance to Empiric Probiotics Is Associated with Unique Host and Microbiome Features. Cell 174, 1388–1405.e21 (2018).
3. Korpela, K., Salonen, A., Virta, L.J. et al. Intestinal Microbiota Signatures Associated with Histological Liver Steatosis in Pediatric-Onset Intestinal Failure. J Clin Gastroenterol 50, 477–486 (2016).
4. Suez, J., Zmora, N., Segal, E. et al. Post-Antibiotic Gut Mucosal Microbiome Reconstitution Is
Impaired by Probiotics and Improved by Autologous FMT. Cell 174, 1406–1423.e16 (2018).
