Prof. Hania Szajewska PhD, The Medical University of Warsaw, Department of Paediatrics, Poland and Prof. Seppo Salminen PhD, Faculty of Medicine, Functional Foods Forum, University of Turku, Finland
In their recent study, Rao and colleagues1 incriminated probiotics in the induction of D-lactic acidosis (1). Many who benefit from probiotics could be frightened—on the basis of this report—into stopping them, with potentially negative impacts on their health (2). Some probiotic bacteria, including some specific components of the intestinal microbiota, may produce D-lactic acid. Indeed, if plasma D-lactic acid rises sufficiently, it is clinically relevant, causing D-lactic acidosis. D-lactic acidosis has mainly been observed in subjects with short bowel syndrome. However, some authorities have regulated the use of D-lactic acid producing bacteria in infant and weaning foods, but the reasoning for normal infant population has been debated. Even in adults, the safety of D-lactic acid producing bacteria has been challenged, but apart from short bowel patients no evidence on clinical problems has been reported (3).
For this reason, we conducted a review and examined whether D-lactic acid-producing bacteria, acidified infant formulas and fermented infant formulas were potential causes of paediatric D-lactic acidosis (4).
We identified five randomised controlled trials conducted between 2005-2017 with 544 healthy infants. Additionally, some case reports and experimental studies were considered. No clinically relevant adverse effects of D-lactic acid-producing probiotics or fermented infant formulas in healthy children were identified. The only known cases of paediatric D-lactic acidosis were observed in patients with short bowel syndrome (4). It is of importance that human milk also contains lactic acid bacteria and bifidobacteria, some of which may produce D-lactic acid. Some stress situations, such as exercise, may elevate human milk lactate concentrations. Thus, breast milk D-lactate content needs to be analysed more carefully to compare with fermented infant formulas.
Taken together, our results suggest that neither the probiotics that were evaluated in the studies we reviewed nor fermented infant formulas cause D-lactic acidosis in healthy children.
- Rao, S. S. C., Rehman, A., Yu, S. & Andino, N. M. Brain fogginess, gas and bloating: a link between SIBO, probiotics and metabolic acidosis. Transl. Gastroenterol.9, 162 (2018). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6006167/
- Sanders, M. E., Merenstein, D. & Merrifield, C. A. Probiotics for human use. Bull.43, 212–225 (2018). https://onlinelibrary.wiley.com/doi/10.1111/nbu.12334
- Quigley E.M.M, Pot B., Sanders M.E. ‘Brain fogginess’ and D-lactic acidosis: probiotics are not the cause. Transl. Gastroenterol.9, 187 (2018). https://www.nature.com/articles/s41424-018-0057-9
- Łukasik, J., Salminen S., Szajewska H. Rapid review shows that probioticsand fermented infant formulas do not cause D-lactic acidosis in healthy children. Acta Pediatrica 107, 1322-1326 (2018). https://www.ncbi.nlm.nih.gov/pubmed/29603358