The research – first published in the journal Clinical and Translational Gastroenterology – found that probiotic supplements may bring on stomach pains, bloating, gas and mental fogginess when consumed regularly. The reason? Bacterial overgrowth (when the ‘good’ microbes multiply in excess, colonising the small intestine and stomach.)
The study’s lead author Dr Satish Rao and his colleagues analysed 30 adults who were taking probiotics. While all participants suffered from gas and bloating, 22 had cognitive issues such as confusion and difficulty concentrating. Some were even forced to quit their jobs due to the severity of their brain fog, which would often last for hours after eating.
Interestingly, the researchers established that the participants all had large communities of bacteria in their small intestine, as well as abnormally high levels of D-lactic acid (a by-product of probiotic bacteria that can be temporarily toxic to brain cells.)
The participants were prescribed antibiotics and asked to stop taking the supplements, which in most cases, resulted in relief from their symptoms.
“What we now know is that probiotic bacteria have the unique capacity to break down sugar and produce D-lactic acid,” explained Dr Rao. “So, if you inadvertently colonise your small bowel with probiotic bacteria, then you have set the stage for potentially developing lactic acidosis and brain fogginess.”
So, what’s a girl looking to improve her gut health without overdoing it to do? Dr Rao suggests chowing down on kimchi, dark chocolate and yoghurt as these ingredients are relatively low in good bacteria.
“Probiotics should be treated as a drug, not as a food supplement,” he added. Food for thought.