Does your gut play a role in decision-making? A team of researchers from Maastricht University put it to the test.
They investigated whether taking probiotics (Ecologic® Barrier) would affect risky and future-oriented decision-making in humans’ subjects. The findings of this study are fascinating. It provides the first direct evidence pointing to a functional role of the gut-brain axis in risk-taking decision making behaviour.
Promising results in previous studies
Past studies have indicated that gut bacteria are involved in a bidirectional interaction with the brain; hence the so called ‘microbiota-gut-brain axis’. The ecological balance of the gut microbiota is known to affect brain development, cognitive performance, mood, reactivity to stress and socialization, and it even plays a role in certain psychopathologies. There is accumulating evidence that influencing gut bacteria has an effect on cognitive, emotional and behavioural processes.
The study of the relationship between gut microbiota and decision-making in animal models has shown promising results. Germ-free rodents exhibit increased risk-taking behaviour, which is reversed to normal levels after their gut microbiota is normalized via fecal transplantation or probiotic administration. The administration of Ecologic® Barrier for six weeks in rats led to a significant reduction in risk-taking behaviour. Also in humans, a significant reduction in risk-taking behaviour after taking a probiotic (Ecologic® 825) for four weeks has already been observed.
Study design with gambling tests
Nevertheless, there is still a lack of understanding of the effects of this system on decision-making. The researchers who did this study hypothesized that by influencing the gut microbiota composition with probiotics they could affect risk-taking behaviour and intertemporal choices. These changes would occur via the gut-brain axis leading to changes in brain activity. To address this, the researchers conducted a double-blind study. The study included a period of 30 days during which participants took daily doses of either Winclove’s probiotic formula Ecologic® Barrier or a placebo. Participants completed questionnaires in two experimental sessions (on days 1 and 30) to control for diet, arousal, self-control, and mood effects as well as to provide alternative measures of time and risk preferences. Specifically, the researchers used the Maastricht Gambling Task (MGT) and the Maastricht Choice Game (MCG) which consists of computer tasks to elicit and estimate risk-taking behaviour and intertemporal choices, respectively.
Fifty-seven healthy adults (29 women and 28 men), with no reported psychological, psychiatric or gastric disease, with an average age of 23.4 years finished the experiment.
Treatment options for ADHD and addictions
The results confirm the relationship between changes in the gut-brain axis and decision-making. Firstly, as compared to participants in the placebo group , those who underwent the probiotics protocol were significantly less likely to choose risky options. This indicates a significant decrease in risk-taking behaviour. Secondly, after the prolonged use of probiotics, the participants were significantly more likely to make future-oriented choices, investing more in delayed options than the participants who received a placebo for the same period were. The authors suggested the potential for the therapeutic use of probiotics in patients with attention deficit and hyperactivity disorder (ADHD), addictions, or depression. However, the mechanism behind the communication between the gut and the brain during decision-making is still unclear. A deeper understanding of the underlying mechanisms will help to refine the clinical use of probiotic supplements in the future. A follow-up study is expected by the same research group to unravel the details behind this interesting effect of probiotics.