Probiotic supplement may improve cognition, mood in older adults

Supplementation with probiotics appears to induce an acute effect on reaction times during executive function, hinting at the possibility of preventing the development of depression among older adults, according to a study.

This randomized, placebo-controlled, crossover trial involved 30 healthy older adults in exploring the acute (1 day) and chronic (8 weeks) effects of a probiotic supplement on cognitive domains of memory and executive function, as well as mood measures of stress, anxiety, depression, and cognitive reactivity to sad mood.

The authors also conducted 16s rRNA sequencing of stool samples before and after chronic intervention to analyse the potential effects of probiotics supplementation on the gut microbiota.

Acute supplementation with probiotics resulted in faster reaction times on cognitively demanding trials during a task of executive function (–64.91 ms, 95 percent confidence interval [CI], –115.70 to –14.15). 

Likewise, chronic probiotics supplementation correlated with improvement in cognitive biases, such as hopelessness (–0.97, 95 percent CI, –1.72 to –0.23), rumination (–1.58, 95 percent CI, –2.86 to –0.29), and aggression (–1.57, 95 percent CI, –2.63 to –0.51), that contribute to reactivity to sad mood and thus vulnerability to depression. This may also lead to improved executive function under higher cognitive demand (0.43 percent, 95 percent CI, –0.53 to 1.38).

“The current work provides novel evidence for an acute effect of probiotics on reaction times during executive function, which should be replicated in future work,” the authors said. 

“Additionally, this work replicates previous findings of improved cognitive reactivity to sad mood following chronic probiotic supplementation, indicating probiotics may reduce the risk of developing depression in a healthy ageing population,” they added.