Nat. Microbiol. 4, 623–632 (2019)

Science 364, eaau6323 (2019)

Adding to the growing appreciation of the gut–brain connection, a group of researchers in Belgium and Norway analyzed data from the stool microbiomes of the Belgian and Flemish Gut Flora Project cohort and the Dutch LifeLines DEEP cohort, along with information on quality of life and depression. They found that certain species of bacteria were associated with depression and quality of life and that the metabolic products were also linked to measures of mental health.

In another study, a group in the United States identified two successive metabolic pathways in human gut microbiome bacteria that metabolize the Parkinson’s disease therapy l-dopa, thereby limiting its bioavailability for treatment in the brain. They identified a compound that inhibits this reaction and could be explored as a therapeutic to be given alongside l-dopa.