Gut microbes that break down the amino acid tryptophan secrete small molecules called indoles — and these indoles are a key factor in stimulating new neuron growth in the adult brain.

The Tsimane indigenous people of the Bolivian Amazon exhibit a significantly slower decrease in brain volume with age than populations in the U.S. and Europe — this study examines why. 

Lower levels of bile acids and cholesterol precursors were associated with higher brain amyloid deposition and faster brain deterioration, which increased the risk of developing dementia.

Long-term treatment with low-dose resveratrol improves cognitive performance in elderly male rats, with an increase in cerebral blood flow and a decrease in pro-inflammatory pathways in the brain.