After the fourth decade of life, muscle and bone mass decrease by ~ 1%-2% per year. This age-related reduction in muscle and bone (including muscle density and bone geometry, as indicators of muscle and bone quality) increases the risk of falls and fractures. Approximately one-in-three older adults experience a fall each year, with many experiencing multiple falls. Falls may lead to physical inactivity and premature morbidity. Therefore, lifestyle interventions that improve properties of muscle and bone may potentially reduce the risk of falls and fractures in older adults.

The MaPLE study was a randomized, controlled, crossover trial involving adults ≥60 y.o. (n = 51) living in a residential care facility during an 8-week polyphenol-rich (PR)-diet. Results from the MaPLE trial showed that the PR-diet reduced the intestinal permeability (IP) in older adults by inducing changes to gut microbiota (GM). The present work aimed at studying the changes in serum metabolome in the MaPLE trial, as a further necessary step to depict the complex crosstalk between dietary polyphenols, GM, and intestinal barrier.