Potential of dietary polyphenols for protection from age-related decline and neurodegeneration: a role for gut microbiota?

Many epidemiological studies have shown the beneficial effects of a largely plant-based diet, and the strong association between the consumption of a Mediterranean-type diet with healthy aging including a lower risk of cognitive decline. The Mediterranean diet is characterized by a high intake of olive oil, fruits and vegetables and is rich in dietary fiber and polyphenols - both of which have been postulated to act as important mediators of these benefits. Polyphenols are large molecules produced by plants to protect them from environmental threats and injury. When ingested by humans, as little as 5% of these molecules are absorbed in the small intestine with the majority metabolized by the gut microbiota into absorbable simple phenolic compounds. Flavan-3-ols, a type of flavonoid, contained in grapes, berries, pome fruits, tea, and cocoa have been associated with many beneficial effects on several risk factors for cardiovascular disease, cognitive function and brain regions involved in memory formation. Both preclinical and clinical studies suggest that these brain and heart benefits can be attributed to endothelial vascular effects and anti-inflammatory properties among others. More recently the gut microbiota has emerged as a potential modulator of the aging brain and intriguingly polyphenols have been shown to alter microbiota composition and be metabolized by different microbial species. However, there is a need for well controlled studies in large populations to identify predictors of response, particularly given the vast inter-individual variation of human gut microbiota.

Beyond the dyad: making Developmental Origins of Health and Disease (DOHaD) interventions more inclusive.

Pregnant women, children under 2 and the first thousand days of life have been principal targets for Developmental Origins of Health and Disease interventions. This paradigm has been criticized for laying responsibility for health outcomes on pregnant women and mothers and through the thousand days focus inadvertently deflecting attention from other windows for intervention. Drawing on insights from the South African context, this commentary argues for integrated and inclusive interventions that encompass broader social framings. First, future interventions should include a wider range of actors. Second, broader action frameworks should encompass life-course approaches that identify multiple windows of opportunity for intervention. Using two examples - the inclusion of men, and engagement with adolescents - this commentary offers strategies for producing more inclusive interventions by using a broader social framework.