Dietary patterns affect Parkinson's disease via the microbiota-gut-brain axis

Globally improved life expectancy has led to a significant increase in the incidence of Parkinson's disease (PD). It is widely thought that dietary factors are crucial modifiers of the PD risk. Previous studies of the association between PD and diet have mainly focused on single food components and specific nutrients, whereas comprehensive reviews of the role of general dietary patterns in PD are limited. Thus, this review discusses the effects of adopting a Western, Mediterranean, ketogenic, protein-restricted, calorie-restricted, intermittent fasting, or fast-mimicking diet on PD, and summarizes the underlying mechanisms by which these dietary patterns affect molecular markers of the disease. Specifically, we examine the potential associations among these dietary patterns, the gut microbiome composition, and PD development. Furthermore, we suggest a framework that can be used to develop personalized microbiota-directed dietary interventions for PD based on the individual gut microbiome composition. The Mediterranean diet reduces the risk of PD with favorable alternations of intestinal microbiota, increases levels of SCFAs, and reduces the TMAO level. Calorie restriction and Fasting-mimicking diet show some neuroprotective effects on PD via increasing β-HB, FGF21, and Ghrelin levels. Meanwhile, both ketogenic and protein-restricted diets show a striking effect on ameliorating motor impairment and fluctuations. Conversely, Western diet correlates with an increased incidence of PD and exacerbates the severity of PD with unfavorable changes of intestinal microbiome and increases neuroinflammation. Clarifying these roles of dietary patterns in PD will be meaningful for future personalized-dietary interventions in patients with PD.