Cross-sectional associations between healthy and unhealthy plant-based diets and metabolic syndrome in three distinct French populations, a meta-analysis.

Prior studies have shown that plant-based diets are associated with lower cardiovascular risk. However, these diets encompass a large diversity of foods with contrasted nutritional quality that may differentially impact health. We aimed to investigate the pooled cross-sectional association between metabolic syndrome (MetS), its components, and healthy and unhealthy plant-based diet indices (hPDI and uPDI), using data from two French cohorts and one representative study from the French population. This study included 16,358 participants from the NutriNet-Santé study, 1,769 participants from the Esteban study and 1,565 participants from the STANISLAS study who underwent a clinical visit. The MetS was defined according to the International Diabetes Federation definition. The associations between these plant-based diet indices and MetS were estimated by multivariable Poisson and logistic regression models, stratified by gender. Meta-analysis enabled the computation of a pooled Prevalence Ratio. A higher contribution of healthy plant foods (higher hPDI) was associated with a lower probability of having MetS (PRmen: 0.85; 95% CI: 0.75-0.94, PRwomen: 0.72; 95% CI: 0.67-0.77), elevated waist circumferences and elevated blood pressure. In women, a higher hPDI was associated with a lower probability of having elevated triglycerides, low HDL-cholesterolemia and hyperglycemia; and a higher contribution of unhealthy plant foods was associated with a higher prevalence of MetS (PRwomen: 1.13; 95% CI: 1.01-1.26) and elevated triglycerides. A greater contribution of healthy plant floods was associated with protective effects on metabolic syndrome, especially in women. Gender differences should be further investigated in relation to the current sustainable nutrition transition.