Nut and legume consumption and human health: an umbrella review of observational studies

Consumption of nuts and legumes has been associated with several health benefits. The aim of this study was to systematically review existing meta-analyses of observational studies on nut and legume intake and non-communicable diseases, and assess the level of evidence. Out of the six meta-analyses focussed on legume and 15 on nut intake, a possible association with decreased risk of colorectal adenoma and coronary heart disease was found for higher legume consumption, and a decreased risk of cardiovascular and cancer mortality, colon cancer, hypertension and ischaemic stroke for higher nut consumption. The association between legume consumption and cardiovascular diseases (CVDs), as well as nut consumption and risk of cancer, CVD incidence and all-cause mortality, was deemed as "limited" due to heterogeneity between results and/or potential confounding factors. General benefit towards better health can be observed for nut and legume consumption. Further studies are needed to better elucidate potential confounding factors.