LDL-cholesterol lowering effects of wholegrain rye compared with wholegrain wheat diets are modified
Wholegrain rye may improve blood glucose regulation and blood lipid composition. The effects are hypothesized to be mediated through fermentable dietary fiber and lignans. In recent studies, the role of gut microbiota has been highlighted as a potential modifier of health effects of wholegrain intake.
In this study, several researchers from the Nordic Rye Forum were involved to investigate the effect of wholegrain rye (alone or supplemented by lignans) and wholegrain wheat diets on glucose tolerance and other cardiometabolic risk factors. Effects of the intervention diets were analyzed in relation to gut microbiota composition. The study subjects were men with higher risk of developing metabolic disorders, who during eight weeks consumed the rye (4 wks alone, 4 wks supplemented by lignans) or the wheat diets. After the eight week period, the diets were switched during eight more weeks; a so called cross-over setup, where the subjects serve as their own controls.
The effects on glucose metabolism were similar between the different wholegrain diets, irrespective of lignan supplementation. However, depending on variations in the subjects' gut microbiota, the both rye diets lowered LDL-cholesterol during a defined time-period compared with the wheat diet.