By: Mark Lange, PhD
Recently a team of researchers completed a study to investigate whether a whole grain diet alters the gut microbiome and insulin sensitivity as well as the biomarkers of metabolic health and gut functionality. Accumulating evidence from rodent studies points towards the gut microbiota as a mediator of dietary impact on metabolic health, and evidence suggests that the microbial degradation of whole grains may exert beneficial effects on the host metabolism. Read on to find out more.
A randomized crossover trial of 50 Danish adults, at risk of developing metabolic syndrome, studied the effects of consuming whole grain products instead of refined grain products in their diet. The trial consisted of two 8-week dietary intervention periods comprising whole grain diet and refined grain diet, separated by a washout period of ≥6 weeks. The response to the interventions on the gut microbiome composition and insulin sensitivity as well on measures of glucose and lipid metabolism, gut functionality, inflammatory markers, anthropometry and urine metabolomics were measured and assessed.
The 8-week study found that participants had less inflammation in their bodies when eating 179 ± 50 g/day of whole grains. They also ate less food in general, perhaps due to an increase in the feeling of fullness. The authors concluded that, compared to a refined grain diet, a whole grain diet reduced energy intake and body weight. In addition, inflammation markers CRP and IL-6 were reduced. No significant alteration in the participants’ gut microbiomes or gut function were observed.
What It Means:
Compared with refined grain diet, whole grain diet did not alter insulin sensitivity and gut microbiome but did reduce body weight and systemic low-grade inflammation. This means that – because of the beneficial effects of whole grain consumption on blood markers of subclinical inflammation in adults at risk of developing metabolic syndrome – higher intake of whole grains can be encouraged in those at risk of inflammation-related diseases.