Wheat germ supplementation has modest effects on gut health markers but improves glucose homeostasis markers in adults classified as overweight: a randomized controlled pilot study

Wheat germ (WG), a by-product of flour milling, is rich in bioactive substances that may help improve health complications associated with increased adiposity. This study investigated the effects of WG on gut health, metabolic, and inflammatory markers in adults classified as overweight. We hypothesized that WG, because of its many bioactive components, would improve gut health, metabolic, and inflammatory markers in overweight adults. Forty adults (18–45 years old) and with BMI between 25-30 kg/m2 participated in this single-blinded randomized controlled pilot study. Participants consumed the study supplements containing 30 g of either cornmeal (Control, CL) or WG daily for 4 weeks. Primary outcome variables were gut health markers including gut microbiota, gut integrity markers and fecal short-chain fatty acids (SCFAs), while secondary outcome variables included metabolic and inflammatory parameters assessed at baseline and at the end of supplementation. Thirty-nine participants (n = 19 and 20 for CL and WG group, respectively) completed the study. The genus Faecalibacterium was significantly higher in the WG group compared to CL post-supplementation but no significant changes in other gut health markers, SCFAs, inflammatory and lipid profiles were observed. Compared to baseline, WG improved markers of glucose homeostasis including insulin (P = 0.02), homeostatic model assessment of insulin resistance (HOMA-IR, P = 0.03), HbA1c (P = 0.07), and the pro-inflammatory adipokine, resistin (P=0.04). However, these parameters post- intervention were not different with control. Our findings suggest that WG supplementation have modest effects on gut health but may provide an economical option for individuals to improve glycemic control.