Effects of wheat germ supplementation on inflammation, metabolic, and gut health markers in overweight adults
Abstract
Objectives: Overweight and obesity is linked to several metabolic disturbances including type 2 diabetes. Functional foods such as wheat germ (WG) have been shown to improve metabolic markers in animals and humans alike. Our study investigated the effects of wheat germ supplementation on inflammation, metabolic, and gut health markers in overweight adults. Methods: Forty overweight (body mass index = 25.0-30 kg/m2) adults between the ages of 18-45 years old were recruited to participate in this single-blinded randomized controlled study. After initial screening, participants were asked to consume energy balls containing either cornmeal (control) or 30 g of WG daily for 4 weeks. Participants were asked to otherwise maintain their normal diet and physical activity throughout the supplementation period. Anthropometric and metabolic parameters, as well as dietary (3-day food record), medical history, physical activity (Yale Physical Activity Survey), stool measures (Bristol Stool Chart, BSC and the Cleveland Clinic Constipation Scoring System, CSS), gut integrity markers, and fecal bacterial population were assessed at baseline and at the end of the 4-week supplementation period. Results: Thirty-nine participants completed the 4-week supplementation (n = 20 and 19 for the WG and control group, respectively). There were no differences in the lipid profile, but glycated hemoglobin (P = 0.04), insulin (P = 0.03), and homeostatic model assessment of insulin resistance (P = 0.04) were significantly decreased in the WG but not the control group. Additionally, the adipokine resistin, which is correlated with insulin resistance, was also significantly reduced (P = 0.03) by WG supplementation but not the control. There were no changes in stool characteristics between the two groups before and after supplementation as indicated by the BSC and CSS. The phyla Bacteroidetes (P = 0.03) and Proteobacteria (P = 0.048) and the genus Bacteroides (P = 0.03) were significantly decreased in the control group. No significant changes were observed in plasma inflammatory markers, fecal short-chain fatty acid (SCFAs) concentrations, and markers of gut integrity in both supplements. Conclusion: Four weeks of WG supplementation resulted in improvements in markers of glucose homeostasis and reduction of the pro-inflammatory adipokine, resistin. However, these improvements in markers of glucose homeostasis due to WG consumption is not due to changes within the gut (i.e., bacterial population, gut integrity, and SCFAs production). The mechanism by which WG improve glucose homeostasis is unclear at this time and needs to be investigated in future studies. Our findings indicate that WG may be a safe, effective and economical approach to improve glucose homeostasis.
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- OSU Theses [15752]