Examining the effects of consuming muffins containing brewer's spent grains on fiber intake, healthy eating index scores, and inflammatory biomarkers in healthy adults

Brewer’s spent grain (BSG) is the barley byproduct that is created during the beer brewing process. This nutrient-dense waste product is not only rich in dietary fiber, but also protein. This study evaluated the impact of consuming BSG on dietary fiber intake, Healthy Eating Index (HEI) scores as well as the pro-inflammatory cytokines IL-6, IL-1beta, and anti-inflammatory cytokine IL-10 in healthy adults (n = 37; 26.0 ± 4 y; BMI 22.9 ± 3 kg/m2) using secondary data from a single-blinded, randomized, controlled study. Diet records were collected for two weekdays and one weekend day at three timepoints from participants who either consumed muffins with 0 g BSG (control; n =18) or 10.4 g BSG (treatment; n=19) daily for eight weeks. These diet records were evaluated to determine dietary fiber intake as well as HEI scores. The inflammatory cytokines were analyzed using fasting serum samples collected at baseline and final time points of the study. While the mean dietary fiber intake was increased within the BSG group (5g/day, 26% p = .003), no significant effects were found on HEI scores, IL-6, IL-10, and IL-1b. Though significance was not achieved, within-group IL-10 and IL-1b increased in concentration were approaching significance (p = .060 and p = .066) in the treatment group. There were also moderate to strong, positive, and significant correlations observed between the change within the interleukins as well as between moderate correlations between fiber and HEI scores. In conclusion, BSG does not significantly affect inflammatory biomarkers, fiber intake, or contribute to improvements in overall healthy diets in a healthy population in an 8-week timeframe while consuming this amount.