Enzymatically modified isoquercitrin (EMIQ), a water-soluble quercetin, has been shown to intensify muscle hypertrophy in mice. We investigated the effect of EMIQ in supplementary protein powder on athlete body composition. Forty Japanese males who played American football (age: 19.8 ± 1.4 years; body height: 174.1 ± 6.0 cm; body mass: 75.5 ± 10.7 kg) were assigned to a randomized, placebo-controlled, double-blind trial of parallel group. Participants received either EMIQ in whey protein (EW, n = 19) or contrast whey protein (W, n = 20) 6 days per week over 4 months. Body composition was assessed using dual-energy X-ray absorptiometry. Markers of oxidative stress, derivatives of reactive oxygen metabolites (d-ROMs) and biological antioxidant potential (BAP), were assessed using a free radical analytical system. Data were analyzed using a univariate and repeated measures general model statistics. After 4 months, changes in lower limb fat-free mass and muscle mass were significantly greater in the EW group than in the W group (mean change ±95% CI; W: 324.1 ± 284.3, EW: 950.3 ± 473.2, p = 0.031, W: 255.7 ± 288.6, EW: 930.9 ± 471.5, p = 0.021, respectively). Moreover, the EW group exhibited a significantly higher BAP/d-ROMs ratio, antioxidation index, than the W group after 4 months (mean change ± SD; W: 8.8 ± 1.1, EW: 10.3 ± 2.8; p = 0.028). No significant differences in body mass, lean body mass, fat mass, or lower limb fat mass were observed between the groups. Ingestion of EMIQ in supplementary protein powder for 4 months exerts antioxidant effects and increases muscle mass among American football players. University Hospital Medical Information Network Clinical Trial Registry, UMIN000036036. Retrospectively registered in 2019.

Amazake is a traditional Japanese beverage. Its main ingredients are sake cake and rice malt. In this study, we examined the effect of sake cake and rice malt on the intestinal barrier function and gut microbiota. BALB/c mice were fed a control diet or a diet containing a mixture of sake cake and rice malt powder (SRP) for four weeks. Fecal IgA values did not change between groups, but the fecal mucin level was significantly greater in the SRP-fed group. Gene expression analysis in the ileum by real-time PCR demonstrated Muc2 expression did not change, while the Muc3 expression was upregulated in the SRP-fed group. Furthermore, microbiota analysis demonstrated a change by SRP intake at the family level, and the proportion of Lactobacillaceae significantly increased in the SRP-fed group. At the genus level, the proportion of Lactobacillus also significantly increased in the SRP-fed group. These results suggest that the intake of a mixture of sake cake and rice malt improves intestinal barrier function by increasing mucin levels and inducing changes in intestinal microbiota.

Protein intake has been reported to secrete insulin and lower glucose levels, but the effect of carbohydrate and protein co-ingestion on amino acid absorption has not been well documented. A randomized, placebo-controlled, single-blinded, crossover trial was conducted to evaluate the effect of sucrose on blood amino acid levels. Eleven volunteers (both sexes aged 20–60 years with body mass index 21.4 ± 2.4 kg/m²) randomly received one of four test solutions: water (P-group), 10 g sucrose (S-group), 10 g whey protein (W-group), or 10 g whey protein + 10 g sucrose (W-S-group), and blood amino acid concentration, glucose levels, and insulin levels were monitored over 180 min. Following the wash-out period, randomized treatment and blood parameter monitoring were repeated. Consequently, amino acid concentration was significantly lower in the S-group than in the P-group, showing that single ingestion of sucrose decreased blood amino acid levels in a fasted state. However, there was no significant difference between blood amino acid levels of the W- and W-S-groups, suggesting that co-ingestion of sucrose does not affect blood amino acid concentration. Insulin levels were significantly higher in the W-S than in the S-group, and glucose levels were significantly lower in the W-S- than in the S-group, suggesting positive impact on glycotoxicity by reducing blood glucose levels. Therefore, whey protein co-ingestion with sucrose suppresses glucose levels and increases insulin levels as opposed to the sucrose ingestion, but does not affect amino acid absorption of whey protein, indicating that this co-ingestion may not be a problem for protein supplementation.