Journal of nutritional science and vitaminology最新文献

This study investigated the effects of 20-hydroxyecdysone (20E) derived from Asparagus officinalis extract on substrate utilization and metabolic health in young males undergoing resistance training (RT). Twenty healthy males were randomly assigned in a double-blind design to receive either a placebo (PLA; n=10) or 30 mg/d of 20E (n=10) for 12 wk, during which all participants performed supervised RT three times per week. Assessments were conducted at baseline and post-intervention, including body composition, substrate utilization, fasting glucose, insulin, free fatty acids (FFAs), and the quantitative insulin sensitivity check index (QUICKI). The 20E group showed significant reductions in arm (p<0.01), leg (p<0.05), and abdominal fat (p<0.05), with arm fat reduction significantly greater than in the PLA group (p<0.05). Fat oxidation increased at rest and during exercise in the 20E group (p<0.01), with between-group differences evident only at 40% of V•O₂peak (p<0.05). Furthermore, 20E supplementation was associated with favorable metabolic changes, including reductions in fasting insulin (p<0.01) and plasma FFAs (p<0.05), alongside an increase in QUICKI (p<0.01). These findings suggest that 20E supplementation, when combined with RT, may support regional fat reduction, promote fat oxidation, and improve insulin sensitivity, thereby offering potential benefits for metabolic health.

Post-traumatic wound infection is commonly observed in trauma patients and has a poor prognosis. Vitamin D is a significant modulator of the immune system and may play a role in preventing wound infection. However, the inherent limitations and inconsistent results of previous observational studies restricted them from inferring causal effects. We employed Mendelian randomization design to estimate the causal effects of serum 25-hydroxyvitamin D levels on the risk of post-traumatic wound infection. Data in the analysis were extracted from large-scale genome-wide association studies with 417,580 individuals for serum 25-hydroxyvitamin D measurements and 218,546 individuals for post-traumatic wound infection. Multivariable Mendelian randomization analyses were performed to adjust for confounding variables. We also conducted extensive sensitivity analyses to verify the main results. The results revealed a causal relationship between higher serum 25-hydroxyvitamin D levels and a lower post-traumatic wound infection risk (OR=0.473, p=0.014). The causality remained after adjustment of potential confounding factors according to Multivariable Mendelian randomization analyses (OR=0.361, p<0.001). Sensitivity tests suggested the reliability of our findings. This study indicated a causal association between genetically predicted high serum 25-hydroxyvitamin D levels and a decreased risk of post-traumatic wound infection.

Glucose and insulin positively regulate glycolysis and lipogenesis through the activation of carbohydrate response element-binding protein (ChREBP) and sterol regulatory element-binding protein 1c (SREBP1c), but their respective roles in the regulation of gluconeogenic and ureagenic genes remain unclear. We compared the effects of the insulin antagonist S961 and Chrebp deletion on hepatic glycolytic, lipogenic, gluconeogenic, and ureagenic gene expression in mice. S961 markedly increased the plasma glucose, insulin, and 3-OH-butyrate concentrations and reduced the hepatic triglyceride content, but Chrebp deletion had no additive effect. We subsequently estimated the expression of genes involved in the pathways of glycolysis, gluconeogenesis, and lipogenesis. S961 potently decreased both Chrebp and Srebf1c, but Chrebp deletion weakly decreased Srebf1c mRNA expression. Both the S961 and Chrebp deletion caused decreases in glycolytic (Gck and Pklr) and lipogenic (Fasn, Scd1, Me1, Spot14, Elovl6) gene expression. S961 increased the expression of many gluconeogenic genes (G6pc, Fbp1, Aldob, Slc37a4, Pck), whereas Chrebp deletion reduced the expression of gluconeogenic genes other than Pck1. Finally, we checked the metabolites and gene expression in the ureagenesis pathway. S961 increased ureagenic gene (Arg1, Asl, Ass1, Cps1, Otc) expression, which was consistent with the metabolite data: there were reductions in the concentrations of glutamate and aspartate and increases in those of citrulline, ornithine, urea, and proline. However, Chrebp deletion had no additive effect on ureagenesis. In conclusion, insulin rather than glucose regulate ureagenic gene expression, whereas glucose and insulin regulate gluconegenic gene expression in opposite directions.

Recent studies have demonstrated a significant role for gut microbiota dysbiosis in the pathogenesis of various diseases, pregnancy outcomes, and fetal growth. Vitamin D modulates innate immunity and promotes immune tolerance, suggesting involvement in shaping the gut microbiota. However, the relationship between vitamin D and the gut microbiota during pregnancy has not been evaluated in detail. In this study, we administered a vitamin D₃ supplement (VD) to pregnant Japanese women, starting during the first trimester of pregnancy, and characterized changes in the circulating concentration of vitamin D and the gut microbiome. Sixty-two pregnant women were randomly allocated to three groups. VD was administered at low (200 IU/d), medium (400 IU/d), or high (1,000 IU/d) doses for 8 wk from 12 to 15 wk of pregnancy, and changes in the serum 25-hydroxyvitamin D (25(OH)D) concentration and the gut microbiome were evaluated. Changes in gut microbial taxa abundance were analyzed by Wilcoxon matched-pairs signed-rank test. Before VD administration, 96.8% of the participants were VD-deficient, and none had a sufficient VD concentration. The serum 25(OH)D concentration increased in a dose-dependent manner in all the dose groups. Additionally, the abundance of Fusicatenibacter in the gut microbiota increased in a VD dosedependent manner, with a significant increase observed in the high-dose group. From these results, in pregnant Japanese women, the administration of high-dose VD increases the prevalence of VD sufficiency and alters the gut microbial composition, suggesting that this has benefits for the maternal and neonatal immune systems.

By comparing germ-free mice and specific pathogen-free mice, we previously demonstrated that gut commensals upregulate the expression of microRNA-200 family members, i.e., miR-200a, miR-200b, miR-200c, miR-141, and miR-429, in lamina propria leukocytes (LPLs) of the murine large intestine, and that it results in decreased production of interleukin-2, which is mainly produced by activated CD4⁺ T cells. In the present study, we investigated whether depletion of the gut microbiota by antibiotic treatment reduces the expression of miR-200 family members in T cells of the large intestinal lamina propria in mice. Supplementation of drinking water with antibiotics for 1 wk reduced the number of cecal bacteria in male C57BL/6J mice. LPLs of the large intestine were isolated and separated into T-cell and non-T-cell fractions by magnetic-activated cell sorting. Reverse transcription-quantitative polymerase chain reaction results showed that the expression levels of miR-200 family members were higher in the T-cell fraction than in the non-T-cell fraction, and were lower in the T-cell fraction of the antibiotic-treated mice than in that of the control mice. These results suggest that antibiotic-sensitive gut commensals upregulate the expression of miR-200 family members primarily in the T cells of the large intestinal lamina propria in mice.

Numerous cosmetic products claim to improve aging-induced wrinkles, and recent research has explored the potential of oral intake for wrinkle improvement. In our previous study, we investigated the effects of tomato seed extract (TSE), which contains lycoperoside H, on skin elasticity and its anti-inflammatory properties. The present study aimed to explore the anti-wrinkle effects of TSE through the inhibition of human neutrophil elastase (HNE), activated by inflammatory stimuli. The results indicated that TSE inhibits HNE (half maximal inhibitory concentration [IC₅₀]: 316 μg/mL), and that lycoperoside H contributes to this activity (IC₅₀: 37 mM). Additionally, several flavonoids found in TSE have been reported to exhibit HNE inhibitory effects. Based on these findings, we hypothesized that TSE supplementation could suppress excessive HNE activity in wrinkle-prone areas and potentially improve facial wrinkles. Therefore, we conducted a randomized, double-blind, placebo-controlled clinical trial with 45 healthy Japanese women (age range, 40-59 y) who had wrinkle grades of 3-5 around their eyes. The participants were randomly assigned to either a 200 mg/d TSE supplement (containing 1 mg of lycoperoside H) or a placebo for 12 wk. As a result, significant improvement in wrinkle grade was observed in the TSE group; however, improvements were also seen in the placebo group. Therefore, no significant differences in wrinkle reduction were found between the two groups. These findings suggest that the inhibition of HNE by TSE may have potential effects on the dermis, thereby offering new insights into the role of TSE in skin health.

Only approximately 30% of ingested zinc (Zn) is absorbed. Some foods consumed with Zn affect its intestinal absorption. Zn supplementation is generally recommended immediately after meals to minimize gastric irritation. In this study, we examined the effects of food intake on Zn absorption. Zn acetate (25 mg as zinc) was administered orally to 13 healthy young volunteers either in the fasting state or with foods, such as 150 g of brown rice, white rice, beef hamburg, 200 mL of miso soup (fermented soybean paste soup), seaweed soup, cow's milk, Japanese tea and orange juice (100% fruit juice). Blood samples were collected before and at 1, 2, 3, and 4 h after administration of Zn alone, food alone (without Zn), or food with Zn. Zn absorption was compared using the area under the curve. The results showed that serum Zn levels hardly increased when Zn was administered with brown rice, whereas the Zn level was not inhibited by coadministration with seaweed soup. The absorption of Zn acetate with other foods was reduced to 14-66% compared to that when Zn was administered alone. Our results suggest that brown rice, which is a popular food in Japan and other countries, is associated with decreased Zn absorption.

Nutritional environments in the early life shape the development of neural systems involved in rewards. While the effects of maternal nutritional status on offspring feeding behavior have been studied, the impact of non-nutrient dietary components remains poorly understood. We previously reported that prenatal exposure to bonito broth (katsuo-dashi) reduces the motivation of adult offspring to consume fat. In the present study, we explored the potential molecular mechanisms underlying this phenomenon. First, we confirmed that bonito broth intake during gestation did not affect maternal nutrition or body weight, ruling out maternal undernutrition as a confounding factor for the offspring phenotype. Using fiber photometry, we determined that corn oil intake increased dopamine release in the nucleus accumbens (NAc), but the response did not correlate with motivational behavior. In control offspring, the mRNA expression of genes related to dopamine (Drd1), opioid (Oprm1, Oprk1), glutamate (Grin1), and GABA (Gabra1) signaling was upregulated in the NAc after exposure to corn oil, and the response was significantly attenuated in the gestation group. These changes in gene expression were not observed in the ventral tegmental area or in the amygdala. These findings suggest that prenatal exposure to bonito broth through the mother attenuates transcriptional responses to dietary fat in reward-related brain regions, particularly the NAc, without affecting dopamine dynamics or maternal nutrition.

Maintenance of appropriate muscle mass is necessary for good quality of life as skeletal muscles play critical roles in locomotion, metabolic homeostasis, and thermogenesis. Polyamines are essential metabolites that regulate several important cellular functions. In C57BL6 mice who underwent sciatic nerve transection of the hind limb, compensatory muscle hypertrophy is enhanced by the administration of polyamines. However, the action mechanisms of polyamines in muscle hypertrophy remain unclear. Here, we isolated PA YEAST SC-1, a polyamine-rich Saccharomyces cerevisiae, from Baker's yeast. We examined whether PA YEAST SC-1 induces muscle hypertrophy and elucidated the underlying action mechanisms of polyamines and the active ingredients in PA YEAST SC-1 using C2C12 myotubes. PA YEAST SC-1 at 1 mg/mL increased myosin heavy chain expression in C2C12 myotubes. Mechanistically, PA YEAST SC-1 induced the activation of Akt/mechanistic target of rapamycin kinase/p70S6K signaling. Furthermore, PA YEAST SC-1 decreased the expression levels of the ubiquitin ligases, atrogin-1 and muscle RING finger-1, via forkhead box O1 phosphorylation. These findings suggest PA YEAST SC-1 as an effective food ingredient for the treatment of muscle hypertrophy.