Journal of nutritional science and vitaminology最新文献

Blood ascorbic acid (AsA) concentrations are lower in diabetic patients than in the general population, a phenomenon that is also observed in streptozotocin (STZ)-diabetic models of type 1 diabetes. However, the occurrence of diabetes in KK-Ay mice, a model for type 2 diabetes, the most common form of diabetes, remains unclear. Although this mouse can synthesize AsA, understanding its level changes during diabetes progression could help in analyzing AsA's effects on type 2 diabetes. Therefore, the present study investigated the relationship between hyperglycemia and AsA concentrations in the blood and organs of KK-Ay mice, and discussed the findings in relation to those observed in STZ-diabetic mice. Male KK-Ay mice were examined at different stages of diabetes (pre-diabetic, early onset, and hyperglycemic maintenance). STZ-diabetic mice were generated by administering STZ to ICR mice. AsA concentrations were measured in plasma, blood mononuclear cells, and tissues, along with hepatic L-gulonolactone oxidase (GLO) activity and mRNA expression levels. Unexpectedly, AsA concentrations in KK-Ay mice increased under hyperglycemic conditions, while they decreased in STZ-diabetic mice. A consistent relationship was not observed between organ AsA concentrations and hyperglycemia. GLO activity and mRNA expression levels increased in KK-Ay mice, but decreased in STZ-diabetic mice, suggesting an innate defense mechanism against hyperglycemia in KK-Ay mice. These results indicate that different diabetes models exhibit distinct changes in AsA concentrations and hepatic GLO activity under hyperglycemic conditions, highlighting the importance of considering endogenous AsA when evaluating the antioxidant properties of dietary components in KK-Ay mice.

Non-alcoholic fatty liver disease (NAFLD) is influenced by various factors including diet, genetic predisposition, adipocytokines, oxidative stress and endoplasmic reticulum (ER) stress. In this study, we examined how pre-feeding mice a high-fat diet rich in saturated fatty acids (SFAs) affected various indicators of liver disease after administering tunicamycin (TM), an ER stress inducer. We used 4-wk-old male C57BL/6J mice, dividing them into four groups: a normal diet (C), a high-fat diet (F), a normal diet with TM (CT), and a high-fat diet with TM (FT). After 8 wk of feeding, we administered TM intraperitoneally to the CT and FT groups, followed by an anatomical examination 24 h later. TM administration led to increased triglyceride (TG) and cholesterol accumulation in the liver, while significantly lowering TG, cholesterol, and ApoB levels in the plasma. Although liver TG levels were higher in the CT group compared to the FT group, large lipid droplets were present in all individuals only in the FT group. Classic non-alcoholic steatohepatitis markers, such as neutrophil infiltration and hepatocyte ballooning, were not observed. Additionally, plasma alanine aminotransferase activity and expression levels of ER stress-related proteins were significantly higher in the FT group than in the CT or F groups. These findings indicate that combining a high-fat diet rich in SFAs with TM exacerbates ER stress-induced fatty liver disease. This model may be a valuable tool for preclinical trials aimed at addressing ER stress in early-stage NAFLD.

Acute arterial stiffening occurs during postprandial hyperglycemia. Such vascular responses are suggested to be averted by suppressing the postprandial glycemic response. We previously developed an α-glucosidase-inhibiting tea powder from the leaves of Morus australis (M. australis), a mulberry species distributed in the Ryukyu Islands, and demonstrated that this powder has an inhibitory effect on blood glucose elevation after sucrose ingestion. This study aimed to investigate the effect of powdered M. australis leaf intake on the arterial stiffness response after sucrose ingestion. In a randomized crossover design, 12 healthy young men completed two trials: with (mulberry [M] trial) and without (control [C] trial) intake of powdered M. australis leaves before ingestion of 75 g of sucrose. Blood glucose levels and brachial-ankle pulse wave velocity (baPWV), an index of systemic arterial stiffness, were measured at baseline and 30, 60, and 120 min after ingestion. Both trials caused a significant increase in blood glucose levels at 30 and 60 min after ingestion, with significantly lower values at 30 min after ingestion in the M trial than in the C trial. baPWV significantly increased at 60 min after ingestion in the C trial, but not in the M trial. These findings demonstrate that prior ingestion of powdered M. australis leaves can prevent the transient arterial stiffening after sucrose ingestion in healthy young men.

Skipping breakfast is observed in approximately 30% of youth. Since gastric motility is involved in morning appetite, we conducted a 2-wk nutrition education program for high school dormitory students to encourage breakfast consumption and examined whether gastric myoelectrical activity before breakfast was improved. Gastric motility was assessed by measuring the dominant frequency (DF), derived from power spectrum analysis of normal waves occurring approximately three times per minute, and the percentage (%) normal power. Participants were divided into a normal-gastric motility group (Normal-GM, DF ≥ 2.5 cpm, % normal power ≥50%, n=10) and a low-gastric motility group (Low-GM, DF<2.5 cpm, % normal power <50%, n=7) based on the morning gastric motility index. Nutrition education (i.e. the intervention) was provided to all participants and the same measurements were taken 2 wk later. The results showed an improvement in DF in the Low-GM group (1.99±0.09 cpm to 2.90±0.22 cpm, p=0.008) after the intervention. In addition, % normal power increased significantly only in the Low-GM group (42.9±2.6% to 54.2±2.9%, p=0.047). These results suggest that regular breakfast consumption may help normalize lower morning gastric motility in high school students.

Nutritional guidance typically uses protein and lipid intake rather than amino acids and fatty acids. However, the composition of amino acids and fatty acids varies depending on the food source, requiring detailed analysis for accurate dietary assessment. Currently, limited research exists on the detailed composition of foods commonly consumed in Japan. Therefore, we aimed to compare the characteristics of amino acid and fatty acid in foods that are the major sources of protein in the Japanese diet. Data cleaning was performed on 2,478 foods listed in the Food Composition Table 2020 (8th revision). Heatmap cluster analysis was performed for food groups, amino acid, and fatty acid, and statistical analysis was performed to determine the percentage differences between food groups. Heat map cluster analysis of the fish and meat data showed that the foods were divided into two groups in the first level (fish and meat). Characteristic amino acid and fatty acid were 5/8 for meat, 1/27 for fish, and 13/0 for common, and no common fatty acid were noted. Significant differences were found between nine amino acids and 31 fatty acids. Heat map cluster analysis using data on seafood, meat, legumes, and eggs showed that foods could be classified into two clusters at the first level: seafood and meat, with legumes and eggs included in the meat cluster. The results of the heat map cluster analysis using statistical analysis and means indicated that seafood, meat, and legumes were characterized differently, especially in terms of fatty acid.

This study investigated the cross-sectional association between major dietary patterns and premenstrual syndrome (PMS). Participants were 427 women aged 22-50 y who responded to a mail survey in 2022-2023. Dietary patterns were derived using principal component analysis based on consumption of 52 food and beverage items ascertained by a validated self-administered diet history questionnaire. PMS were assessed using the Premenstrual Symptoms Questionnaire. Logistic regression analysis was used to estimate odds ratios of PMS according to tertiles of dietary pattern scores. The prevalence of moderate to severe PMS was 9.6% (41 women). We identified four dietary patterns: vegetable, tomato and fish, Japanese, and alcohol dietary patterns. No dietary pattern was significantly associated with PMS. However, the odds ratios of PMS in the highest tertile of the vegetable dietary pattern (characterized by high intake of vegetables, mushrooms, potatoes, seaweeds, and chicken) tended to be lower compared to the lowest tertile. The multivariable-adjusted odds ratio of PMS for the highest versus lowest tertile of the vegetable dietary pattern score was 0.69 (95% confidence interval 0.30-1.59). None of the dietary patterns were appreciably associated with PMS. The finding of lower odds of PMS among women with a high score for the vegetable dietary pattern deserves further investigation.

To clarify the association between the intake frequency of a meal combination of staple, main, and side dishes (SMS meal), determined using a validated questionnaire, and the intake of various nutrients and food groups among Japanese adults. In this cross-sectional study, we analyzed data from 936 persons aged 18-64 y who participated in the Dynamics of Lifestyle and Neighborhood Community on Health Study. The intake frequency of SMS meals was assessed using our validated questionnaire and validated. The intake of nutrients and food groups was examined using validated food-frequency questionnaires. To examine the association of the intake frequency of SMS meals with the intake of specific nutrients and food groups, linear regression analysis was conducted with adjustment for age, body mass index, education history, living status (alone or not), smoking status, and alcohol drinking. The intake frequency of SMS meals was significantly positively associated with the intake of 24/32 nutrients in men, 8/32 nutrients in women, 6/16 food groups in men, and 1/16 food groups in women, and significantly negatively associated with 2/16 food groups in men. A higher intake frequency of SMS meals was not significantly associated with a higher intake of salt or saturated fats. Our results suggest that a higher intake frequency of SMS meals, examined using a validated questionnaire, may be associated with a higher intake of certain nutrients and food groups among young and middle-aged adults without a higher intake of salt and saturated fats.

Academic performance, assessed through tests and assignments, significantly influences long-term outcomes, such as employment, income, and quality of life. Several recent studies have indicated a relationship between skipping breakfast and academic performance; however, no meta-analysis has been performed to explore this association. In the present study, we conducted a meta-analysis of observational studies to synthesize the association between skipping breakfast and academic performance in youths. We perused the literature published before October 2024 using PubMed, Science Direct, Springer Link, and Scopus. We calculated a pooled odds ratio (OR) with 95% confidence interval (95% CI) using a random effects model. The study quality was assessed using the Newcastle-Ottawa Scale adapted for cross-sectional studies. With regard the quality of the included studies, two articles were considered unsatisfactory, five as satisfactory, sixteen as good, and two as very good. After screening, 24 observational studies with 37 reports were included in the meta-analysis. A positive association was observed between skipping breakfast and the risk of poor academic performance (pooled OR=2.08, 95% CI=1.82-2.37). Subgroup analyses based on gender, region, sample size, assessment tools, definition of outcomes, and confounding variables also revealed that skipping breakfast is positively correlated with poor academic performance in youths. In conclusion, this meta-analysis indicates that skipping breakfast is positively associated with poor academic performance in youths.

The global increase in hyperuricemia, a pathological condition characterized by elevated serum urate concentrations, emphasizes the importance of appropriate management of uric acid homeostasis in the body. Enhancing renal urate excretion is clinically relevant to achieve serum urate-lowering, and the functional inhibition of urate transporter 1 (URAT1), a renal urate transporter involved in the reabsorption of urate, has been recognized as a promising strategy. In this context, natural substances, including food ingredients with URAT1-inhibitory activity, have garnered significant interest. A previous study demonstrated that various fatty acids, including α-linolenic acid (α-LA), inhibit URAT1; however, further investigations are required to expand our understanding for this important topic. The present study focused on certain metabolites derived from α-LA, especially jasmonates (lipid-derived cyclopentanone compounds in plants) and related substances, and investigated their effects on URAT1-mediated urate transport activity, using a mammalian cell-based functional assay system. Among the tested substances (14 authentic chemicals), 12-oxo-phytodienoic acid (a precursor of jasmonic acid harboring a cyclopentenone ring with two carbon chains in its structure) showed a good URAT1-inhibitory activity with the half maximal inhibitory concentration (IC₅₀) value of 15.9 μM. Comparable results were obtained with prostaglandin A₁ (PGA₁) and PGA₂, which are known as cyclopentenone PGs, that exhibited IC₅₀ values of 22.5 μM and 16.8 μM, respectively. Although further studies are required to address the effects of these substances on the urate regulation in humans, our findings contribute to a deeper understanding of the interactions between URAT1 and natural substances.

Rhizopus oligosporus (R. oligosporus) is a fungus belonging to the Mucoraceae and is usually used to ferment soybeans in East Asia. R. oligosporus-fermented soybeans are called tempeh and are mainly eaten in East Asia. The recent researches have demonstrated that R. oligosporus can also ferment the beans other than soybeans. In this study, raw coffee beans were fermented with R. oligosporus, and then the effects of coffee prepared from the fermented beans were investigated. The amounts of fats and saccharides were lower in the R. oligosporus-fermented coffee beans than in the unfermented coffee beans, but the amount of dietary fiber was increased in the fermented coffee beans. The R. oligosporus-fermented coffee exhibited decreased total polyphenol levels, and its antioxidant activity was also reduced. However, the concentration of chlorogenic acid, which is one of polyphenols, in the R. oligosporus-fermented coffee was higher than that in the unfermented coffee. In comparison to the unfermented coffee, the R. oligosporus-fermented coffee inhibited α-amylase and α-glucosidase activity more strongly, inhibited cancer growth more weakly or to a similar level, and inhibited H₂O₂-induced reactive oxygen species production more weakly. The inhibition of α-amylase and α-glycosidase activity is considered to contribute to the prevention of obesity and diabetes. Fermenting raw coffee beans with R. oligosporus may contribute to improving certain effects of coffee, especially the preventative effects against obesity and diabetes.