Mental stress is a known risk factor for lifestyle-related diseases. Previously, we reported that short-term stress sharpens the sense of taste and dulls the sense of pungency, but in this study, we examined the effects of chronic mental stress on taste and pungency by comparing normal days with end-of-semester examination days. Furthermore, the relationship between pungency measured on the tongue and the corresponding skin current value causing forearm pain was investigated. Taste and pungency were blindly measured using the filter paper disc method on a normal day and the day before the end-of-semester examination (chronic mental stress day) in 27 healthy male university students. A commercially available taste liquid for taste testing and a capsaicin solution for pungency were used. Taste perception was also tested using cognitive thresholds, and pungency was tested using a unified concentration and maximum tolerated threshold concentration. With a PainVision^® device, currents were gradually increased in forearm skin to quantify the sensation of pain. Stress levels were measured with electrocardiography and a questionnaire. The median cognitive threshold for taste (salty, sweet, sour, and bitter) was slightly dulled due to chronic mental stress on the day before examination day and was duller than that on the normal day, but the difference was not significant. Pungency and forearm skin pain were significantly dulled on the day before examination day, and pungency correlated significantly with forearm skin pain. Chronic mental stress appeared to dull especially the sensitivity to pungency and skin pain.

Combinations of cysteine, ascorbic acid, and pyridoxine are frequently used in oral formulations. Although there have been many reports on the efficacy of each of these ingredients, little information is known about their combined effects on skin cells. The purpose of this study was to evaluate the combined effects of cysteine, ascorbic acid, and pyridoxine, as well as the effect of adding α-lipoic acid, on skin cells. Human keratinocytes were treated with individual antioxidants or combinations of them, and glutathione levels and expression of glutathione synthesis-related genes were measured. The combination of cysteine, ascorbic acid, and pyridoxine increased the expression of γ-GCSc and tended to increase glutathione levels compared to the controls. Interestingly, the addition of α-lipoic acid further increased glutathione levels by increasing the expression of CD98. Similarly, in 3D-human skin models, the combination of cysteine, ascorbic acid, and pyridoxine promoted glutathione synthesis, and this effect was enhanced by the addition of α-lipoic acid. Furthermore, melanin synthesis inhibition was shown to be dependent on increased glutathione levels. These results suggest that the addition of α-lipoic acid to the combination of cysteine, ascorbic acid, and pyridoxine enhances glutathione production and may have anti-aging effects through efficient oxidative stress reduction.

The nutritional status of fathers plays a significant role in influencing the growth, metabolism, and susceptibility to diseases in their offspring. Paternal zinc deficiency can lead to developmental programming effects on the offspring’s zinc homeostasis. This study investigated the effects of paternal zinc deficiency on the zinc homeostasis of offspring in a Drosophila melanogaster (fruit fly) model. Male flies were reared on a diet supplemented with a zinc-chelator, N,N,N′,N′-Tetrakis(2-pyridylmethyl)ethylenediamine (TPEN), from the egg stage until adulthood, and their offspring were subsequently reared on a normal diet for 7 d. Body zinc status and zinc transporters were assessed afterwards. The results indicated that the prenatal zinc deficiency significantly lowered total body zinc levels (p<0.05) compared to the controls. Additionally, the mRNA levels of zinc transporters, dZip42C.1, dZnT63C, and dZnT35C, were lower in the zinc-deficient male parents (p<0.05) and their male offspring (p<0.05). These findings suggested that paternal zinc deficiency can alter offspring zinc homeostasis, even when the offspring was fed a zinc-sufficient diet. This is an important finding, as zinc is an essential nutrient that is required for a variety of bodily functions. Further research is needed to better understand the mechanisms by which zinc deficiency in the male parent affects the health of the offspring and to develop strategies to prevent this from happening.

The diet consumed by most Japanese people, which contains high amounts of carbohydrate and low levels of fat compared with the Western-style diet (WD), has been considered an effective diet for promoting glycogen recovery after exercise. However, there is no direct evidence to support this general belief, because no studies have examined the effect of whole, actually cooked Japanese-style diet (JD) on post-exercise glycogen replenishment. In this study, we comparatively examined the effects of a cooked typical JD and WD on glycogen accumulation in mouse skeletal muscle and liver after acute exercise. One-week menus (total 21 meals) of the JD and WD were reproduced based on national nutrition surveys in Japan and the U.S. All the meals were cooked, mixed and then fed to mice after acute 60-min running exercise. After the 4-h recovery period, mice given the JD had significantly higher muscle and liver glycogen concentrations than those fed the isoenergetic WD. Furthermore, even after the 24-h recovery period, the JD-fed mice also had significantly higher muscle glycogen concentration than the isoenergetic WD-fed group. Compared with the mice fed a WD, the JD-fed mice showed significantly higher plasma insulin level during the 4-h but not the 24-h recovery period. These results suggest that both short- and long-term feeding of the JD promote post-exercise muscle glycogen recovery compared to the WD, possibly through an insulin-dependent mechanism and non-insulin-dependent mechanism, respectively.

Recently, we demonstrated, using mRNA microarray analysis, that fructo-oligosaccharides (FOS), which are indigestible carbohydrates, enhanced the expression of several inflammation-related genes, such as CLEC7A, CCL2, ITGA2, and F3, by ≥4-fold in Caco-2 cells, a model of human intestinal absorptive cells, independently of intestinal bacteria (Harasawa A et al., Nutrition, 112140, 2023). However, whether FOS enhances the expression of genes in other pathways, particularly the non-inflammatory pathways, in Caco-2 cells has not been investigated. Here, we explored the pathways affected by FOS, based on identification of differentially expressed genes with ≥2-fold change (linear-fold change) in expression upon FOS treatment. Caco-2 cells were cultured for 24 h in high glucose-Dulbecco’s modified Eagle medium supplemented with 10% fetal calf serum containing FOS. The differentially expressed genes in these cells, identified using mRNA microarray analysis, were categorized using the pathway analysis and subsequently upregulated genes in typical pathways were subjected to protein network analysis. RT-qPCR was performed to validate the expression of selected genes. Treatment with 10% FOS enhanced the expression of a set of genes, such as ITGB8, ITGA6, SPP1, CAV1, LAMA3, ARHGAP5, and LAMC2, in the focal adhesion pathway. In addition, this treatment increased the expression of many genes involved in various inflammatory pathways, such as TNF, ITGA5, ITGB3, PTGS2, FGF2, FLNC, EDNRB, VEGFA, and MMP13. Protein network analysis showed that genes in the focal adhesion and endothelin pathways induced by FOS were closely associated with each other. FOS treatment of human intestinal absorptive-like cells enhances a set of genes in the focal adhesion and inflammation pathways.

Carbohydrate-rich solid foods, such as bread, pasta, and steamed rice, are applied for test meals in studies examining digestion and absorption of food related to glucose metabolism and sports science. Such research must consider that drinking water is sometimes better as it avoids the risk of choking or aspiration. However, the water increases test meal volume and dilutes glucose concentration, which may influence the digestion and absorption of ingested foods, as well as energy metabolism. Therefore, this study aimed to investigate whether the peak time and concentration of glucose and energy metabolism will differ among the intake of steamed rice alone (Rice), simultaneous intake of steamed rice and water (Mixed), and water alone (Water). Following the intake of the test meals, there was an immediate increase in blood glucose in Mixed compared to Rice and Water. The glucose peak time of Rice (60 (56–68) min; median and quartile) was also delayed compared to Mixed (38 (29–45) min). The blood lactate peak time was also significantly different in Mixed and Rice. Although meal and time interaction was not found in energy expenditure, Mixed increases the respiratory quotient by 40 min compared to Water. In conclusion, this study demonstrated that simultaneous intake of steamed rice and water hasted digestion and absorption of glucose and activates glycolysis. Future studies investigating gastric emptying rate and glucose metabolism should ensure that the conditions of fluid intake and the test meal volumes are consistent and do not differ significantly.

This study aimed to investigate the regulatory effects of raspberry ketone on hypothalamic inflammation and its mechanism. Mouse microglia cells (BV2 cells) were cultured in vitro with palmitic acid (100 μM) to induce inflammation model and then incubated with raspberry ketone (5, 20, 50 μM) alone or raspberry ketone (50 μM) and the specific inhibitor of uncoupling protein 2 (UCP2), genipin (10 μM), to test the role of UCP2 in raspberry ketone regulatory of inflammation. Meanwhile, C57BL/6J mice were fed a high-fat diet containing raspberry ketone (0.2%, wt/wt) for 16 wk or 7 d to observe the effects of raspberry ketone on the body weights and hypothalamic inflammation of mice. The expression levels of inflammatory factors, including interleukin-6 (IL-6), interleukin-1beta (IL-1β) and tumour necrosis factor alpha (TNF-α), were detected using RT-qPCR, Elisa, and Western blotting, respectively. At the cellular level, raspberry ketone reduced the content of inflammatory factors in BV2 cells and in the cell culture medium. Genipin inhibited the anti-inflammatory effect of raspberry ketone on BV2 cells. At the animal level, after 16 wk of feeding, raspberry ketone-containing diets significantly reduced the body weight of mice, but had no significant effect on the mRNA expression level of hypothalamic inflammatory factors. On the other hand, 7 d of raspberry ketone gavage significantly reduced mRNA and protein expression of hypothalamic inflammatory factors. The results of this study suggest that raspberry ketone could regulate high-fat diet-induced obesity in mice, and the specific mechanism may be to inhibit hypothalamic inflammation in mice by regulating UCP2 gene expression.

The Forsythia has been used in herbal medicine, and the leaf is also expected to contain various putative bioactive substances. In this study, we investigated the effects of Forsythia viridissima leaf extract (FLE) on bone metabolism. The anti-osteoporotic effect of FLE was determined in male rats fed a low-calcium diet. Micro-CT analysis of the distal end of the left femur showed a trend toward less reduction in total bone mineral density (total BMD) in the group received FLE on a 0.05% low-calcium diet compared to the low-calcium control group. Also, trabecular bone mineral density (Tb.BMD) was significantly less decreased in the FLE group. Then, in vitro experiment, we found that matairesinol, a lignan particularly rich in Forsythia leaf, remarkably promotes osteoblastic mineralization. Thus, our study revealed that FLE inhibits the progression of osteoporosis caused by calcium deficiency.

Whole-body vibration (WBV) has gained attention as a light-resistance exercise and can increase energy metabolism. The rare sugar D-allulose has anti-obesity effects that are mediated by the suppression of hepatic lipogenesis. In this study, we examined the anti-obesity effects of a combination of WBV and dietary D-allulose in rats fed a high-fat diet. Thirty-two male Wistar rats (3-wk-old) were randomly assigned to four groups: sedentary control (C), WBV (V), D-allulose (A), and WBV+D-allulose (VA). Rats in Groups A and VA were fed a 5% D-allulose diet, and rats in Groups V and VA were subjected to WBV using a vibrating platform during the 8-wk experimental period. Total abdominal adipose tissue was significantly lower in Groups V, A, and VA than that in Group C, whereas no differences were observed between Groups V, A, and VA. Dietary D-allulose significantly decreased the weights and percentages of carcass and total body fats, whereas the WBV stimulus significant reduced only the total body fat mass. We observed that both long-term WBV stimulation and dietary D-allulose intake inhibited body fat accumulation in rats fed a high-fat diet, which led to obesity; however, no synergistic effect of this combination could be confirmed.

Black rice (BR) is beneficial for the health of animals and humans. Herein, we investigated the pharmacokinetics of cyanidin-3-glucoside (C3G), a major anthocyanin constituent of BR, in male rats. After its intravenous administration, C3G was rapidly distributed throughout the body and disappeared from the plasma. Its cumulative urinary excretion accounted for less than 20% of the dose administered. After a single dose of BR extract (C3G40) containing C3G was orally administered (300 mg C3G/kg body weight), the C3G plasma concentration peaked at 30 min and then rapidly declined within 4 h. The extent of the cumulative urinary excretion of C3G, together with the area under the curve (AUC) of the plasma C3G concentration, indicated a bioavailability of approximately 0.5–1.5%. These results suggest that C3G was rapidly absorbed from the gastrointestinal tract in rats; however, its plasma concentration was very low. We also examined the enhancing effect of allyl isothiocyanate (AITC), a pungent component of wasabi, on the gastrointestinal absorption of C3G in rats. Following the co-administration of C3G with AITC dissolved in PEG200, the urinary excretion and AUC of C3G were 4.5- and 2.7-fold higher than those in the control group (without AITC) (p<0.01), respectively. This is the first study to show that the gastrointestinal absorption of BR anthocyanins is promoted by AITC.