Journal of nutritional science and vitaminology最新文献

Niacin is involved in many biological reactions relating energy metabolism, redox reactions, DNA repair and longevity. Since niacin deficiency has been reported in alcoholic patients, and niacin coenzyme NAD is used as substrate to dehydrogenate ethanol in the liver, ethanol consumption can be a factor to impair niacin nutritional status. We have recently established the niacin insufficient model mice using kynurenine 3-monooxygenase knock out (KMO^-/-) mice with niacin-limited diet, which lack the de novo NAD synthesis pathway from tryptophan. To evaluate the effects of chronic ethanol intake on niacin nutritional status, 4 wk old KMO^-/- mice were fed 4 or 30 mg/kg nicotinic acid containing diets with or without 15% ethanol for 35 d. The mice fed 4 mg/kg nicotinic acid diet with ethanol showed lower body weight gain and niacin nutritional markers such as liver and blood NAD, and urine nicotinamide metabolites than the mice without ethanol. These animals did not show any difference in the NAD synthesis, NAD salvage and nicotinamide catabolic pathways. Chronic ethanol intake failed to affect any indices in the mice fed the 30 mg/kg nicotinic acid diet. When the diet was exchanged the 4 mg/kg for 30 mg/kg nicotinic acid diet to the mice showed chronic ethanol-induced growth retardation, their body weight rapidly increased. These results show that chronic ethanol intake impairs niacin nutritional status in the niacin insufficient mice, and enough niacin intake can prevent this impairment. Our findings also suggest that chronic ethanol intake increases niacin requirement by increase of NAD consumption.

Nutritional disorders in patients with chronic obstructive pulmonary disease (COPD) are associated with cachexia, sarcopenia, and weight loss. In particular, weight loss is a prognostic factor in COPD independent of pulmonary function, and energy malnutrition is a contributing factor. Frequent exacerbation hospitalization is also a prognostic factor for COPD patients. The impact of energy malnutrition on adverse events such as exacerbation hospitalization is unknown, and this study aimed to investigate that. We included 163 male subjects with COPD. Respiratory quotient (RQ), an index of energy malnutrition, was calculated by expiratory gas analysis using an indirect calorimeter. RQ <0.85 was categorized as the energy malnutrition group. Kaplan-Meier analysis was used to compare the hospitalization avoidance rate between the with and without energy malnutrition groups. Independent factors associated with exacerbation hospitalization were evaluated by Cox regression analysis. We finally analyzed data from 56 selected subjects (median age: 74 y). The exacerbation hospitalization rate was significantly higher in the energy malnutrition group. Fifty percent of the energy malnutrition group was hospitalized for an exacerbation, and the median hospitalization avoidance time was 701 d. In Cox regression analysis (adjusted for age, BMI, mMRC dyspnea scale score, %FEV₁, and 6-min walk test), energy malnutrition was an independent factor associated with exacerbation hospitalization (HR 4.14, 95% CI 1.13-15.1, p=0.03). Energy malnutrition may be the risk factor for exacerbation hospitalization. Energy malnutrition may be an early nutritional disorder and early detection and intervention may reduce exacerbation hospitalizations.

L-Theanine is contained in green tea at 1-3% per dry matter as an amino acid with an umami taste, and the antidepressant effect and protective effect against stress-induced brain atrophy in mice, as well as the related mechanism have been reported. However, effects of theanine on the hippocampus from the proteome analysis and the action mechanism have not been examined. In this study, we mainly investigated the possibility of theanine's cognitive impairment-preventing function and the action mechanism by proteomics in the hippocampus of SAMP8 administered with theanine. In addition to improvement in the aging score with theanine administration, in proteomics, significant suppressions in the expressions of synapsin 2, α-synuclein, β-synuclein, and protein tau were observed by theanine administration, and the expression of CAM kinase II beta and alpha exhibited a significant increase and increasing tendency with theanine administration, respectively. The expression of tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein tended to increase by theanine administration. On the other hand, serotonin/tryptophan, GABA/glutamic acid and glutamine/glutamic acid ratios in the hippocampus showed an increasing tendency, a significant increase, and an increasing tendency with theanine administration, respectively. These results suggested that theanine might have been involved in the improvement of neurodegeneration or cognitive impairment by suppressing the productions of synapsin, synuclein and protein tau which are considered to be produced along with aging and oxidation, and by enhancing the production of serotonin by increasing the expression of CAM kinase II, and further by affecting the metabolism of glutamate.

Fibroblast growth factor-23 (FGF23) is a phosphaturic hormone secreted by osteocytes in response to dietary phosphate intake. An increase in FGF23 level is an indicator of excess phosphate intake relative to the residual nephron number. Therefore, avoiding excessive phosphate intake and inhibiting the elevation of serum FGF23 levels are important to preserve the number of functional nephrons. This randomized crossover trial aimed to determine the potential differences in the impacts on serum FGF23 levels between plant protein and animal protein-based meals in individuals with normal renal function. Nine young men were administered plant (no animal protein) or animal protein-based meals (70% of their protein was from animal sources) with the same phosphate content. The test meals consisted of breakfast, lunch, and dinner. Blood samples were collected in the morning, after overnight fasting, and before and after eating the test meals (for two consecutive days at the same hour each day). Furthermore, a 24-h urine sample was obtained on the day the test meal was consumed. No significant interactions were found among serum phosphate, calcium, and 1,25-dihydroxyvitamin D levels. However, after eating plant protein-based meals, serum FGF23 levels decreased and serum intact parathyroid hormone levels increased (interaction, p<0.05). Additionally, urine 24-h phosphate excretion tended to be lower in individuals consuming plant protein-based meals than in those consuming animal protein-based meals (p=0.06). In individuals with normal renal function, plant protein-based meals may prevent an increase in serum FGF23 levels and kidney damage caused by phosphate loading.

Evaluating the autonomic nervous system (ANS) via heart rate variability (HRV) to investigate the effects of food on human health has attracted attention. However, using a conventional HRV analysis via the fast Fourier transform (FFT), it is difficult to remove artifacts such as body movements and/or abnormal physiological responses (unexpected events) from the HRV analysis results. In this study, an analysis combining bandpass filters and the Hilbert transform was applied to HRV data on functional food intake to compare with FFT analysis. HRV data were obtained from six males by recording electrocardiograms on functional food, γ-aminobutyric acid, intake. HRV indices were calculated by both analysis. In the Hilbert analysis, all HRV indices were obtained for the same number of sampling points as the HRV data. The standard errors of all HRV indices tended to be smaller in the Hilbert analysis than in the FFT analysis. In conclusion, the Hilbert analysis was more suitable than FFT analysis for evaluating ANS via HRV on functional foods intake.

Cellular NAD⁺ is continuously degraded and synthesized under resting conditions. In mammals, NAD⁺ synthesis is primarily initiated from nicotinamide (Nam) by Nam phosphoribosyltransferase, whereas poly(ADP-ribose) polymerase 1 (PARP1) and 2 (PARP2), sirtuin1 (SIRT1), CD38, and sterile alpha and TIR motif containing 1 (SARM1) are involved in NAD⁺ breakdown. Using flux analysis with ²H-labeled Nam, we found that when mammalian cells were cultured in the absence of Nam, cellular NAD⁺ levels were maintained and NAD⁺ breakdown was completely suppressed. In the presence of Nam, the rate of NAD⁺ breakdown (R_B) did not significantly change upon PARP1, PARP2, SIRT1, or SARM1 deletion, whereas stable expression of CD38 did not increase R_B. However, R_B in PARP1-deleted cells was much higher compared with that in wild-type cells, in which PARP1 activity was blocked with a selective inhibitor. In contrast, R_B in CD38-overexpressing cells in the presence of a specific CD38 inhibitor was much lower compared with that in control cells. The results indicate that PARP1 deletion upregulates the activity of other NADases, whereas CD38 expression downregulates the activity of endogenous NADases, including PARP1 and PARP2. The rate of cellular NAD⁺ breakdown and the resulting NAD⁺ concentration may be maintained at a constant level, despite changes in the NAD⁺-degrading enzyme expression, through the compensatory regulation of NADase activity.

Dietary Reference Intakes for Japanese provide target values for proteins, fats, and carbohydrates. However, they do not provide information on reference values for amino acids (AAs) and fatty acids (FAs), which determine the quality of foods in detail. Therefore, we evaluated AAs and FAs using the Food Exchange Lists-Dietary Guidance for Persons with Diabetes (in Japanese) Utilization, Second Edition Sample Menus and Practice (FELD) as an ideal Japanese diet. Based on FELD, 15 different daily meal patterns were employed with combinations of three levels of carbohydrates %energy (high carbohydrate [HC], 60%; middle carbohydrate [MC], 55%; and low carbohydrate [LC], 50%) and five levels of energy (1,200-2,000 kcal). Using the Japanese Food Composition Table 2020 adjusted for 1,000 kcal, 18 AAs, 49 FAs, and calorie densities (CDs, kcal/g) were calculated and compared among the three groups. Dietary AA was rich in glutamic acid, aspartic acid, and leucine; in order, no significant differences were observed among HC, MC, and LC for 18 AAs. Dietary FA was higher for 18:1 total, 16:0, and 18:2 n-6. Moreover, 16:0, 20:0, and 18:1 total in LC and 22:0 and 18:3 n-3 in MC were significantly higher than those in HC. The HC, MC, and LC CD was low at 0.82, 0.84, and 0.93 kcal/g, respectively. No significant differences in 18 AAs and CD were noted among HC, MC, and LC in FELD; however, significant differences were observed in the FA profiles. This study suggests the importance of evaluating diet using AA and FA units.

The Ussing chamber is a tool for analyzing drug absorption. We investigated whether the Ussing chamber can be used to analyze the process from digestion to absorption of protein in the gastrointestinal tract. Mixtures containing infant formula, whole cow's milk, processed soy milk, enteral nutrition, or human breast milk, were placed in the apical membrane side equipped with Caco-2 cells. After the addition of first pepsin then pancreatin, samples from the apical and basal membranes were collected. Infant formula showed the highest digestibility and absorption rate. This may be attributed to the presence of whey protein, which is rapidly digested and absorbed. The digestion and absorption of human breast milk showed different results in each donor, suggesting that digestion and absorption may vary among individuals. We concluded that the Ussing chamber can continuously analyze the process from digestion to absorption of proteins in the gastrointestinal tract.

Excessive immune response and inflammation are associated with an increased risk of various diseases. In particular, excessive myeloperoxidase (MPO) activity in neutrophils causes inflammatory reactions and lifestyle-related diseases. Adlay has a long history of being used as a traditional Chinese medicine. Polyphenols present in adlay seeds are expected to have the effect of suppressing excessive immune and inflammatory responses. Here, we conducted a randomized, double-blind, parallel group, placebo-controlled study was conducted to evaluate the suppressing effects of adlay seeds extract on excessive immune responses. One hundred and twenty adults participated in the study and they were equally divided into an adlay tea intake group and a placebo group. MPO activity was significantly elevated in the placebo group after 8-wk ingestion, while no significant change was observed in the adlay group. Vascular endothelial functions improved in the adlay group, especially in subjects over 40 y old. These results indicate that adlay tea intake may suppress an excessive immune and inflammatory responses, and improve arterial stiffness. Since caffeic acid, p-coumaric acid, and ferulic acid detected in adlay tea are known to inhibit MPO activity, these polyphenols may be the major functional molecules. Collectively, adlay tea is considered to have a preventative effect against lifestyle-related diseases through improving vascular endothelial function by effects to maintain immune homeostasis of the contained polyphenols. This trial was registered at University Hospital Medical Information Network Clinical Trials Registry (UMIN000032263).

As the aging process accelerates, the age structure of blood donors turns to older and even aged groups. Methylmalonic acid (MMA), a byproduct of propionate metabolism, may be upregulated in the serum of older adults. As a mediator of chronic disease and tumor progression, the MMA content in blood products has become the focus of research. Absolute concentrations of MMA in blood products were determined based on the liquid chromatography-tandem mass spectrometry, so as to analyze how they were affected by donors' age, sex, and frequency of blood donation. The MMA content in leukocyte-depleted suspended red blood cell (lds-RBC) was significantly higher than that in fresh plasma (p<0.0001). The MMA content among five age groups showed no difference in either fresh plasma or lds-RBCs. The MMA content in fresh plasma was similar in the parameters of the sex, whereas that in lds-RBCs was higher in males than that in females (p=0.035). There were no significant differences in MMA content when it comes to different frequencies of blood donors in either fresh plasma or lds-RBCs. Additionally, there was no significant difference or clear trend in the rate of elevated plasma MMA levels among different sexes, age groups, and blood donation frequency groups. MMA in the blood products from donors in China does not compromise the safety of blood transfusions for cancer patients. Nevertheless, there is a need to focus on MMA levels in Chinese and to develop race-specific and age-specific normal reference ranges.