[Show abstract][Hide abstract] ABSTRACT: Protein is a main nutrient involved in overall iron metabolism in vivo. In order to assess the prevention of iron deficiency anemia (IDA) by diet, it is necessary to confirm the influence of dietary protein, which coexists with iron, on iron bioavailability. We investigated the usefulness of the egg structural protein in recovery from IDA. Thirty-one female Sprague-Dawley rats were divided into a control group (n = 6) fed a casein diet (4.0 mg Fe/100 g) for 42 days and an IDA model group (n = 25) created by feeding a low-iron casein diet (LI, 0.4 mg Fe/100 g) for 21 days and these IDA rats were fed normal iron diet with different proteins from eggs for another 21 days. The IDA rats were further divided into four subgroups depending on the proteins fed during the last 21 days, which were those with an egg white diet (LI-W, 4.0 mg Fe/100 g, n = 6), those with an ovalbumin diet (LI-A, 4.0 mg Fe/100 g, n = 7), those with an egg yolk-supplemented diet (LI-Y, 4.0 mg Fe/100 g, n = 6), and the rest with a casein diet (LI-C, 4.0 mg Fe/100 g, n = 6). In the LI-Y group, recovery of the hematocrit, hemoglobin, transferrin saturation level and the hepatic iron content were delayed compared to the other groups (p < 0.01, 0.01, 0.01, and 0.05, respectively), resulting in no recovery from IDA at the end of the experimental period. There were no significant differences in blood parameters in the LI-W and LI-A groups compared to the control group. The hepatic iron content of the LI-W and LI-A groups was higher than that of the LI-C group (p < 0.05). We found that egg white protein was useful for recovery from IDA and one of the efficacious components was ovalbumin, while egg yolk protein delayed recovery of IDA. This study demonstrates, therefore, that bioavailability of dietary iron varies depending on the source of dietary protein.
[Show abstract][Hide abstract] ABSTRACT: We demonstrated that the indicator amino acid oxidation (IAAO) method could be employed for the evaluation of quality of dietary protein by comparing the protein intakes required to meet metabolic demand in rats fed different proteins. The objective of this study was to validate a simple evaluation method for determining the quality of dietary protein using the IAAO technique. Male Sprague-Dawley rats (5-6 wk old) were fed meals composed of graded protein, using either casein, wheat gluten (WG), soy protein isolate (SPI), or egg white protein (EW), every 3 h from 09:00 to 18:00. Administration of L-[1-(13)C]phenylalanine was performed hourly from 15:00 to 18:00. The (13)CO2 level in breath CO2 was measured at 18:30. The protein intake values required to meet the metabolic demand based on the breath (13)CO2 data for the dietary casein, WG, SPI, and EW intake were 18.0, 22.2, 17.5, and 10.1 g/kg BW/d, respectively. The breath (13)CO2 concentrations corresponding to the protein intake of 7.5 g/kg BW/d for casein, WG, SPI, and EW were 9.8, 10.9, 10.3, and 8.9 (‰)/100 g BW, respectively. A significant correlation was demonstrated between the protein intake required to meet the metabolic demands and the (13)CO2 concentration in the breath for a protein intake of 7.5 g/kg BW/d (r=0.967; p<0.05). These results demonstrated that the protein intake required to meet metabolic demand could be estimated and that the quality of the dietary protein could be evaluated using the (13)CO2 concentration in the breath with a protein intake of 7.5 g/kg BW/d.
Journal of Nutritional Science and Vitaminology 06/2015; 61(2):123-30. DOI:10.3177/jnsv.61.123 · 0.83 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Aims/IntroductionA low-carbohydrate diet based on animal sources was associated with higher all-cause mortality, whereas a vegetable-based low-carbohydrate diet was associated with lower cardiovascular disease mortality. Besides, it has been suggested that acid/base imbalance may play an important role in some cardiometabolic abnormalities. The aims of this study were to evaluate whether carbohydrate intake is associated with quality of dietary protein and acid load, and whether these related to metabolic syndrome (MetS) in patients with type 2 diabetes.Materials and Methods
This cross-sectional study involved 149 patients with type 2 diabetes. Dietary intake was assessed using a validated self-administered diet history questionnaire. Dietary acid load was assessed by potential renal acid load (PRAL) and net endogenous acid production (NEAP).ResultsMean daily total energy intake, carbohydrate intake, animal protein intake and vegetable protein intake were 1821.5kcal, 248.8g, 36.1g and 31.1g, respectively. Carbohydrate energy/total energy was negatively correlated with animal protein energy/total energy, PRAL or NEAP score, and was positively correlated with vegetable protein energy/total energy. Logistic regression analyses showed that the subgroup of patients with lower vegetable protein energy/total energy or higher PRAL or NEAP score was significantly associated with prevalence of MetS.Conclusions
Our study showed that carbohydrate intake was associated with quality of dietary protein and dietary acid load. Furthermore, decreased vegetable protein intake and increased dietary acid load were associated with prevalence of MetS.This article is protected by copyright. All rights reserved.
[Show abstract][Hide abstract] ABSTRACT: A precursor of protoporphyrin IX, 5-aminolevulinic acid (5-ALA) is employed as a prodrug for photodiagnosis and photodynamic therapy. Recently, it has been shown that 5-ALA reduces glucose levels during fasting and after glucose loading in prediabetic subjects. We hypothesized that 5-ALA ameliorates diabetic conditions through mitochondrial changes in visceral adipose tissue. In order to explore the metabolic effects on the type 2 diabetic state, we administered ALA hydrochloride in combination with sodium ferrous citrate (SFC) to Otsuka Long-Evans Tokushima Fatty (OLETF) rats at intragastric doses of 20 and 300 mg/kg/day for 6 weeks. The administration of 300 mg/kg/day of 5-ALA improved glucose intolerance, hypertriglyceridemia, and hyperleptinemia in OLETF rats more effectively than the administration of an equivalent dose of metformin, in accordance with reductions in food intake and body weight. Furthermore, the weight of the retroperitoneal fat tended to decrease and cellular mitochondrial content of the fat was markedly reduced by the 5-ALA administration, showing a positive correlation. These results suggest that 5-ALA ameliorates diabetic abnormalities in OLETF rats by reducing the visceral fat mass and mitochondrial content of adipocytes in a site-specific manner.
Nutrition Research 06/2014; 34(6). DOI:10.1016/j.nutres.2014.04.013 · 2.47 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Studies have indicated that sports anemia is mainly associated with intravascular hemolysis induced by exercise. We hypothesized that such exercise-induced hemolysis leads to oxidative damage due to an increase in free iron caused by hematocyte destruction. Thirty-one male ICR mice were randomly divided into 3 groups: a rested control group, an intense-exercise group, and a group rested for 24 hours after intense exercise. The serum haptoglobin level of the intense-exercise group decreased compared with that of the rested control group, suggesting hemolysis. Tissue iron and protein carbonyl levels in the liver were increased after exercise, and the protein carbonyl level in the spleen on the day after exercise was significantly increased compared with that of the resting state. These results suggest that the spleen and liver, where extravascular hemolysis occurs, were subjected to oxidative modification by the free iron, which was released from large numbers of hemocytes that were destroyed due to the intense exercise.
Nutrition and Metabolic Insights 01/2014; 7:1-6. DOI:10.4137/NMI.S13668
[Show abstract][Hide abstract] ABSTRACT: Medical nutrition therapy for the management of diabetes plays an important role in preventing diabetes complications and managing metabolic control. However, little is known about actual eating habits of individuals with type 2 diabetic mellitus (T2DM), especially in Japan. Therefore, we sought to (1) assess the dietary intake of individuals with T2DM, and (2) characterize their intake relative to national recommendations. This cross-sectional study involved 149 patients (77 males and 72 females) aged 40-79 years with T2DM recruited at a Kyoto hospital. Dietary intake was assessed using a validated self-administered diet history questionnaire. Under-consumption, adequacy, and over-consumption, of nutrients were compared to the age- and sex-based standards of the Japanese Dietary Reference Intakes. Among the results, most notable are (1) the inadequacy of diets in men with respect to intake of vitamins and minerals, likely owing to low intake of vegetables and fruits; (2) excess contributions of fat intake to total energy in both sexes; and (3) excess consumption of sweets and beverages relative to the national average. The prevalence of diabetes complications may be increasing because of a major gap between the typical dietary intake of individuals with T2DM and dietary recommendation.
[Show abstract][Hide abstract] ABSTRACT: Branched-chain amino acids (BCAA) can function as pharmacologic nutrients for patients with decompensated cirrhosis. However, the effects of BCAA at the early stage of chronic liver disease are not clear. We hypothesized that early BCAA supplementation would attenuate the progression of chronic liver disease. The present study examined the effects of BCAA supplementation on the progression of chronic liver disease in rats caused by injected carbon tetrachloride (CCl₄). Sprague-Dawley rats were fed with a casein diet (control group) or the same diet supplemented with BCAA (BCAA group) for 11 weeks, and all rats were repeatedly injected with CCl₄. Food intake did not significantly differ between control and BCAA groups during the experimental period. Plasma alanine aminotransferase activities gradually increased during the experimental period in both groups but peaked later in the BCAA group. Liver fibrosis was more evident in the control group. Levels of connective tissue growth factor messenger RNA were significantly lower in the livers of rats in the BCAA group than in the control group. Terminal deoxynucleotidyl transferase-mediated deoxyuridine 5-triphosphate nick end labeling assays found considerably more hepatic apoptosis in the control group. Liver cytosolic cytochrome c levels and expression of the proapoptotic Bax protein in the mitochondrial fraction were significantly lower in the BCAA group than in the control group. These results suggest that supplementation with BCAA delays the progression of chronic liver disease caused by CCl₄ in rats by attenuating hepatic apoptosis.
Nutrition research 07/2012; 32(7):522-9. DOI:10.1016/j.nutres.2012.06.007 · 2.47 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We examined whether continuous supplementation with branched-chain amino acids phosphorylates ribosomal protein S6, a downstream effector of mammalian target of rapamycin, and improves hypoalbuminemia of rats with chronic liver disease. Sprague-Dawley rats were fed a casein diet (control group) or a branched-chain amino acid-supplemented casein diet (branched-chain amino acid group) for 11 weeks with repeated injections of carbon tetrachloride. Throughout this experimental period, no significant difference in plasma albumin concentration was seen between groups. The percentage of reduced albumin within total plasma albumin gradually decreased in both control and branched-chain amino acid groups. After 11 weeks with supplementation, phosphorylation of ribosomal protein S6 was significantly increased in the liver of rats in the branched-chain amino acid group compared with the control group. Furthermore, the percentage of reduced albumin within total albumin was significantly higher in the branched-chain amino acid group than in the control group. These results indicate that continuous supplementation with branched-chain amino acids in rats with chronic liver disease induces phosphorylation of hepatic ribosomal protein S6 and attenuates decreases in the percentage of reduced albumin, although levels of plasma albumin are not increased.
Journal of Clinical Biochemistry and Nutrition 01/2012; 50(1):67-71. DOI:10.3164/jcbn.11-37 · 2.19 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Iron deficiency anemia (IDA) is one of the most serious forms of malnutrition. A promo-tion function of mineral absorption has been reported for neutral oligosaccharides, but not acidic xylooligosaccharide (U-XOS), which is a novel oligosaccharide. We hypothe-sized that U-XOS could promote recovery from IDA by enhancing the serum iron level. Therefore, the aim of this study was to investigate whether or not U-XOS was useful for recovery from IDA in the rat. Twenty-four female Sprague-Dawley rats were randomly divided into a control group fed a control diet (4.0 mg Fe /100 g) and an IDA model group created by employing a low-iron diet (0.4 mg Fe /100 g). The IDA group was further di-vided into three subgroups on day 21: U-XOS-supplemented diet (LI-X, 4.0 mg Fe /100 g), low-iron diet (LI), and control diet (LI-C) groups. No significant differences in the serum iron transferrin saturation levels were demonstrated between the control and LI-X groups on days 26 and 35. The divalent metal transporter 1 and ferroportin mRNA expression levels shown in the first segment of the small intestines showed a significant decrease in the LI-X group, compared with the LI group. A significant decrease in the hepatic hep-cidin mRNA expression level and iron content was also demonstrated in the LI-X group, compared with the control group, but not compared with the LI group. These results sug-gested that U-XOS could promote recovery from IDA by enhancing serum iron at an early stage of the recovery process.
[Show abstract][Hide abstract] ABSTRACT: Wheat gluten hydrolysate (WGH) has been reported to mitigate chronic hepatitis in some patients. We aimed to reproduce and examine this phenomenon in a rat experimental model. Male Sprague-Dawley rats were injected with carbon tetrachloride twice a week for 25 weeks, and 3 weeks later WGH was added to the feed (none, 4%, and 8%) for the remaining 22 weeks. Transition of serum transaminases showed a temporary decrease in aspartate aminotransferase (AST) and a delay in the peaking of alanine aminotransferase (ALT) in the WGH groups. Macroscopically, at the end of the 25 weeks, the progress of cirrhosis was milder in the WGH groups, as indicated by less ascites fluid and the fewer tubercle formations. Histological and immunohistochemical analyses of the liver revealed fewer collagen fibers and less -smooth muscle actin (SMA) in the 8% WGH group. The ethanol-soluble extract of liver tissue showed plasmin inhibiting activity in the 8% WGH group. The observed modification of the transition of serum transaminases during chronic CCl4 challenge supports the possibility that WGH mitigates chronic hepatitis, and the liver manifestations after 25 weeks of CCl4 treatment indicate that WGH ingestion alters the progress of cirrhosis
Biomedical Research 04/2011; 22(1):481-488. · 0.24 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Iron deficiency anemia (IDA) is one of the most serious forms of malnutrition. This experiment was conducted to investigate whether acidic xylooligosaccharide (U-XOS), expected to have a high iron bioavailability, was useful in the prevention of iron deficiency. Experiment 1: Nineteen female Sprague-Dawley rats (20 wk old) were fed three different diets for 28 d; a U-XOS-supplemented low-iron diet (LI-X, n=7), a low-iron diet (LI, n=6), and a control diet (C, n=6). On day 28, the LI-X and LI groups showed iron deficiency without anemia. A significant difference in the total and unsaturated iron binding capacity, and serum transferrin saturation level was shown in the LI-X and LI groups, compared with the C group. However, the decrease of hepatic iron content of the LI-X group was suppressed compared with the LI group. Experiment 2: Eleven male Sprague-Dawley rats (7 wk old) were fed a U-XOS-supplemented diet (X, n=5) or a control diet (C, n=6) for 7 d. No significant difference in body weight gain or food intake was demonstrated between the two groups; the apparent iron absorption rate of the X group increased clearly compared with that of the C group. These results suggested that a U-XOS diet could preserve storage of hepatic iron in adult female rats fed a low-iron diet and could prevent IDA by promotion of dietary iron absorption, inhibition of iron excretion, and/or improvement of iron bioavailability.
Journal of Nutritional Science and Vitaminology 01/2011; 57(4):292-7. DOI:10.3177/jnsv.57.292 · 0.83 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The objective of this study was to investigate the effects of dietary medium-chain triglycerides (MCT) on hepatic lipid accumulation in growing rats with protein malnutrition. Weaning rats were fed either a low-protein diet (3%, LP) or control protein diet (20%, CP), in combination with or without MCT. The four groups were as follows: CP-MCT, CP+MCT, LP-MCT, and LP+MCT. Rats in the CP-MCT, CP+MCT and LP+MCT groups were pair-fed their respective diets based on the amount of diet consumed by the LP-MCT group. Rats were fed each experimental diet for 30 d. Four weeks later, the respiratory quotient was higher in the LP-MCT group than those in the other groups during the fasting period. Hepatic triglyceride content increased in the LP groups compared with the CP groups. Hepatic triglyceride content in the LP+MCT group, however, was significantly decreased compared with that in the LP-MCT group. Levels of carnitine palmitoyltransferase (CPT) 1a mRNA and CPT2 mRNA were significantly decreased in the livers of the LP-MCT group, as compared with corresponding mRNA levels of the other groups. These results suggest that ingestion of a low-protein diet caused fatty liver in growing rats. However, when rats were fed the low-protein diet with MCT, hepatic triglyceride deposition was attenuated, and mRNA levels encoding CPT1a and CPT2 were preserved at the levels of rats fed control protein diets.
Journal of Nutritional Science and Vitaminology 01/2011; 57(2):138-43. DOI:10.3177/jnsv.57.138 · 0.83 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Currently, protein requirements are generally determined based on nitrogen balance studies, but there are a variety of limitations associated with this method. The indicator amino acid oxidation (IAAO) method, with a theoretical base that differs widely from the nitrogen balance method, was developed as an alternative method for humans. The objective of the present study was to evaluate protein intakes for metabolic demands and protein quality, using protein itself, in rats employing the IAAO technique with L-[1-(13)C]phenylalanine. Male Wistar/ST rats (5-6 wk old) received a graded casein (4.3, 8.6, 12.9, 17.2, 21.5, 25.8%), or a wheat gluten (7.2, 10.8, 14.4, 18.0, 21.6, 25.2%) diet, along with L-[1-(13)C]phenylalanine. An isotopic plateau in breath was achieved 210 min after the start of the (13)C ingestion. The protein intakes for metabolic demands were calculated by applying a mixed-effect change-point regression model to breath (13)CO(2) data, which identified a breakpoint at minimal breath (13)CO(2) in response to graded protein intake. The protein intakes for metabolic demands determined by the IAAO method were 13.1 g/kg BW/d for casein and 18.1 g/kg BW/d for wheat gluten, showing a tendency similar to that determined by the nitrogen balance method. These results demonstrated that the IAAO method could be employed to evaluate not only the protein intakes for metabolic demands, but the dietary protein quality in freely living rats, suggesting that this method might be viable in a clinical setting.
Journal of Nutritional Science and Vitaminology 01/2011; 57(6):418-25. DOI:10.3177/jnsv.57.418 · 0.83 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Diabetic nephropathy is associated with lipid deposits in the kidney. We hypothesized that a diet containing polyunsaturated fatty acids (PUFAs) could ameliorate pathogenesis of diabetic kidney diseases associated with lipid depositions in the kidneys. We examined if the pathogenesis and progression of diabetic nephropathy are affected by the type of dietary fat using streptozotocin (45 mg/kg body weight, intravenous)-induced diabetic rats (5-week-old male Sprague-Dawley rats). Streptozotocin-induced diabetic rats were fed a lard diet containing saturated fatty acids or a rapeseed oil diet containing PUFAs (DML and DMR, respectively) for 11 days. Similarly, streptozotocin-nontreated rats were fed a lard diet or a rapeseed oil diet (NL and NR, respectively) for 11 days. Hyperglycemia was induced in DML and DMR, compared with NL and NR groups. The levels of plasma ketone, total cholesterol, and triglyceride (TG) were significantly increased in the DML group. Moreover, albuminuria and renal TG content were enhanced in the DML group. The renal TG content correlated positively with urinary albumin excretion (P < .001). Oil-Red O staining of kidney sections indicated a marked accumulation of neutral lipids in both glomerular and tubular cells in the DML group. In addition, a renal sterol regulatory element-binding protein-1 mature protein increment was induced in the DML group. Conversely, sterol regulatory element-binding protein-1 expression in the kidney was maintained at normal levels in the DMR group. These results suggest that dietary PUFAs may slow the progression of diabetic nephropathy associated with lipid depositions in the kidney.
Nutrition research 03/2010; 30(3):217-25. DOI:10.1016/j.nutres.2010.03.002 · 2.47 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We examined whether two types of xylooligosaccharides (neutral or acidic xylooligosaccharides) derived from hardwood kraft pulp ameliorate the development of atopic dermatitis (AD)-like skin lesions induced by repeated application of picryl chloride (PiCl) in NC/Nga mice. Oral administration of acidic xylooligosaccharides at a daily dose of 100 mg/kg significantly prevented the development of AD-like skin lesions. Serum histamine level was significantly suppressed, but serum total IgE level was not significantly suppressed. Moreover, the secretion of inflammatory cytokine IL-12 from splenic lymphocytes was significantly suppressed. On the other hand, neutral xylooligosaccharides showed no significant preventive effect on the development of AD-like symptoms. These results suggest that oral administration of acidic xylooligosaccharides may be effective in preventing the development of AD-like skin disease and one of the mechanisms is the suppressive effect on IL-12.
Journal of Nutritional Science and Vitaminology 01/2010; 56(1):54-9. DOI:10.3177/jnsv.56.54 · 0.83 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The introduction of the tumorigenic v-Ha-ras oncogene-transformed rat liver epithelial cells (WBras), which is deficient in gap junctional intercellular communication (GJIC), into F344 rats, induces significant formation of hepatocellular tumors. GJIC plays a major role in maintaining tissue homeostasis. Using this in vivo tumor model system, we used 2-dimensional electrophoresis with isoelectric focusing in the first dimension and SDS-PAGE in the second dimension to globally identify proteins that are uniquely expressed in the livers of WBras-treated rats as compared to the sham control. Immunoblotting was used to identify Ras and Connexin43, which were the positive and negative marker proteins, respectively, of the introduced WBras cells. As predicted, immunoblotting indicated that the whole liver of tumor-bearing animals exhibited a decreased level of Connexin43 and an increased level of Ras. Connexin43 and GJIC were expressed and functional in normal liver, but not in the tumor. In addition to these 2 markers, an additional 4 proteins exhibited decreased levels and 2 proteins exhibited increased levels in the livers of tumor-bearing animals. N-Terminal sequencing analysis was used to identify these proteins, which were glucose-regulated protein 78, 2 isoforms of heat shock protein 60, and the beta-chain of ATP synthase for the down regulated proteins, and beta-Actin with a 46 amino acid deletion from its N-terminus and Vimentin with a 71 amino acid deletion from its N-terminus for the up regulated proteins. These data offer potentially new markers of liver tumorigenicity, particularly, Vimentin. (
International Journal of Cancer 06/2009; 124(11):2512-9. DOI:10.1002/ijc.24229 · 5.09 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Our recent study demonstrates that polypyrimidine tract-binding protein (PTB), which is a sequence specific RNA-binding protein, attenuates albumin synthesis in a cell-free translation system. In this study, the effects of food intake on regulation of albumin synthesis through binding of PTB to albumin messenger RNA (mRNA) were investigated. Rats were divided into 1 of 3 groups: fed; fasted for 36 h; or fasted for 36 h and then refed for 24 h. No significant differences in albumin mRNA levels were found among fed, fasted and refed rats. However, a decrease in the proportion of albumin mRNA associated with polysomes was identified in fasted rats. Furthermore, UV-cross linking analysis demonstrated that levels of albumin mRNA-PTB complex were increased in liver extracts from fasted rats. No significant differences in PTB levels in liver homogenate were found among the experimental groups. However, PTB level in the cytoplasmic fraction was higher in fasted rats than in fed rats. In refed rats, PTB level in the cytoplasmic fraction returned to a level comparable to that in fed rats, but was inhibited by treatment with rapamycin, a mammalian target of rapamycin (mTOR) inhibitor. These results suggest that localization of PTB is regulated by food intake through mTOR signaling, and alterations in level of albumin mRNA-PTB complex play a role in mediating the effects of food intake on albumin synthesis in the rat liver.
Journal of Nutritional Science and Vitaminology 05/2008; 54(2):142-7. DOI:10.3177/jnsv.54.142 · 0.83 Impact Factor