We examined the effect of vitamin E depletion on liver oxidative damage in rats with water-immersion restraint stress (WIRS). Male Wistar rats were fed a normal diet (N) or vitamin E-depleted diet (VE-D) for 4 wk. N- and VE-D-fed rats were exposed to WIRS for 6 h. The activities of serum transaminases and lactate dehydrogenase and serum ascorbic acid concentration were similar in both diet groups. WIRS exposure increased these serum enzyme activities and the serum ascorbic acid concentration in both diet groups but the ratios of these increases were higher in VE-D-fed rats than in N-fed rats. Serum and liver α-tocopherol concentrations in VE-D-rats were approximately 50% and 30% of those in N-fed rats, respectively. WIRS exposure reduced liver α-tocopherol concentration in VE-D-fed rats, but not in N-fed rats. Liver ascorbic acid and reduced glutathione concentrations were higher in the VE-D-fed group than in the N-fed group. WIRS exposure reduced liver ascorbic acid and reduced glutathione concentrations in both diet groups. There were no differences in liver concentrations of coenzyme Q9 or coenzyme Q10 in the reduced form between the N- and VE-D-fed groups. WIRS exposure reduced liver concentrations of coenzyme Q9 and coenzyme Q10 in the reduced form in both diet groups. Liver lipid peroxide concentration was higher in the VE-D-fed group than in the N-fed group. WIRS exposure raised liver lipid peroxide concentration more in the VE-D-fed group than in the N-fed group. These results indicate that vitamin E depletion enhances liver oxidative damage in rats with WIRS.
It is thought that increasing energy expenditure increases consumption of vitamin B1, leading to an increase in the requirement of vitamin B1. However, evidence supporting this hypothesis is lacking. To examine the hypothesis, initially, we determined the minimum requirement of vitamin B1 for weaning rats. We found that the minimum requirement of vitamin B1 for optimum growth of weaning rats was around 0.786 mg thiamin/kg diet. Next, rats fed a diet containing the minimum requirement of vitamin B1 were forced to swim until exhaustion. Concentrations of vitamin B1 in the blood and liver as well as urinary excretion of swimming rats decreased significantly compared with those of non-swimming rats (p<0.05), while in rats fed the diet containing a sufficient amount of vitamin B1 (4.720 mg thiamin/kg diet), vitamin B1 amounts in the blood, liver and urine were not affected by swimming. We clearly and firstly showed the reduction of body vitamin B1 following increases in energy expenditure.
D-Pantethine is a compound in which two molecules of D-pantetheine bind through an S-S linkage. D-Pantethine is available from commercial sources as well as from D-pantothenic acid. We investigated if D-pantethine has the same vitamin activity as D-pantothenic acid by comparing the recovery from a deficiency of D-pantothenic acid in rats. D-Pantothenic acid-deficient rats were developed by weaning rats on a diet lacking D-pantothenic acid for 47 d. At that time, the urinary excretion of D-pantothenic acid was almost zero, and the body weight extremely low, compared with the control (p<0.05); the contents of free D-pantothenic acid were also significantly reduced in comparison with those of controls (p<0.05). D-Pantothenic acid-deficient rats were administered a diet containing D-pantothenic acid or D-pantethine for 7 d. D-Pantethine and D-pantothenic acid contents of the diets were equimolar in forms of D-pantothenic acid. We compared various parameters concerning nutritional status between rats fed D-pantothenic acid- and D-pantethine-containing diets. The recoveries of body weight, tissue weights, and tissue concentrations of free D-pantothenic acid, dephospho-CoA, CoA, and acetyl-CoA were identical between rats fed diets containing D-pantothenic acid and D-pantethine. Thus, the biological efficiency for recovering from a deficiency of D-pantothenic acid in rats was equivalent between D-pantothenic acid and D-pantethine.
Obesity has increased in children and adolescents. What is reflected in the early occurrence of cardiometabolic alterations, like hypertension and type 2 diabetes, where the oxLDL formation is stimulated. Various studies have shown that plasma α-tocopherol (α-TP) can protect LDL against oxidation. Nevertheless, the action of plasma α-TP in cardiovascular diseases remains controversial. We conducted a cross-sectional study to evaluate plasma α-TP and its impact on the concentration of LDL(−). Adolescents (n=150) of both sexes were classified into three groups: healthy weight (HW; 50%), overweight (OV; 22%), and obese (OB; 28%). Lipid profile, LDL(−), anti-oxLDL and anti-LDL(−) antibodies, CRP (ELISA) and plasma α-TP (HPLC) were analyzed. Demographic, anthropometric, and food intake data were evaluated. Crude and energy-adjusted intake of vitamin E in the OB group were higher than in the HW group (p<0.001). Crude and energy-adjusted vitamin E intakes were not correlated with plasma α-TP (r=−0.07; p=0.412 and r=−0.064; p=0.467, respectively). Subjects in the OB group had higher TC and LDL-C and lower HDL-C than in the HW and OV groups. C-reactive protein and anti-oxLDL antibodies changed as a function of BMI. The impact of obesity was reinforced by high values for LDL(−) and low content of plasma α-TP in comparison with the HW (p<0.001) and OV groups (p=0.03). This negative profile was maintained for the ratio between α-TP and TC or LDL-C. Plasma α-TP, α-TP/TC and α-TP/LDL-C were negatively associated with LDL(−) and other cardiometabolic risk factors (BMI, WC, AC and anti-oxLDL). Our results demonstrate that obesity in adolescents is associated with high levels of LDL(−) and low plasma α-TP content.
The relationship between γ-glutamyltransferase (γ-GTP) and C-reactive protein (CRP) has not been established, particularly in the lean or non-overweight population. In the present study, we examined the associations between γ-GTP and CRP in non-overweight and overweight middle-aged Japanese men. We conducted a cross-sectional study of 4,271 apparently healthy men aged 40 to 64 y (mean±SD, 50.5±6.6 y) who participated in health checkups. Associations between serum CRP levels, other clinical parameters, and lifestyle factors were analyzed using Spearman's rank correlation coefficient analysis and multiple linear regression analysis in the non-overweight (body mass index [BMI]<25 kg/m2) and overweight (BMI≥25 kg/m2) men. Associations between serum γ-GTP activity and serum CRP levels were analyzed using analysis of covariance by comparisons of serum CRP levels of four subgroups according to γ-GTP status. In non-overweight men, BMI, high-density lipoprotein cholesterol, triacylglycerols, fasting blood glucose, aspartate aminotransferase, γ-GTP, and smoking habit were positively associated with serum CRP levels. In overweight men, BMI, diastolic blood pressure, triacylglycerols, and γ-GTP were positively associated with serum CRP levels. After adjustment for age, BMI, smoking status, and alcohol intake, dose-response relationships were observed between γ-GTP and CRP levels in both overweight and non-overweight men. The results of this study indicate that an increase in serum γ-GTP activity is closely associated with elevated CRP levels in both non-overweight and overweight middle-aged Japanese men.
Although several studies have reported associations of depressive state with specific nutrients and foods, few have examined the associations with dietary patterns in adults. We investigated the association between major dietary patterns and depressive symptoms in Japanese patients with depression. Subjects were 166 Japanese patients (104 men and 62 women), aged 22-74 y, who were treated at a hospital psychiatry clinic in Tokyo. Depressive symptoms were assessed using the Himorogi Self-rating Depression Scale (H-SDS) and Himorogi Self-rating Anxiety Scale (H-SAS). We categorized depressive symptoms into 3 types: physical, psychiatric, and anxiety symptoms. Dietary patterns were derived using principal component analysis of the consumption of 59 food and beverage items, which was assessed by a validated brief diet history questionnaire. Three dietary patterns were identified: 1) “plant foods and fish products,” 2) “fish,” and 3) “Western/meat.” We calculated the correlation coefficients for the relationship between each dietary pattern score and depressive symptom score in unipolar depression vs. bipolar depression and in men vs. women. In bipolar depression, the plant foods and fish products pattern showed an inverse relationship with physical and psychiatric symptoms, and in men, this pattern showed an inverse relationship with psychiatric symptoms. The fish pattern and Western/meat pattern were not significantly associated with the 3 types of depressive symptoms. In conclusion, we identified 3 dietary patterns and found that associations between these patterns and depressive symptoms were observed only in bipolar depression and only in men.
Recent studies have shown that medium-chain triacylglycerol (MCT) improved serum albumin concentration in elderly people with protein-energy malnutrition (PEM) and in malnourished rats. However, the mechanism for this effect has not been clarified. Dietary MCT promotes insulin secretion from the pancreas, and insulin activates mammalian target of rapamycin (mTOR) complex 1 (mTORC1) via the activation of phosphoinositide 3-kinase (PI3K) and its downstream effecter, Akt. mTORC1 promotes mRNA translation through S6K and 4E-BP1. Therefore, we hypothesized that dietary MCT elevates albumin synthesis through promotion of insulin-Akt-mTOR transduction in the liver. To test this hypothesis, we measured phosphorylated Akt, mTOR and albumin in the livers of malnourished rats. In the present study we examined rats fed low-protein diets containing either MCT or long-chain triacylglycerol (LCT) with energy restriction. The plasma and liver albumin levels were significantly higher in the MCT-fed group than in the LCT-fed group. In addition, plasma insulin concentration, liver phosphorylated Akt/Akt and phosphorylated mTOR/mTOR levels were significantly higher in the MCT-fed group than in the LCT-fed group. These results suggest that one of the mechanisms for the albumin improvement effect of dietary MCT is the promotion of albumin synthesis through the insulin-Akt-mTOR signaling pathway of the liver.
The use of monosodium glutamate (MSG) as a flavor enhancer spans more than 100 y and there are many studies indicating the safety of general use of MSG. Recently, however, Collison et al. (2010) reported a two-generation study with a low dose of MSG that caused abdominal obesity, insulin resistance and dyslipidemia in mice. Due to public health concerns over metabolic syndrome, their report merits careful analysis. The present study attempted to repeat the Collison et al. findings. Groups of male or female C57BL/6J mice were fed a control diet or one supplemented with high-fructose corn syrup (HFCS) at a level of 20%. Drinking water control was provided or treatment groups were given 0.064% MSG solution (w/v). Diets and MSG administration continued throughout mating and during gestation and lactation periods. To further investigate the effects of ingestion of MSG, the offspring were continued on the same dosing conditions until they reached 32 wk of age. MSG administration in mice fed a normal or a HFCS diet throughout gestation and for 32 wk after birth, did not affect growth, girth size, abdominal fat weight or body composition. This study reports that MSG did not trigger insulin resistance, dyslipidemia or hepatic steatosis, regardless of the diet, not reproducing the results of the above-mentioned study (Collison et al., 2010).
The effects of dietary sialic acid in dams on the learning abilities of their pups after weaning were investigated using rats deficient in n-3 fatty acids. Nine-week-old female Wistar rats were fed an n-3 fatty acid-deficient diet for 3 wk and were mated at 12 wk of age. During pregnancy and lactation, the female rats were fed the n-3 fatty acid-deficient diet, and were given water or water containing 1% N-acetylneuraminic acid (NANA) ad libitum. After weaning, the learning abilities of the pups were evaluated using a novel object recognition test. The recognition index of pups nursed by dams fed on water containing 1% NANA (NANA-intake dams) was significantly higher than that of pups nursed by dams fed only on water (NANA non-intake dams). There were no significant differences in the total sialic acid or docosahexaenoic acid contents in the cerebral cortex or hippocampus of pups nursed by dams fed on either type of water. The total dimethylacetal (DMA, from plasmalogen) level in the cerebral cortex of pups nursed by NANA-intake dams was significantly higher than that of pups nursed by NANA non-intake dams. These results suggest that dietary sialic acid in dams during pregnancy and lactation might be beneficial for the learning abilities of pups after weaning, which may be related to the plasmalogen level in the brain of pups.
The aim of the present study was to determine the effect of oral administration of Lactobacillus plantarum OLL2712 (L. plantarum OLL2712) on glucose and lipid metabolism in mice with high-fat diet-induced obesity. Mice that had been administered 109 cfu heat-killed L. plantarum OLL2712 for 12 wk showed significant reduction of blood glucose levels in response to insulin. Furthermore, mRNA expression of interleukin-1β in adipose tissue and serum levels of nonesterified fatty acids in mice administered L. plantarum OLL2712 were significantly lower than those in control mice. These results indicate that L. plantarum OLL2712 regulates glucose metabolism.
Vitamin E is the generic name for tocopherol (Toc) and tocotrienol (T3), which have saturated and unsaturated side chains, respectively. Such differences allow T3 to be different from Toc in terms of their functions. T3 has been known to attenuate cholesterol (Cho) level by inhibiting 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG-CoAR). Recent reports also showed the efficacy of T3 in improving triglyceride (TG) profiles in both in vivo and in vitro studies. However the mechanism involved in this biological activity is still unclear and needs to be further investigated. In the present study, we elucidated the effect of γ-T3 on lipid levels and lipogenic gene expressions in mouse hepatocellular carcinoma Hepa 1-6. γ-T3 showed attenuation of TG through effect on fatty acid synthase, sterol regulatory element-binding transcription factor 1, stearoyl CoA desaturase 1, and carnitine palmitoyl transferase 1A gene expression in Hepa 1-6. In contrast, the Cho level remained unchanged. These results expanded our previous finding of lipid-lowering effects of T3, especially for TG. Therefore, T3 is a potential lipid-lowering compound candidate with realistic prospects for its use as a therapy for lipid-related diseases in humans.
γ-Aminobutyric acid (GABA) is an amino acid found in unpolished rice, chocolate, tea, and other foods. It is an important inhibitory neurotransmitter. However, the influence of GABA on object recognition and working memory is still unknown. In this study, the effects of GABA on novel object recognition (NOR) memory and working memory were examined. The proper retention interval and delay time were also investigated for the NOR test and T-maze test, respectively. Male 3-wk-old Wistar rats were allowed free access to food and water containing 0.5% GABA or 1% GABA for a month. After that, the rats performed the NOR test at a 48 h retention interval and T-maze test at a 900 s delay time to estimate the effects of GABA on learning behavior. The results showed that the object information in the NOR test was stored as long-term memory and the recognition index (RI) was significantly increased after GABA administration. The accuracy rate also significantly increased after GABA administration. These indicate that GABA may be involved in long-term object recognition memory and working memory.