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The present study was conducted to evaluate the effects of glucose, soya oil or glutamine on jejunal morphology, protein metabolism and protein expression of the mammalian target of rapamycin complex 1 (mTORC1) signalling pathway in jejunal villus or crypt compartment of piglets. Forty-two 21 d-weaned piglets were randomly allotted to one of the three isoenergetic diets formulated with glucose, soya oil or glutamine for 28 d. On day 14 or 28, the proteins in crypt enterocytes were analysed with isobaric tags for relative and absolute quantification and proteins involved in mTORC1 signalling pathway in villus or crypt compartment cells were determined by Western blotting. Our results showed no significant differences (P > 0·05) in jejunal morphology among the three treatments on day 14 or 28. The differentially expressed proteins mainly took part in a few network pathways, including antimicrobial or inflammatory response, cell death and survival, digestive system development and function and carbohydrate metabolism. On day 14 or 28, there were higher protein expression of eukaryotic initiation factor-4E binding protein-1 in jejunal crypt compartment of piglets supplemented with glucose or glutamine compared with soya oil. On day 28, higher protein expression of phosphor-mTOR in crypt compartment was observed in piglets supplemented with glucose compared with the soya oil. In conclusion, the isoenergetic glucose, soya oil or glutamine did not affect the jejunal morphology of piglets; however, they had different effects on the protein metabolism in crypt compartment. Compared with soya oil, glucose or glutamine may be better energy supplies for enterocytes in jejunal crypt compartment.
Despite the well-characterised mechanisms of amino acids (AA) regulation of milk protein synthesis in mammary glands (MG), the underlying specific AA regulatory machinery in bovine MG remains further elucidated. As methionine (Met) is one of the most important essential and limiting AA for dairy cows, it is crucial to expand how Met exerts its regulatory effects on dairy milk protein synthesis. Our previous work detected the potential regulatory role of seryl-tRNA synthetase (SARS) in essential AA (EAA)-stimulated bovine casein synthesis. Here, we investigated whether and how SARS participates in Met stimulation of casein production in bovine mammary epithelial cells (BMEC). With or without RNA interference against SARS, BMEC were treated with the medium in the absence (containing all other EAA and devoid of Met alone)/presence (containing 0·6 mm of Met in the medium devoid of Met alone) of Met. The protein abundance of β-casein and members of the mammalian target of rapamycin (mTOR) and general control nonderepressible 2 (GCN2) pathways was determined by immunoblot assay after 6 h treatment, the cell viability and cell cycle progression were determined by cell counting and propidium iodide-staining assay after 24 h treatment, and protein turnover was determined by l-[ring-3H5]phenylalanine isotope tracing assay after 48 h treatment. In the absence of Met, there was a general reduction in cell viability, total protein synthesis and β-casein production; in contrast, total protein degradation was enhanced. SARS knockdown strengthened these changes. Finally, SARS may work to promote Met-stimulated β-casein synthesis via affecting mTOR and GCN2 routes in BMEC.
The present study aimed to investigate whether arginine (Arg) promotes porcine type I muscle fibres formation via improving mitochondrial biogenesis. In the in vivo study, a total of sixty Duroc × Landrace × Yorkshire weaning piglets with an average body weight of 6·55 (sd 0·36) kg were randomly divided into four treatments and fed with a basal diet or a basal diet supplemented with 0·5, 1·0 and 1·5 % l-Arg, respectively, in a 4-week trial. Results showed that dietary supplementation of 1·0 % Arg significantly enhanced the activity of succinate dehydrogenase, up-regulated the protein expression of myosin heavy chain I (MyHC I) and increased the mRNA levels of MyHC I, troponin I1, C1 and T1 (Tnni1, Tnnc1 and Tnnt1) in longissimus dorsi muscle compared with the control group. In addition, ATPase staining analysis indicated that 1·0 % Arg supplementation significantly increased the number of type I muscle fibres and significantly decreased the number of type II muscle fibres. Furthermore, 1·0 % Arg supplementation significantly up-regulated PPAR-γ coactivator-1α (PGC-1α), sirtuin 1 and cytochrome c (Cytc) protein expressions, increased PGC-1α, nuclear respiratory factor 1 (NRF1), mitochondria transcription factor B1 (TFB1M), Cytc and ATP synthase subunit C1 (ATP5G) mRNA levels and increased mitochondrial DNA content. In the in vitro study, mitochondrial complex I inhibitor rotenone (Rot) was used. We found that Rot annulled Arg-induced type I muscle fibres formation. Together, our results provide for the first time the evidence that Arg promotes porcine type I muscle fibres formation through improvement of mitochondrial biogenesis.
Consumption of a high-fat diet increases fat accumulation and may further lead to inflammation and hepatic injuries. The aim of the study was to investigate the effects of Camellia oleifera seed extract (CSE) on non-alcoholic fatty liver disease (NAFLD). After a 16-week NAFLD-inducing period, rats were assigned to experimental groups fed an NAFLD diet with or without CSE. At the end of the study, we found that consuming CSE decreased the abdominal fat weight and hepatic fat accumulation and modulated circulating adipokine levels. We also found that CSE groups had lower hepatic cytochrome P450 2E1 and transforming growth factor (TGF)-β protein expressions. In addition, we found that CSE consumption may have affected the gut microbiota and reduced toll-like receptor (TLR)-4, myeloid differentiation primary response gene 88, toll/IL-1 receptor domain-containing adaptor-inducing interferon-β (TRIF) expression and proinflammatory cytokine concentrations in the liver. Our results suggest that CSE may alleviate the progression of NAFLD in rats with diet-induced steatosis through reducing fat accumulation and improving lipid metabolism and hepatic inflammation.
Glucose intolerance during pregnancy – a major driver of gestational diabetes mellitus (GDM) – has significant short- and long-term health consequences for both the mother and child. As GDM prevalence continues to escalate, there is growing need for preventative strategies. There is limited but suggestive evidence that myo-inositol (MI) and probiotics (PB) could improve glucose tolerance during pregnancy. The present study tested the hypothesis that MI and/or PB supplementation would reduce the risk of glucose intolerance during pregnancy. Female C57BL/6 mice were randomised to receive either no treatment, MI, PB (Lactobacillus rhamnosus and Bifidobacterium lactis) or both (MIPB) for 5 weeks. They were then provided with a high-fat diet for 1 week before mating commenced and throughout mating/gestation, while remaining on their respective treatments. An oral glucose tolerance test occurred at gestational day (GD) 16·5 and tissue collection at GD 18·5. Neither MI nor PB, separately or combined, improved glucose tolerance. However, MI and PB both independently increased adipose tissue expression of Ir, Irs1, Akt2 and Pck1, and PB also increased Pparγ. MI was associated with reduced gestational weight gain, whilst PB was associated with increased maternal fasting glucose, total cholesterol and pancreas weight. These results suggest that MI and PB may improve insulin intracellular signalling in adipose tissue but this did not translate to meaningful differences in glucose tolerance. The absence of fasting hyperglycaemia or insulin resistance suggests this is a very mild model of GDM, which may have affected our ability to assess the impact of these nutrients.
Misalignment of day/night and feeding rhythms has been shown to increase fat deposition and the risk for metabolic disorders in humans and rodents. In most studies, however, food intake and intake patterns are not controlled. We studied the effects of circadian misalignment on energy expenditure in pigs while controlling for food intake as well as intake patterns. Twelve groups of five male pigs were housed in respiration chambers and fed either during the day (10.00–18.00 hours; DF) or night (22.00–06.00 hours; NF), bihourly the same sequential meals, representing 15, 10, 25, 30 and 20 % of the daily allowance. Paired feeding was applied to ensure equal gross energy intake between treatments. Apparent total tract digestibility, energy balances and heat partitioning were measured and analysed using a mixed linear model. Apparent total tract energy and DM digestibility tended to be lower for NF-pigs than DF-pigs (P < 0·10). Heat production was 3 % lower for NF-pigs than DF-pigs (P < 0·026), increasing fat retention by 7 % in NF-pigs (P = 0·050). NF-pigs were less active than DF-pigs during the feeding period, but more active during the fasting period. RMR was greater for DF-pigs than NF-pigs during the fasting period. Methane production was 30 % greater in NF-pigs than DF-pigs (P < 0·001). In conclusion, circadian misalignment has little effect on nutrient digestion, but alters nutrient partitioning, ultimately increasing fat deposition. The causality of the association between circadian misalignment and methane production rates remains to be investigated.
We investigated whether non-digestible saccharide fermentation-derived hydrogen molecules (H2) in rat colon could improve the in vivo reduction–oxidation (redox) balance via regeneration of α-tocopherol, by assessing their effect on hydroxyl radicals, the α-tocopherol concentration and the redox balance. In Expt 1, a Fenton reaction with phenylalanine (0 or 1·37 mmol/l of H2) was conducted. In Expt 2, rats received intraperitoneally maize oil containing phorone (400 mg/kg) 7 d after drinking ad libitum water containing 0 or 4 % fructo-oligosaccharides (FOS) (groups CP and FP, respectively). In Expt 3, rats unable to synthesise ascorbic acid drank ad libitum for 14 d water with 240 mg ascorbic acid/l (group AC), 20 mg of ascorbic acid/l (group DC) or 20 mg of ascorbic acid/l and 4 % FOS (group DCF). In the Fenton reaction, H2 reduced tyrosine produced from phenylalanine to 72 % when platinum was added and to 92 % when platinum was excluded. In Expt 2, liver glutathione was depleted by administration of phorone to rats. However, compared with CP, no change in the m-tyrosine concentration in the liver of FP was detected. In Expt 3, net H2 excretion was higher in DCF than in the other rats after 3 d of the experiment. Furthermore, the concentrations of H2 and α-tocopherol and the redox glutathione ratio in perirenal adipose tissue of rats were significantly higher in DCF than in DC. To summarise, in rat colon, fermentation-derived H2 further shifted the redox balance towards a more reducing status in perirenal adipose tissue through increased regeneration of α-tocopherol.
Industrial heat treatment of milk results in protein glycation. A high protein glycation level has been suggested to compromise the post-prandial rise in plasma amino acid availability following protein ingestion. In the present study, we assessed the impact of glycation level of milk protein on post-prandial plasma amino acid responses in humans. Fifteen healthy, young men (age 26 (SEM 1) years, BMI 24 (SEM 1) kg/m2) participated in this randomised cross-over study and ingested milk protein powder with protein glycation levels of 3, 20 and 50 % blocked lysine. On each trial day, arterialised blood samples were collected at regular intervals during a 6-h post-prandial period to assess plasma amino acid concentrations using ultra-performance liquid chromatography. Plasma essential amino acid (EAA) concentrations increased following milk protein ingestion, with the 20 and 50 % glycated milk proteins showing lower overall EAA responses compared with the 3 % glycated milk protein (161 (SEM 7) and 142 (SEM 7) v. 178 (SEM 9) mmol/l × 6 h, respectively; P ≤ 0·011). The lower post-prandial plasma amino acid responses were fully attributed to an attenuated post-prandial rise in circulating plasma lysine concentrations. Plasma lysine responses (incremental AUC) following ingestion of the 20 and 50 % glycated milk proteins were 35 (SEM 4) and 92 (SEM 2) % lower compared with the 3 % glycated milk protein (21·3 (SEM 1·4) and 2·8 (SEM 0·7) v. 33·3 (SEM 1·7) mmol/l × 6 h, respectively; P < 0·001). Milk protein glycation lowers post-prandial plasma lysine availability in humans. The lower post-prandial availability of lysine following ingestion of proteins with a high glycation level may compromise the anabolic properties of a protein source.
We assessed the effects of increased Ca consumption from fat-free milk in an energy-restricted diet and educational activities in the metabolic control of overweight type 2 diabetes mellitus (T2DM) patients. Fourteen subjects with T2DM (BMI 29·4 (sd 4·5) kg/m2, low habitual Ca consumption (<600 mg/d)) were included in this randomised, crossover clinical trial. Subjects were randomly allocated to one of the two interventions: drink containing 700 mg of Ca (DAIR) or drink containing 0 mg of Ca (CONT) for ninety consecutive days each. Energy-restricted diets (–500 kcal/d; –2092 kJ/d), containing 800 mg of Ca from dietary sources/d, were prescribed for both groups. Questionnaires were applied at baseline and at the end of the study to assess the subjects’ knowledge on the disease and on self-care, biochemical variables and physical activity. Blood pressure, food intake, body composition and anthropometry were assessed at baseline, days 45 and 90. There was a higher reduction of body fat %, waist circumference, hip circumference, neck circumference, waist:hip ratio, sagittal abdominal diameter, diastolic/systolic blood pressure and an increase in fat-free mass % in DAIR than in CONT. Uric acid, fasting glucose, Hb1Ac, parathyroid hormone and alanine aminotransferase concentrations reduced and vitamin D concentration increased after 90 d in DAIR compared with CONT. The consumption of energy-restricted diet containing 1200 mg Ca/d seems to favour metabolic control in subjects with T2DM. The educational activities increased the knowledge on the disease care.
Prior data on long-term association between legume consumption and hypertension risk are sparse. We aimed to evaluate whether total legume and subtype intakes prospectively associate with hypertension incidence among 8758 participants (≥30 years) from the China Health and Nutrition Survey 2004–2011. Diet was assessed by interviews combining 3-d 24-h food recalls and household food inventory weighing at each survey round. Incident hypertension was identified by self-reports or blood pressure measurements. We applied multivariable Cox regressions to estimate hazard ratios (HR) with corresponding 95 % CI for hypertension across increasing categories of cumulatively averaged legume intakes. For 35 990 person-years (median 6·0 years apiece), we documented 944 hypertension cases. After covariate adjustment, higher total legume intakes were significantly associated with lower hypertension risks, with HR comparing extreme categories being 0·56 (95 % CI 0·43, 0·71; Ptrend < 0·001). Then we found that intakes of dried legumes (HR 0·53 (95 % CI 0·43, 0·65); Ptrend < 0·001) and fresh legumes (HR 0·67 (95 % CI 0·55, 0·81); Ptrend < 0·001) were both related to decreased hypertension hazards. However, further dried legume classification revealed that negative association with hypertension substantially held for soyabean (HR 0·51 (95 % CI 0·41, 0·62); Ptrend < 0·001) but not non-soyabean intakes. In stratified analyses, the association of interest remained similar within strata by sex, BMI, physical activity, smoking and drinking status; rather, significant heterogeneity showed across age strata (Pinteraction = 0·02). Total legume consumption among the over-65s was related to a more markedly reduced hypertension risk (HR 0·47 (95 % CI 0·30, 0·73); Ptrend < 0·001). Our findings suggest an inverse association of all kinds of legume (except non-soyabean) intakes with hypertension risks.
Excessive Ca intakes have been proposed to associate with vascular calcification and a higher risk of prostate cancer. We investigated the associations of supplemental and dietary Ca intake with mortality using data from 497 828 UK Biobank participants. The average follow-up was 4·2 years and 14 255 participants died, 8297 from cancer, 2959 from CVD and 572 from respiratory disease. The use of Ca supplements and milk consumption were associated with differences in mortality in younger (≤65 years) but not in older participants (>65 years, Pinteraction ≤ 0·04 for all comparisons). Among participants <65 years, there was an inverse association between Ca supplementation (OR 0·91, 95 % CI 0·83, 0·99) and milk consumption (OR 0·93, 95 % CI 0·86, 1·00) with respect to all-cause mortality. In the same age group, milk drinkers had lower odds of cancer mortality (OR 0·89, 95 % CI 0·80, 0·98) but Ca supplement use was associated with increased odds of respiratory mortality (OR 1·69, 95 % CI 1·16, 2·74). All associations in participants aged ≥65 years were null after full adjustment. In sensitivity analyses stratified by hormone replacement therapy, Ca supplement use was associated with decreased odds of cancer mortality in users but increased risk in other women (OR 0·81, 95 % CI 0·69, 0·94 v. OR 1·17, 95 % CI 1·01, 1·35, respectively). To conclude, we saw little evidence for harm with dietary or supplemental Ca. Further studies are required to confirm the proposed interaction with hormone replacement therapy and to exclude reverse causation as a determinant in the association between Ca supplements and increased risk of respiratory diseases.
Metabolically healthy obesity refers to a subset of obese people with a normal metabolic profile. We aimed to explore the association between metabolically healthy and obesity status and risk of hypertension among Chinese adults from The Rural Chinese Cohort Study. This prospective cohort study enrolled 9137 Chinese adults without hypertension, type 2 diabetes or treatment for lipid abnormality at baseline (2007–2008) and followed up during 2013–2014. Modified Poisson regression models were used to examine the risk of hypertension by different metabolically healthy and obesity status, estimating relative risks (RR) and 95 % CI. During 6 years of follow-up, we identified 1734 new hypertension cases (721 men). After adjusting for age, sex, smoking and other confounding factors, risk of hypertension was increased with metabolically healthy general obesity (MHGO) defined by BMI (RR 1·75, 95 % CI 1·02, 3·00) and metabolically healthy abdominal obesity (MHAO) defined by waist circumference (RR 1·51, 95 % CI 1·12, 2·04) as compared with metabolically healthy non-obesity. The associations between metabolically healthy and obesity status and hypertension outcome were consistent after stratifying by sex, age, smoking, alcohol drinking and physical activity. Both MHGO and MHAO were associated with increased risk of hypertension. Obesity control programmes should be implemented to prevent or delay the development of hypertension in rural China.
Exercise modifies energy intake (EI) in adolescents with obesity, but whether this is mediated by the exercise-induced energy deficit remains unknown. The present study examined the effect of exercise with and without dietary replacement of the exercise energy expenditure on appetite, EI and food reward in adolescents with obesity. Fourteen 12–15-year-old adolescents with obesity (eight girls; Tanner 3–4; BMI 34·8 (sd 5·7) kg/m2; BMI z score 2·3 (sd 0·4)) randomly completed three experimental conditions: (i) rest control (CON); (ii) 30-min cycling (EX) and (iii) 30-min cycling with dietary energy replacement (EX + R). Ad libitum EI was assessed at lunch and dinner, and food reward (Leeds Food Preference Questionnaire) before and after lunch. Appetite was assessed at regular intervals. Lunch, evening and total EI (excluding the post-exercise snack in EX − R) were similar across conditions. Lunch and total EI including the post-exercise snack in EX + R were higher in EX − R than CON and EX; EX and CON were similar. Total relative EI was lower in EX (6284 (sd 2042) kJ) compared with CON (7167 (sd 2218) kJ; P < 0·05) and higher in EX + R (7736 (sd 2033) kJ) compared with CON (P < 0·001). Appetite and satiety quotients did not differ across conditions (P ≥ 0·10). Pre-meal explicit liking for fat was lower in EX compared with CON and EX + R (P = 0·05). There was time by condition interaction between EX and CON for explicit wanting and liking for fat (P = 0·01). Despite similar appetite and EI, adolescents with obesity do not adapt their post-exercise food intake to account for immediate dietary replacement of the exercise-induced energy deficit, favouring a short-term positive energy balance.