Nutrition & Metabolism - Latest Articles

Using 3-6 differences in essential fatty acids rather than 3/6 ratios gives useful food balance scores

Bill Lands — 2012-05-24T00:00:00Z

Background: The vitamin-like omega-3 and omega-6 essential fatty acids are converted in the body to alarge family of hormones which act at selective receptors that occur on nearly every cell andtissue. A relative omega-3 deficit allows overabundant actions of omega-6 hormones todevelop into health disorders. People need simple, explicit information on the balance ofessential fatty acids in their foods to avoid accumulating unintended imbalances in theirtissue omega-3 and omega-6 fatty acids. Results: We developed an Omega 3-6 Balance Food Score that summarizes in a single value thebalance among eleven omega-3 and omega-6 essential fatty acids in a food. The value allowsa quantitative estimate of the impact of each food item on the proportions of omega-3 andomega-6 that will accumulate in the 20- and 22-carbon highly unsaturated fatty acids ofblood, which is an important health risk assessment biomarker. Conclusions: The impact of an individual food item upon a useful health risk assessment biomarker iseasily evident in a simple, explicit value for the balance among eleven essential fatty acidsnutrients. Foods with more positive Omega 3-6 Balance Food Scores will increase thepercent of omega-3 in the biomarker, whereas those with more negative Scores will increasethe percent of omega-6 in the biomarker.

Transcriptome-based identification of antioxidative gene expression after fish oil supplementation in normo- and dyslipidemic men

Simone Schmidt — 2012-05-23T00:00:00Z

Background: The beneficial effects of omega-3 polyunsaturated fatty acids (n-3 PUFAs), especially indyslipidemic subjects with a high risk of cardiovascular disease, are widely described in theliterature. A lot of effects of n-3 PUFAs and their oxidized metabolites are triggered byregulating the expression of genes. Currently, it is uncertain if the administration of n-3PUFAs results in different expression changes of genes related to antioxidative mechanismsin normo- and dyslipidemic subjects, which may partly explain their cardioprotective effects.The aim of this study was to investigate the effects of n-3 PUFA supplementation onexpression changes of genes involved in oxidative processes. Methods: Ten normo- and ten dyslipidemic men were supplemented for twelve weeks with fish oilcapsules, each providing 1.5 g docosahexaenoic acid and 1.0 g eicosapentaenoic acid. Geneexpression levels were determined by whole genome microarray analysis and quantitativereal-time polymerase chain reaction (qRT-PCR). Results: Using microarrays, we discovered an increased expression of antioxidative enzymes and adecreased expression of pro-oxidative and tissue enzymes, such as cytochrome P450 enzymesand matrix metalloproteinases, in both normo- and dyslipidemic men. An up-regulation ofcatalase and heme oxigenase 2 in both normo- and dyslipidemic subjects and an upregulationof cytochrome P450 enzyme 1A2 only in dyslipidemic subjects could be observedby qRT-PCR analysis. Conclusions: Supplementation of normo- and dyslipidemic subjects with n-3 PUFAs changed theexpression of genes related to oxidative processes, which may suggest antioxidative andpotential cardioprotective effects of n-3 PUFAs. Further studies combining genetic andmetabolic endpoints are needed to verify the regulative effects of n-3 PUFAs in antioxidativegene expression to better understand their beneficial effects in health and disease prevention.Trial registrationClinicalTrials.gov (ID: NCT01089231)

Thyroid stimulating hormone, independent of thyroid hormone, can elevate the serum total cholesterol level in patients with coronary heart disease: a cross-sectional design

Chao Xu — 2012-05-23T00:00:00Z

Background: The relationship between TSH and the lipid profile is contradictory because few studies haveexcluded the potential influence of the thyroid hormones (TH). The aim of the present studywas to evaluate the relationship between serum TSH levels and the lipid profile independentof TH. Methods: 1302 CHD patients diagnosed by coronary angiography were retrospectively studied. Theprevalence and distribution of thyroid dysfunction were analyzed first. To assess the impactof TSH on serum lipids, Pearson's correlation analysis was performed after adjustments forclassic factors and TH. To calculate the extent of the effect of TSH on the serum cholesterollevel, the partial least squares method and additional statistical methods were used. Results: After the exclusions, a total of 568 patients (270 males and 298 females with a mean age of63.56 +/- 11.376 years) were selected. The prevalence of thyroid dysfunction among thepatients was 18.66%, and the prevalence of hypothyroidism (15.32%) was higher than that ofhyperthyroidism (3.34%). Even after adjusting for confounding factors, such as sex, age,smoking status, fasting plasma glucose levels and TH, a significant positive impact of TSHon the serum total cholesterol (TC) level was revealed (r = 0.095, p = 0.036). Each 1 mIU/Lincrease in the TSH level was linked to a 0.015580712 mmol/L elevation of the serum TCvalue. Conclusions: TSH can increase the TC level in CHD patients independent of TH. The present studysuggests a potential physiological role of TSH and the importance of maintaining anappropriate TSH level in CHD patients.

Effect of a LoBAG30 diet on protein metabolism in men with type 2 diabetes

Frank Nuttall — 2012-05-20T00:00:00Z

Background: We previously reported that a weight-maintenance diet with a carbohydrate:protein:fat ratio of 30:30:40%, ingested for 5 weeks, improved blood glucose control in subjects with untreated type 2 diabetes. In this study we also determined that insulin and insulin-like growth factor-I (IGF-I) were increased. In this report we provide further information. Specifically, 24-hour total and individual amino acid, glucagon and cortisol data are provided. In addition, we determined whether these multiple effectors resulted in a positive nitrogen balance and an increase in fat-free mass. Insulin and IGF-I should stimulate protein accumulation. An increase in amino acids, particularly branched chain amino acids should facilitate this, whereas glucagon and cortisol could have adverse effects in this regard. Methods: Eight men with untreated type 2 diabetes were studied. A randomized crossover design was used. Data were obtained before and after 5 weeks on a control diet (55% carbohydrate:15% protein:30% fat) and the 30% carbohydrate:30% protein:40% fat diet. Nitrogen balance and body composition were determined at the beginning and end of each dietary intervention. Results: As expected, the mean 24-hour total amino acid area response was higher after ingesting the 30:30:40 diet. However, the increase was only statistically significant for the branched chain amino acids, and phenylalanine and tyrosine. The 24-hour cortisol profile was unchanged. Glucagon was increased. Nitrogen balance was positive. Body weight was stable. Body composition and computed tomography data indicate no change in the fat-free mass had occurred. Conclusion: This high protein, low carbohydrate diet induced a metabolic milieu which strongly favors a positive protein balance, and a positive balance was present. However, an increase in lean (protein) mass was not documented. Whether such a diet in people with type 2 diabetes is useful in preventing or delaying the loss of total lean body mass and/or sarcopenia associated with aging remains to be determined.

Serum 25-hydroxyvitamin D3 and body composition in an elderly cohort from Germany: a cross-sectional study

Alexandra Jungert — 2012-05-18T00:00:00Z

Background: Emerging evidence indicates that there is an association between vitamin D and obesity. The aim of this study was to investigate whether the level of serum 25-hydroxyvitamin D3 [25(OH)D3] in the elderly is influenced by parameters of anthropometry and body composition independent of potential confounding lifestyle factors and the level of serum intact parathyroid hormone (iPTH). Methods: Cross-sectional data of 131 independently living participants (90 women, 41 men; aged 66-96 years) of the longitudinal study on nutrition and health status in senior citizens of Giessen, Germany were analysed. Concentrations of 25(OH)D3 and iPTH were ascertained by an electrochemiluminescence immunoassay. Body composition was measured by a bioelectrical impedance analysis. We performed univariate and multiple regression analyses to examine the influence of body composition on 25(OH)D3 with adjustments for age, iPTH and lifestyle factors. Results: In univariate regression analyses, 25(OH)D3 was associated with body mass index (BMI), hip circumference and total body fat (TBF) in women, but not in men. Using multiple regression analyses, TBF was shown to be a negative predictor of 25(OH)D3 levels in women even after controlling for age, lifestyle and iPTH (SZ = -0.247; P = 0.016), whereas the associations between BMI, hip circumference and 25(OH)D3 lost statistical significance after adjusting for iPTH. In men, 25(OH)D3 was not affected by anthropometric or body composition variables. Conclusions: The results indicate that 25(OH)D3 levels are affected by TBF, especially in elderly women, independent of lifestyle factors and iPTH.

Vitamin B12 deficiency in the brain leads to DNA hypomethylation in the TCblR/CD320 knockout mouse.

Edward Quadros — 2012-05-18T00:00:00Z

Vitamin B12 deficiency in the brain leads to DNA hypomethylation in the TCblR/CD320 knockout mouse.Authors: Silvia Fernandez-Roig1, Shao-Chiang Lai2, Michelle M Murphy1, Joan Fernandez-Ballart1, Edward V Quadros2*.Institutional addresses:1Area of Preventive Medicine and Public Health, Faculty of Medicine and Health Sciences, Universitat Rovira i Virgili (URV), IISPV, Reus, Spain and CIBER Fisiopatologia de la Obesidad y Nutricion (CB06/03) Instituto Carlos III.2Departments of Medicine and Cell Biology, SUNY Downstate Medical Center, Brooklyn,New York, USA.Email address for all authors:silvia.fernandez@urv.cat ;shao-chiang.lai@downstate.edumichelle.murphy@urv.cat;joan.fernandez-ballart@urv.cat ;edward.quadros@downstate.edu.*Corresponding author:Prof. Edward V Quadros,Department of Medicine,SUNY Downstate Medical Center,Brooklyn, New York, USA.Abstract Background: DNA methylation is an epigenetic phenomenon that can modulate gene function by up or downregulation of gene expression. Vitamin B12 and folate pathways are involved in the production of S-Adenosylmethionine, the universal methyl donor.FindingsBrain vitamin B12 concentration and global DNA methylation was determined in transcobalamin receptor (TCblR/CD320) knock out (KO) (n=4) and control mice (n=4) at 20-24 weeks of age. Median [IQR] brain vitamin B12 concentrations (pg/mg) in TCblR/CD320 KO mice compared with control mice was 8.59 [0.52] vs 112.42 [33.12]; p<0.05. Global DNA methylation levels in brain genomic DNA were lower in TCblR/CD320 KO compared with control mice (Median [IQR]: 0.31[0.16] % vs 0.55[0.15] %; p<0.05.). Conclusions: In TCblR/CD320 KO mice, brain vitamin B12 drops precipitously by as much as 90% during a 20 week period. This decrease is associated with a 40% decrease in global DNA methylation in the brain. Future research will reveal whether the disruption in gene expression profiles due to changes in DNA hypomethylation contribute to central nervous system pathologies that are frequently seen in vitamin B12 deficiency.

Nutritional regulation of muscle protein synthesis with resistance exercise: strategies to enhance anabolism

Tyler Churchward - Venne — 2012-05-17T00:00:00Z

Provision of dietary amino acids increases skeletal muscle protein synthesis (MPS), an effectthat is enhanced by prior resistance exercise. As a fundamentally necessary process in theenhancement of muscle mass, strategies to enhance rates of MPS would be beneficial in thedevelopment of interventions aimed at increasing skeletal muscle mass particularly whencombined with chronic resistance exercise. The purpose of this review article is to provide anupdate on current findings regarding the nutritional regulation of MPS and highlight nutritionbased strategies that may serve to maximize skeletal muscle protein anabolism withresistance exercise. Such factors include timing of protein intake, dietary protein type, therole of leucine as a key anabolic amino acid, and the impact of other macronutrients (i.e.carbohydrate) on the regulation of MPS after resistance exercise. We contend that nutritionalstrategies that serve to maximally stimulate MPS may be useful in the development ofnutrition and exercise based interventions aimed at enhancing skeletal muscle mass whichmay be of interest to elderly populations and to athletes.

Effects of combined maternal administration with alpha-ketoglutarate (AKG) and beta-hydroxy-beta- methylbutyrate (HMB) on prenatal programming of skeletal properties in the offspring

Marcin Tatara — 2012-05-11T00:00:00Z

Background: Nutritional manipulations during fetal growth may induce long-term metabolic effects inpostnatal life. The aim of the study was to test whether combined treatment of pregnant sowswith alpha-ketoglutarate and beta-hydroxy-beta-methylbutyrate induces additive long-term effectson skeletal system properties in the offspring. Methods: The study was performed on 290 pigs obtained from 24 sows divided into 4 equal groups andsubjected to experimental treatment during two weeks before delivery. The first groupconsisted of control sows, while the second group received alpha-ketoglutarate. The thirdgroup was treated with beta-hydroxy-beta-methylbutyrate and the fourth group underwentcombined administration of alpha-ketoglutarate and beta-hydroxy-beta-methylbutyrate. Pigletsobtained from sows were reared until slaughter age to perform morphometric, densitometricand mechanical analyses of femur. Serum evaluations of growth hormone, insulin-likegrowth factor-1, bone-specific alkaline phosphatase and osteocalcin were performed innewborns and 90-day old piglets; additionally, plasma amino acid concentration wasmeasured in newborns. Results: Maternal treatment with alpha-ketoglutarate and beta-hydroxy-beta-methylbutyrate significantlyreduced fattening time and increased birth body weight, daily body weight gain, bone weight,volumetric bone mineral density, geometrical parameters and mechanical endurance offemur. These effects were associated with increased serum concentrations of growthhormone, insulin-like growth factor-1, bone-specific alkaline phosphatase and osteocalcin.Furthermore, alpha-ketoglutarate and beta-hydroxy-beta-methylbutyrate administered solely or incombination significantly increased plasma level of 19 amino acids. Conclusions: Hormonal and amino acid evaluations in pigs indicate additive effects of AKG and HMB onsystemic growth and development; however, determination of bone properties has not shownsuch phenomenon.

Substrate utilization during submaximal exercise in children with a severely obese parent

Audrey Eaves — 2012-05-09T00:00:00Z

Background: We have reported a reduction in fatty acid oxidation (FAO) at the whole-body level and inskeletal muscle in severely obese (BMI [greater than or equal to] 40 kg/m2) individuals; this defect is retained in cellculture suggesting an inherent component. The purpose of the current study was to determineif an impairment in whole-body fatty acid oxidation (FAO) was also evident in children witha severely obese parent. Methods: Substrate utilization during submaximal exercise (cycle ergometer) was determined inchildren ages 8-12 y with a severely obese parent (OP, n = 13) or two lean/non-obese (BMIrange of 18 to 28 kg/m2) parents (LP, n = 13). A subgroup of subjects (n = 3/group)performed 4 weeks of exercise training with substrate utilization measured after theintervention. Results: The children did not differ in age (LP vs. OP, respectively) (10.7 +/- 0.5 vs. 10.2 +/- 0.5 y), BMIpercentile (65.3 +/- 5.2 vs. 75.9 +/- 7), Tanner Stage (1.4 +/- 0.2 vs. 1.5 +/- 0.2), VO2peak (40.3 +/-2.7 vs. 35.6 +/- 2.6 ml/kg/min) or physical activity levels (accelerometer). At the same absoluteworkload of 15 W (~38% VO2peak), RER was significantly (P [less than or equal to] 0.05) lower in LP vs. OP(0.83 +/- 0.02 vs. 0.87 +/- 0.01) which was reflected in a reduced reliance on FAO for energyproduction in the OP group (58.6 +/- 5.1 vs. 43.1 +/- 4.0% of energy needs during exercise fromFAO). At a higher exercise intensity (~65% VO2peak) there were no differences in substrateutilization between LP and OP. After exercise training RER tended to decrease (P = 0.06) atthe 15 W workload, suggesting an increased reliance on FAO regardless of group. Conclusions: These findings suggest that the decrement in FAO with severe obesity has an inherentcomponent that may be overcome with exercise training.

Meju, unsalted soybeans fermented with Bacillus subtilis and Aspergilus oryzae, potentiates insulinotropic actions and improves hepatic insulin sensitivity in diabetic rats

Hye Jeong Yang — 2012-05-02T00:00:00Z

Background: Although soybeans have the ability to attenuate insulin resistance, it is insufficient to alleviatetype 2 diabetic symptoms and different types of fermented soybeans may have even betteranti-diabetic effects. Meju, unsalted fermented soybeans exhibited better insulin sensitizingand insulinotropic actions than unfermented cooked soybeans (CSB). We investigatedwhether meju fermented in the traditional (TMS) manner for 60 days and meju fermented inthe standardized (MMS) method inoculating Bacillus subtilis and Aspergillus oryzae for 6days modulated insulin resistance, insulin secretion, and pancreatic beta-cell growth andsurvival in 90% pancreatectomized (Px) diabetic rats, a moderate and non-obese type 2diabetic animal model. Methods: Diabetic rats were divided into 3 groups: 1) TMS (n = 20), 2) MMS (n = 20) or 3) casein(control; n = 20). Rats were provided with a high fat diet (40 energy % fat) containingassigned 10% meju for 8 weeks. At the end of experiment insulin resistance and insulinsecretion capacity were measured by euglycemic hyperinsulinemic clamp and byhyperglycemic clamp, respectively. Additionally, beta-cell mass and islet morphohometry weredetermined by immunohistochemistry and insulin signaling in the liver was measured bywestern blot. Results: TMS and MMS increased isoflavonoid aglycones much more than CSB. CSB andTMS/MMS improved glucose tolerance in diabetic rats but the mechanism was differentbetween treatments (P < 0.05). CSB enhanced peripheral insulin sensitivity including hepaticinsulin sensitivity better than the control but TMS and MMS enhanced only hepatic insulinsensitivity through activating insulin signaling in diabetic rats (P < 0.05). However, TMS andMMS, but not CSB, potentiated glucose-stimulated insulin secretion and beta-cell mass (P <0.05). MMS had better insulinotropic actions than the control (P < 0.05). Conclusions: The anti-diabetic action of MMS, especially when fermented with Bacillus subtilis andAspergillus oryzae, was superior to CSB by increasing isoflavonoid aglycones and smallpeptides with regard to type 2 diabetic rats.