Project description:Diet is a key lifestyle component that influences metabolic health through several factors, including total energy intake and macronutrient composition. While the impact of caloric intake on gene expression and physiological phenomena in various tissues is well described, the influence of dietary macronutrient composition on these parameters is less well studied. Here, we use the Nutritional Geometry framework to investigate the role of macronutrient composition on metabolic function and gene regulation in adipose tissue. Using ten isocaloric diets that vary systematically in their proportion of energy from fat, protein, and carbohydrates, we find that gene expression and splicing are highly responsive to macronutrient composition, with distinct sets of genes regulated by different macronutrient interactions. Specifically, the expression of many genes associated with Bardet-Biedl syndrome is responsive to dietary fat content. Splicing and expression changes occur in largely separate gene sets, highlighting distinct mechanisms by which dietary composition influences the transcriptome and emphasizing the importance of considering splicing changes to more fully capture the gene regulation response to environmental changes such as diet. Our study provides insight into the gene regulation plasticity of adipose tissue in response to macronutrient composition, beyond the already well-characterized response to caloric intake.
Project description:BackgroundUrban areas in central Asia are currently undergoing nutrition transition. Street food is very popular, but the specific foods available and their nutritional composition are unknown. The aim was to describe the availability and macronutrient composition of street foods in Bishkek, Kyrgyzstan.ResultsTrained interviewers collected data on street food vending sites' characteristics and food availability (n = 596). Samples of the most commonly available foods and drinks were collected (n = 80 homemade; n = 40 industrial). Macronutrients were quantified through chemical analysis. Fruit, beverages, and food other than fruit were available in 4.0%, 61.7%, and 81.0% of the vending sites, respectively. Among those selling food other than fruit, 56.5% sold only homemade (e.g., bread, main dishes, snacks, pastries, sandwiches, and cakes), 23.3% both homemade and industrial and 20.2% only industrial foods (e.g., bread, snacks, pastries, cakes, and cookies). Homemade foods presented the highest energy/serving (median kcal/serving: 357 versus 145, p < .001). A high content in saturated and trans-fatty acids was observed in some homemade traditional dishes and snacks, reaching, respectively, 30.2 g/serving and 2.9 g/serving (in homemade manty, a traditional dish). Tea and soft drinks were available in over 50% of the vending sites selling beverages.ConclusionThe high availability of street food in Bishkek highlights its importance for this urban population. Traditional snacks, dishes, and beverages coexist with more westernized products. The variability in energy, macronutrients, and lipid profile of homemade and industrial products reflects heterogeneous culinary practices and ingredients. Policies promoting the availability of healthy foods and ingredients should be implemented.
Project description:BackgroundAltering dietary carbohydrate or fat content may have chronic effects on insulin secretion and sensitivity, which may vary with individual metabolic phenotype.ObjectiveThe objective was to evaluate the contribution of tightly controlled diets differing in carbohydrate and fat content for 8 wk to insulin sensitivity and β cell responsiveness and whether effects of diet would vary with race, free-living diet, or insulin response.DesignHealthy overweight men and women (36 European Americans, 33 African Americans) were provided with food for 8 wk and received either a eucaloric standard diet (55% carbohydrate, 27% fat) or a eucaloric reduced-carbohydrate (RedCHO)/higher-fat diet (43% carbohydrate, 39% fat). Insulin sensitivity and β cell responsiveness were assessed at baseline and 8 wk by using a liquid meal tolerance test.ResultsInsulin sensitivity did not change with diet (P = 0.1601). Static β cell response to glucose (ФS) was 28.5% lower after the RedCHO/higher-fat diet. Subgroup analyses indicated that lower ФS with the RedCHO/higher-fat diet occurred primarily among African Americans. A significant inverse association was observed for change in glucose area under the curve compared with change in ФS.ConclusionsConsumption of a eucaloric 43% carbohydrate/39% fat diet for 8 wk resulted in down-regulation of β cell responsiveness, which was influenced by baseline phenotypic characteristics. Further study is needed to probe the potential cause-and-effect relation between change in ФS and change in glucose tolerance. This trial is registered at clinicaltrials.gov as NCT00726908.
Project description:BackgroundThe first stage of alcoholic liver disease is hepatic steatosis. While alcohol is known to profoundly impact hepatic lipid metabolism, gaps in our knowledge remain regarding the mechanisms leading to alcohol-induced hepatic triglyceride (TG) accumulation. As the sole enzymes catalyzing the final step in TG synthesis, diacylglycerol O-acyltransferase (DGAT) 1 and 2 are potentially important contributors to alcoholic steatosis. Our goal was to study the effects of dietary fat content on alcohol-induced hepatic TG accumulation, and the relative contribution of DGAT1 and DGAT2 to alcoholic steatosis.MethodsThese studies were carried out in wild-type (WT) mice fed alcohol-containing high-fat or low-fat formulations of Lieber-DeCarli liquid diets, as well as follow-up studies in Dgat1-/- mice.ResultsA direct comparison of the low-fat and high-fat liquid diet in WT mice revealed surprisingly similar levels of alcoholic steatosis, although there were underlying differences in the pattern of hepatic lipid accumulation and expression of genes involved in hepatic lipid metabolism. Follow-up studies in Dgat1-/- mice revealed that these animals are protected from alcoholic steatosis when consumed as part of a high-fat diet, but not a low-fat diet.ConclusionsDietary macronutrient composition influences the relative contribution of DGAT1 and DGAT2 to alcoholic steatosis, such that in the context of alcohol and a high-fat diet, DGAT1 predominates.
Project description:BackgroundThe Dietary Approaches to Stop Hypertension (DASH) diet pattern has shown some promise for preventing heart failure (HF), but studies have been conflicting.ObjectiveTo determine whether the DASH diet pattern was associated with incident HF in a large biracial and geographically diverse population.Methods and resultsAmong participants in the REasons for Geographic And Racial Differences in Stroke (REGARDS) cohort study of adults aged ≥45 years who were free of suspected HF at baseline in 2003-2007, the DASH diet score was derived from the baseline food frequency questionnaire. The main outcome was incident HF defined as the first adjudicated HF hospitalization or HF death through December 31, 2016. We estimated hazard ratios for the associations of DASH diet score quartiles with incident HF, and incident HF with reduced ejection fraction and HF with preserved ejection fraction using the Lunn-McNeil extension to the Cox model. We tested for several prespecified interactions, including with age. Compared with the lowest quartile, individuals in the second to fourth DASH diet score quartiles had a lower risk for incident HF after adjustment for sociodemographic and health characteristics: quartile 2 hazard ratio, 0.69 (95% confidence interval [CI], 0.56-0.85); quartile 3 hazard ratio, 0.71 (95% CI, 0.58-0.87); and quartile 4 hazard ratio, 0.73 (95% CI, 0.58-0.92). When stratifying results by age, quartiles 2-4 had a lower hazard for incident HF among those age <65 years, quartiles 3-4 had a lower hazard among those age 65-74, and the quartiles had similar hazard among those age ≥75 years (Pinteraction = .003). We did not find a difference in the association of DASH diet with incident HF with reduced ejection fraction vs HF with preserved ejection fraction (P = .11).ConclusionsDASH diet adherence was inversely associated with incident HF, specifically among individuals <75 years old.
Project description:Carbohydrate response element binding protein (ChREBP) is a lipogenic transcription factor that is thought to be involved in the development of hepatic steatosis and insulin resistance. Increased ChREBP expression in liver results in increased hepatic steatosis, and the isoform ChREBPβ in adipose tissue can predict insulin sensitivity in obese humans. As ChREBP is activated by glucose, it was postulated that the composition of diet would regulate ChREBP isoform expression in metabolically relevant tissues. We compared the effects of diets with high complex carbohydrate, high fat, or a normal chow on ChREBP expression and metabolic parameters in C57BL/6 mice. We found that diets high in fat decrease ChREBP expression in adipose tissue, but isocaloric diets high in carbohydrate have no effect. Interestingly, this decrease in adipose ChREBP was associated with increased inflammatory markers. In the same animals a high carbohydrate diet induced a robust increase in hepatic ChREBPβ expression (≈2-fold; p = 0.0002), but little detectable change in the more abundant ChREBPα transcript. This change was accompanied by increased expression of target genes liver pyruvate kinase (p<0.0001), acetyl-CoA carboxylase (p = 0.0191) and stearoyl-CoA desaturase-1 (p = 0.0045). This increase in ChREBP expression was associated with increased hepatic steatosis, despite no changes in body weight or body fat when compared to chow-fed mice. Unexpectedly, mice fed a high carbohydrate diet displayed enhanced sensitivity to exogenous insulin, despite having mild glucose intolerance and increased liver steatosis. In summary, we have shown the composition of diet can selectively regulate ChREBP isoform expression in a tissue specific manner. Furthermore, we have shown a high complex carbohydrate diet selectively increases hepatic ChREBPβ expression, which associates with hepatic steatosis but not insulin resistance. In contrast, a high fat diet reduces adipose ChREBP, which associates with inflammation and insulin resistance.
Project description:Glycaemic index (GI) is used as an indicator to guide consumers in making healthier food choices. We compared the GI, insulin index (II), and the area under the curve for blood glucose and insulin as glucose (GR) and insulin responses (IR) of a newly developed liquid nutritional formula with one commercially available liquid product with different types of carbohydrates. We then evaluated the glucose and insulin responses of two test foods with comparable energy density and protein percentage but presented in different food forms (liquid vs. solid). Fourteen healthy women participated in the study. GI, II, GR, and IR were assessed after (independent) consumption of two liquid products and a solid breakfast meal. The two liquid foods showed comparable GI, whilst the liquid form appeared to produce lower median GI (25 vs. 54), and II (52 vs. 98) values compared to the solid breakfast (p < 0.02). The median GR and IR for solid breakfast were respectively 44% and 45% higher compared to the liquid product (p < 0.02). Liquid formulas with different carbohydrate qualities produced comparable glucose responses, while foods with comparable energy density and protein percentage but different food form elicited differential effects on GI, II, GR, and IR. Nutrient quality and food form need to be taken into consideration when developing low GI products to manage glycaemic responses.
Project description:Food choice, in animals, has been known to change with internal nutritional state and also with variable dietary conditions. To better characterize mechanisms of diet-induced plasticity of food preference in Drosophila melanogaster, we synthesized diets with macronutrient imbalances and examined how food choice and taste sensitivity were modified in flies that fed on these diets. We found that dietary macronutrient imbalances caused compensatory behavioral shifts in both sexes to increase preference for the macronutrient that was scant in the food source, and simultaneously reduce preference for the macronutrient that was enriched. Further analysis with females revealed analogous changes in sweet taste responses in labellar neurons, with increased sensitivity on sugar-reduced diet and decreased sensitivity on sugar-enriched diet. Interestingly, we found differences in the onset of changes in taste sensitivity and behavior, which occur over 1-4 d, in response to dietary sugar reduction or enrichment. To investigate molecular mechanisms responsible for diet-induced taste modulation, we used candidate gene and transcriptome analyses. Our results indicate that signaling via Dop2R is involved in increasing cellular and behavioral sensitivity to sugar as well as in decreasing behavioral sensitivity to amino acids on dietary sugar reduction. On the other hand, cellular and behavioral sensitivity to sugar relies on dilp5 and a decrease in sugar preference following dietary sugar abundance was correlated with downregulation of dilp5 Together, our results suggest that feeding preference for sugar and amino acid can be modulated independently to facilitate food choice that accounts for prior dietary experience.SIGNIFICANCE STATEMENT Animals adjust their feeding preferences based on prior dietary experiences. Here, we find that upon dietary macronutrient deprivation, flies undergo compensatory changes in food preference. The altered preference correlates with changes in peripheral taste sensitivity. While Dop2R mediates changes following dietary sugar reduction, downregulation of dilp5 is associated with changes caused by a sugar-enriched diet. This study contributes to a better understanding of neurophysiological plasticity of the taste system in flies, and its role in facilitating adjustment of foraging behavior based on nutritional requirements.
Project description:Pulmonary hypertension (PH) is traditionally defined as a mean pulmonary arterial pressure (mPAP) ≥25 mmHg. Although various factors cause PH, the most common etiology is PH due to left heart disease (PH-LHD). The underlying LHD is characterized by heart failure (HF) with reduced ejection fraction (HFrEF), HF with preserved ejection fraction (HFpEF), valvular heart disease, cardiomyopathies, or arrhythmic diseases. Regardless of its underlying cause, elevated left atrial (LA) filling pressure is a manifestation of advanced heart disease. High LA pressure then causes persistent backflow to the pulmonary veins, which increases mPAP. PH-LHD at this stage is named isolated postcapillary PH (IpcPH). Further progression of IpcPH is associated with pulmonary vasculature remodeling and hypertrophy, which consists of adding the precapillary component of PH to the pre-existing postcapillary PH. This form of PH-LHD is called combined precapillary and postcapillary PH (CpcPH). To date, therapeutic strategies for PH-LHD have been investigated in the context of HFrEF or HFpEF. Pulmonary arterial hypertension (PAH)-specific drugs have been tested in HFrEF and HFpEF populations, although encouraging results have not been demonstrated. As PAH-specific drugs target the precapillary component of PH-LHD, future studies utilizing such therapeutics in PH-LHD patients with CpcPH appear to have a more robust pathobiological basis. This article reviews the diagnosis, pathophysiology, treatment, and future direction of PH in HF.
Project description:Diets rich in fats and carbohydrates aggravate non-alcoholic fatty liver disease (NAFLD), of which mitochondrial dysfunction is a central feature. It is not clear whether a high-carbohydrate driven 'lipogenic' diet differentially affects mitochondrial oxidative remodeling compared to a high-fat driven 'oxidative' environment. We hypothesized that the high-fat driven 'oxidative' environment will chronically sustain mitochondrial oxidative function, hastening metabolic dysfunction during NAFLD. Mice (C57BL/6NJ) were reared on a low-fat (LF; 10% fat calories), high-fat (HF; 60% fat calories), or high-fructose/high-fat (HFr/HF; 25% fat and 34.9% fructose calories) diet for 10 weeks. De novo lipogenesis was determined by measuring the incorporation of deuterium from D2O into newly synthesized liver lipids using nuclear magnetic resonance (NMR) spectroscopy. Hepatic mitochondrial metabolism was profiled under fed and fasted states by the incubation of isolated mitochondria with [13C3]pyruvate, targeted metabolomics of tricarboxylic acid (TCA) cycle intermediates, estimates of oxidative phosphorylation (OXPHOS), and hepatic gene and protein expression. De novo lipogenesis was higher in the HFr/HF mice compared to their HF counterparts. Contrary to our expectations, hepatic oxidative function after fasting was induced in the HFr/HF group. This differential induction of mitochondrial oxidative function by the high fructose-driven 'lipogenic' environment could influence the progressive severity of hepatic insulin resistance.