Increased Energy Intake Research Articles

Role of Taste Receptor Gene Variations (SNPs) on Diet Quality in Adolescent Females

The prevalence of pediatric obesity has increased over the past 40 years and the rate in females 6 to 19 years old is currently over 19%. This profound increase in obesity is predicted to negatively impact health and result in multiple obesity‐related comorbidities in adulthood. Obesity disproportionately affects ethnic minorities with a higher percentage of adolescent African‐American females (~29%) with obesity compared to non‐Hispanic, white females (~15%). The overconsumption of highly palatable, energy dense, foods are linked to obesity and single nucleotide polymorphisms (SNP) from taste genes are linked to alterations in taste perception and food choices. SNPs are associated with higher rates of obesity and altered fat perception (CD36; fat), higher caloric intake from sugar (TAS1R2; sweet) and increased energy intake (TAS2R38, bitter). An enhanced understanding of genetic, environmental, and behavioral factors contributing to excess weight in adolescents is paramount. Therefore, the goal of the current study was to investigate the intersection of genotype (rs1761667 of CD36 (AA), rs35874116 of TAS1R2 (TT) and rs713598 of TAS2R38 (CC)) and phenotype on diet intake and quality in adolescent African‐American and white females. Genotype was determined by allelic discrimination assay in females (10‐16 years old; n=142) enrolled in the Translational Investigation of Growth and Everyday Routines in Kids (TIGER Kids) Study. Anthropometrics and 24‐hour dietary recalls were conducted for each participant and Healthy Eating Index (HEI) scores, a measure of diet quality, were calculated. The effect of race and genetic variation was assessed using a two‐way ANOVA. Based on allelic discrimination assays, the expression rates of CD36 AA, TAS1R2 TT and TAS2R38 CC in white females (27.7%, 45.0%, 38.3%, respectively) and African‐American females (15.3%, 37.3%, 31.0%, respectively) were determined. Preliminary results indicated that BMI percentiles were higher in African‐American females across all genotypes (p<.05) and moderately affected by TAS2R38 genotype (p<.06). CD36 and race differentially affected HEI for added sugar, total vegetable, greens and beans, whole grain, seafood and plant protein and total HEI, (p<.05). TAS1R2 and race differentially affected HEI‐added sugar (p<.05). TAS2R38 significantly affected HEI‐sodium and total protein (p<.05) and TAS2R38 and race differentially affected HEI for total vegetables, fruits, and whole fruits (p<.09). Fat and sugar intake (g) were positively correlated with SNPs previously associated with altered fat perception (CD36 AA), sugar intake (TAS1R2 TT) and overall energy intake (TAS2R39 CC) in white (p<.05), but not African‐American females, suggesting that the effects of taste receptor SNPs on the relationship between fat and sugar intake differs by race. Overall, the results from these analyses support the intersection between race and genetic variation on HEI, and suggest that SNPs in taste receptor genes differently affect diet quality in adolescent females. Further understanding of the role of taste receptor SNPs on food choices and diet quality is needed to better tailor dietary interventions in the pediatric population.

Chronic Circadian Disruption and Sleep Restriction Influence Subjective Hunger, Appetite, and Food Preference.

Chronic circadian disruption (CCD), such as occurs during rotating shiftwork, and insufficient sleep are each independently associated with poor health outcomes, including obesity and glucose intolerance. A potential mechanism for poor health is increased energy intake (i.e., eating), particularly during the circadian night, when the physiological response to energy intake is altered. However, the contributions of CCD and insufficient sleep to subjective hunger, appetite, food preference, and appetitive hormones are not clear. To disentangle the influences of these factors, we studied seventeen healthy young adults in a 32-day in-laboratory study designed to distribute sleep, wakefulness, and energy intake equally across all phases of the circadian cycle, thereby imposing CCD. Participants were randomized to the Control (1:2 sleep:wake ratio, n = 8) or chronic sleep restriction (CSR, 1:3.3 sleep:wake ratio, n = 9) conditions. Throughout each waking episode the participants completed visual analog scales pertaining to hunger, appetite, and food preference. A fasting blood sample was collected to assess appetitive hormones. CCD was associated with a significant decrease in hunger and appetite in a multitude of domains in both the Control and CSR groups. This change in hunger was significantly correlated with changes in the ghrelin/leptin ratio. These findings further our understanding of the contributions of CCD and insufficient sleep on subjective hunger and appetite as well as of their possible contributions to adverse health behaviors.

The Effect of Dietary Fat and Sucrose on Cognitive Functioning in Mice Lacking Insulin Signaling in Neuropeptide Y Neurons.

Obesogenic diets can produce hippocampal insulin resistance and impairments to hippocampal-dependent cognition. This study investigated the effect of disrupted insulin signaling in Neuropeptide Y (NPY) neurons on diet-induced deficits in hippocampal-dependent memory. Wild-type mice and mice that had a targeted knockout of insulin receptors on NPY cells (IRlox/lox;NPYCre/+) were given ad libitum access to a high-fat diet (high fat; HF), 10% sucrose solution (high sugar; HS), both high-fat diet and sucrose solution (high fat, high sugar; HFHS), or a normal fat control chow for 12 weeks. Mice were tested in the Morris Water Maze (MWM), a hippocampal-dependent spatial memory task. Glucose homeostasis was assessed via a glucose tolerance test. Independent of genotype, consumption of HF, but not HS, diet increased energy intake, body weight, and plasma leptin, and impaired glucose tolerance. Disrupted insulin signaling in NPY cells and dietary interventions did not significantly affect the ability of mice to learn the location of the platform in the MWM. However, for IRlox/lox control mice, consumption of HF, but not HS, diet resulted in reduced time spent in the target quadrant during the probe trial, suggesting a hippocampal-dependent memory deficit. IRlox/lox;NPYCre/+ mice had poor performance in the probe trial regardless of diet, suggesting a floor effect. This study did not find adverse effects of chronic sucrose intake on metabolic outcomes or hippocampal-dependent memory. These data also suggest that the effects of HF diet on hippocampal-dependent memory may be dependent on insulin signaling in hippocampal NPY cells.

Sleep Deprivation: Effects on Weight Loss and Weight Loss Maintenance.

This narrative review presents the findings from intervention studies on the effects of sleep deprivation on eating habits, metabolic rate, and the hormones regulating metabolism, and discusses their relevance to weight loss efforts. Disturbed sleeping patterns lead to increased energy intake, partly from excessive snacking, mainly on foods high in fat and carbohydrates. The studies focused mainly on the effects of sleep duration, but also of sleep quality, on dietary intake during weight loss trials, and on weight loss maintenance. It is important to explore sleep routines that could enhance the efforts of obese and overweight people to lose weight, maintain their weight loss, and improve their overall health.

Meal timing across the day modulates daily energy intake in adult patients with type 2 diabetes.

We assessed the association between the timing of meals across the day with diet composition and metabolic parameters in patients with type-2 diabetes (T2D). Eighty adults (55.2 ± 6.8 years, 45% males) patients with T2D (without insulin therapy) were included. Three non-consecutive dietary records assessed food intake. The onset time of each consumed meal/beverage was identified and assigned to one of three periods of the day: Period 1 (P1, 06:00-11:59 h), Period 2 (P2, 12:00-17:59 h), and Period 3 (P3, 18:00-00:30 h). Energy intake in P1 was lower compared to P2 and P3 (22.8 ± 7.9%, 37.5 ± 9.6%, and 39.7 ± 9.9%, respectively, P < 0.001). The same pattern was found for both total protein and fat intake, but carbohydrate intake was similar among periods. Patients with greater daily energy intake (as % of total energy) in P3 showed increased total food consumption, total energy, protein, and fat intake (all P < 0.05). The opposite pattern was observed in patients with greater daily energy intake in P1 (all P < 0.05). Regression analysis showed that daily energy intake was significantly reduced when a higher proportion of carbohydrates was eaten in P1 (vs. P3, P < 0.04). Increased energy intake late during the day is related to increased total food and daily energy intake in patients with T2D. A greater proportion of total carbohydrates eaten early during the day relates to lower total energy intake. Our results suggest that earlier food intake may be a nutritional tool for dietary and metabolic control in these patients.

Relationship between Carotid-Femoral Pulse Wave Velocity and Diet-Induced Weight Loss

The global epidemic of obesity has increased over the past two decades, which has been attributed to a lack of physical activity and increased energy intake. Given the fact that obesity increases the risk of cardiovascular diseases, nutritional approaches to prevent cardiovascular diseases often target weight loss. Although many strategies are used to induce weight loss, the most common ones involve either total energy restriction, carbohydrate restriction, or dietary fat restriction. This report addresses the impact of each diet on improving carotid-femoral pulse wave velocity, a technique that is used to measure arterial stiffness—a surrogate marker of cardiovascular disease risk. Fourteen studies were included in the analysis and revealed that diet-induced weight-loss plateaus with increasing duration of the intervention (p = 0.174, r = 0.455). Weight loss was significantly associated with a reduction in cf-PWV (p = 0.012, r = 0.591). Further, when macronutrient composition was considered, weight loss was achieved through a low-carbohydrate diet (p = 0.097, r = 0.626), not total energy restriction (p = 0.660, r = 0.204) or low-fat diet (p = 0.142, r = 0.975), tended to reduce cf-PWV. These data suggest that weight loss achieved through a low-carbohydrate diet may have a greater impact on PWV over total energy restriction. More studies are needed to test the effect of weight loss achieved through a low-fat diet on cf-PWV.

Effect of maternal dietary starch-to-fat ratio and daily energy intake during late pregnancy on the performance and lipid metabolism of primiparous sows and newborn piglets.

The present study evaluated the effects of maternal dietary energy intake and starch-to-fat ratio during late gestation on the performance and lipid metabolism of sows and their offspring. On day 84 of gestation, 80 Landrace × Yorkshire primiparous sows were assigned to 2×2 factorial arrangements according to body weight following a randomized complete block design. The factors were daily energy intake (8,375 kcal ME/d [CE] vs. 9,600 kcal ME/d [HE]) and dietary starch-to-fat ratio (10:1 [CR] vs. 15:1 [HR]). All sows were fed one of four diets from day 85 of gestation until farrowing. Data were analyzed using the GLM procedure in SPSS. High energy intake increased the body weight of sows on day 110 of gestation (P = 0.031) as well as the weight of piglets at birth (P = 0.018). Increased energy intake elevated the plasma triglyceride concentrations in sows (P = 0.027) and piglets (P = 0.044). Maternal high energy intake altered the liver metabolome of newborn piglets in terms of metabolites related to carbohydrate and linoleic acid metabolism. Moreover, maternal high energy intake increased hepatic total cholesterol (P = 0.023) and triglyceride (P = 0.026) concentration in newborn piglets. Furthermore, maternal high energy intake significantly increased the transcript abundance of fatty acid synthase (FAS; P = 0.001) and protein abundance of phosphorylated protein kinase B (P =0.001) in the liver of newborn piglets. A high starch-to-fat ratio reduced low-density lipoprotein cholesterol (LDL-C) concentration in the plasma of sows (P = 0.044) and newborn piglets (P = 0.048) as well as in the liver of newborn piglets (P = 0.015). Furthermore, maternal high starch-to-fat ratio increased the transcript abundances of FAS (P = 0.004) in newborn piglets. In conclusion, high daily energy intake of sows increased the birth weight of newborn piglets. Moreover, maternal high daily energy intake and high dietary starch-to-fat ratio improved the lipid metabolism of newborn piglets.

Physician Compliance with Nutrition Support Team Recommendations: Effects on the Outcome of Treatment for Critically Ill Patients

Purpose: Attending physicians in Korea are aware of the existence of the Nutrition Support Team (NST), but even when the NST are consulted, compliance with their recommendations may be low. This study was performed to identify physicians’ compliance with the NST advice and how this affected the outcome of treatment for critically ill patients.Methods: This study was a retrospective observational study. Critically ill patients who were older than 18 years, younger than 90 years, and had been admitted and managed in the intensive care unit were selected for this study. Patients were assigned to either the compliance group or the non-compliance group according to physician compliance with the NST advice. Each group were compared using variables such as calorie supply, protein supply, laboratory findings, hospital stay, 30-day mortality, and survival rate.Results: The compliance group (81% of cases) was supplied with a significantly higher energy (1,146.36 ± 473.45 kcal vs. 832.45 ± 364.28 kcal, p < 0.01) and a significantly higher protein (55.00 ± 22.30 g/day vs. 42.98 ± 24.46 g/day, p = 0.04) compared with the non-compliance group. There was no significant difference in the basic demographics between groups, although the compliance group had a better outcome in the 30-day mortality rate (8% vs. 26%, p = 0.02), and in survival beyond 1 year (Crude model, hazard ratio: 2.42, CI: 1.11-5.29).Conclusion: Critically ill patients whose attending physician complied with the NST advice, received an increased energy intake and supply of protein which was positively associated with survival.

Moonlight drives nocturnal vertical flight dynamics in black swifts

Many animals have evolved a migratory lifestyle as an adaptation to seasonality,1,2 ranging from insects3 to fish,4 terrestrial and marine mammals,5-7 and birds.8 Old World swifts have evolved an extraordinary aerial non-breeding life phase lasting for 6-10 months.9-11 Swifts exploit the aerosphere in search of insects to meet the high energy demands of flight.12 During this period they roost and likely also sleep in the open airspace. Nocturnal insectivores with restricted foraging time may use moonlight to increase energy intake.13 Using multisensor data loggers that record light for geolocation, acceleration for flight activity, and pressure for flight altitude, we investigated if Northern black swifts, Cypseloides niger borealis, breeding in North America, also lead an aerial lifestyle similar to their Old World relatives. Individual flight activity showed they are airborne >99% of the time, with only occasional landings during their 8-month non-breeding period. Unexpectedly, during periods around the full moon, they conducted regular nocturnal ascents to altitudes up to >4,000 m (mean 2,000 m). A lunar eclipse triggered a synchronized descent, showing a direct effect of moonlight on flight altitude. This previously unknown behavior of nocturnal ascents during moonlight nights could be either a response to predator avoidance or that moonlight provides a foraging opportunity. Observed elevated nocturnal flight activity during periods of moonlight compared to dark nights suggests swifts were hawking for prey. Our finding of this novel behavior provides new perspectives on nocturnal flight behavior during periods surrounding the full moon.

The relation of dietary components with severity of obstructive sleep apnea in Cypriot patients: A randomized, stratified epidemiological study.

BackgroundObstructive Sleep Apnea (OSA) is considered a public health problem and its prevalence is increasing at an epidemic rate. The aim of this study was to examine whether individual nutrients (macronutrients, antioxidant vitamins) rather than energy restriction may potentially affect OSA severity in a representative population of Cyprus.MethodsA total sample of 303 adults (>18 years old) with Cypriot citizenship and permanently residing in Cyprus were randomly selected. Selected patients have completed the food frequency questionnaire, and a physical activity questionnaire and underwent a sleep study to assess OSA severity.ResultsOverall, 303 patients were included in this study, 169 (55.8%) had mild OSA (apnea-hypopnea index—AHI <15) and the remaining 83 (27.4%) had moderate to severe OSA (AHI>15). The mean age of all patients was 55.7 years old. Patients with moderate to severe OSA had significant higher BMI levels, higher consumption of calories, higher hip circumference, waist circumference, waist-hip ratio and neck circumference and higher consumption of folic acid compared with the patients with mild OSA (p<0.05).ConclusionsThe findings suggest that increased energy intake regardless diet macronutrient composition is positively associated with OSA severity whereas higher folic acid intake seems to have a protective role.

Changes in the liver transcriptome and physiological parameters of Japanese Black steers during the fattening period

We investigated the physiological changes during the fattening period and production characteristics in Japanese Black steers bred and raised using the typical feeding system in Japan. Here, 21 Japanese Black steers aged 12 months were used, with experimental period divided into early (12–14 months of age), middle (15–22 months), and late fattening phases (23–30 months). The liver transcriptome, blood metabolites, hormones, and rumen fermentation characteristics were analyzed. Blood triglyceride and non-esterified fatty acid concentrations increased, whereas blood ketone levels decreased, with fattening phases. Blood insulin increased with fattening phases and was positively correlated with carcass weight and marbling in late fattening phases. Rumen fermentation characteristics showed high propionate levels and low butyrate levels in late fattening phases, likely due to increased energy intake. Genes related to glucose metabolism, such as SESN3, INSR, LEPR, and FOXO3, were down-regulated in late fattening phases. Genes related to lipid metabolism, such as FABP4, were up-regulated, whereas FADS1 and FADS2 were down-regulated. These findings suggest that the physiological changes resulted from changes in the energy content and composition of diets. Liver metabolism changed with changes in fat metabolism. Insulin was strongly associated with physiological changes and productivity in Japanese Black cattle.

Dietary inclusion of ruminally protected linseed oil as a means to mitigate heat and slaughter-induced stress in feedlot cattle.

There is evidence of a relationship between increased energy intake and the development of metabolic inflammation and insulin resistance (IR), and between the aforementioned metabolic state and impaired tolerance to heat stress. Based on the anti-inflammatory properties and mitigating effects on IR and stress of n-3 polyunsaturated fatty acids (n-3 PUFA), an experiment was performed to evaluate the effect of n-3 PUFA supplementation to feedlot-finished steers during summer on animal performance, physiological and biochemical variables associated with glucose metabolism, heat and preslaughter-induced stress, and meat quality. A total of 48 Angus steers (388±2kg) were fed one of three corn-based finishing diets containing (dry matter basis) 0% added oil (CON; negative control), or 1.90% of sunflower oil-calcium salt (SUN; positive control), or 1.92% of linseed oil-calcium salt (LIN). There was a trend (P = 0.08) for greater dry matter intake (DMI) and greater (P = 0.02) average daily gain (ADG) in LIN-fed animals compared with the average between those that received the CON or SUN diets, whereas no differences (P ≥ 0.34) were observed between the latter. No other performance, physiological, or carcass variables were affected (P ≥ 0.12) by treatment. Blood glucose and insulin were similar (P ≥ 0.14), though the homeostatic model assessment (HOMA) which gauges IR tended (P = 0.06) to be reduced for LIN-fed animals compared with the average between those that received the CON or SUN diets. Blood insulin and HOMA increased linearly (P ≤ 0.01) with days on feed. An interaction between the study phase (feeding period or slaughter) and treatment was observed (P ≤ 0.05) for glucose and cortisol. While the magnitude of glucose increase (P < 0.01) from the end of the feeding period to slaughter was greater for CON- and SUN-fed animals compared with LIN-fed ones, cortisol increased (P < 0.05) only in animals that received CON or SUN diets. Meat quality attributes were not affected (P ≥ 0.16) by treatment. The concentration of n-3 PUFA was greater (P < 0.01) and n-6:n-3 ratio was lesser (P < 0.01) in meat from LIN-fed animals compared with that resulting from the average between the animals that received the negative (CON) or positive (SUN) control diets. Results suggest that n-3 PUFA supplementation mitigated metabolic alterations associated with IR and preslaughter-related stress. It may have also improved tolerance to heat, resulting in greater DMI and ADG of steers fed a high-energy diet during summer. Results also indicate that glucose metabolism and heat stress tolerance worsen with time when feeding concentrate-based diets.

Weight Gain Recommendations for Athletes and Military Personnel: a Critical Review of the Evidence.

Sports nutrition guidelines typically state that athletes desiring weight gain follow a regimen that includes increasing energy intake by ~ 300-500kcal/day with an emphasis on adequate protein and carbohydrate and judicious inclusion of energy-dense foods, in combination with rigorous resistance training. This regimen is thought to promote weekly gains of ~ 0.45kg (1lb), mostly as lean body mass (LBM). This review summarizes the evidence supporting these intentional weight gain regimens in athletes. Although some research has been conducted in the past 5years, research on intentional weight gain is lacking. Currently, available data suggests that weekly weight gain of 0.45kg (1lb), primarily as LBM, may be difficult for some athletes to achieve. Available evidence, however, suggests that commonly recommended strategies to promote calorie surplus, including consuming larger portions, incorporating energy-dense foods, and prioritizing liquid over solid foods, may prove helpful.

Estradiol replacement improves high-fat diet-induced insulin resistance in ovariectomized rats.

The role of 17β‐estradiol (E2) in high‐fat diet (HFD)‐induced alteration of the protein kinase B (Akt) signaling pathway in ovariectomized (OVX) rats is unclear. Therefore, we examined whether chronic estrogen replacement restores HFD‐induced impairment in insulin sensitivity by its effects concomitant with alterations in the Akt isoform 2 (Akt2) and Akt substrate of 160 kDa (AS160) phosphorylation in muscles of OVX rats. Nine‐week‐old female Wistar rats underwent ovariectomy under anesthesia; after 4 weeks, subcutaneous implantation of either E2 or placebo (PL) pellets was performed, and HFD feeding was initiated. Intravenous glucose tolerance tests were performed to assess insulin sensitivity. Following insulin injection into rats’ portal vein, the liver and gastrocnemius muscle were dissected for insulin signaling analysis. We observed that HFD increased energy intake and body weight in the PL group; however, it was temporarily decreased in the E2 group. Adipose tissue accumulation was larger in HFD‐fed rats than in normal chow diet (NCD)‐fed rats in the PL group; however, this difference was not observed in the E2 group. HFD reduced insulin sensitivity in the PL group only. In vivo insulin stimulation increased Akt2 phosphorylation in the muscles of NCD‐fed rats in both groups. In contrast, HFD affected insulin‐stimulated phosphorylation of Akt2 and AS160 in the muscles of rats in the PL group but not in the E2 group. Our data suggest that E2 replacement improves HFD‐induced insulin resistance, and this effect is accompanied by the alterations in the Akt2 and AS160 phosphorylation in insulin‐stimulated muscles of OVX rats.

Influence of Sensory Properties in Moderating Eating Behaviors and Food Intake.

Sensory properties inform likes and dislikes, but also play an important functional role in guiding food choice and intake behavior. Odors direct food choice and stimulate sensory-specific appetites and taste helps to anticipate calorie and nutrient content of food. Food textures moderate eating rate and the energy consumed to satiation and post-ingestive metabolism. We summarize how sensory cues moderate intake, and highlight opportunities to apply sensory approaches to improve dietary behavior. Salt, sweet and savory taste influence liking, but also influence energy intake to fullness, with higher taste intensity and duration linked to lower intake. Psycho-physical studies show it is relatively easy to rank taste intensities at different concentrations but more challenging to discriminate fat contents, and fat discrimination declines further when combined with high-taste intensity. Fat has low impact on sensory intensity, but makes significant contributions to energy content. Combinations of high taste and fat-content can promote passive energy over-consumption, and adding fat also increases energy intake rate (kcals/min), reducing opportunities to orally meter consumption. Consumers adapt their oral processing behaviors to a foods texture, which can influence the rate and extent of energy intake. Understanding how texture influences eating behaviors and bolus formation, affords new opportunities to impact eating rate, energy intake and metabolic response to food. Food formulation has traditionally focused on composition and sensory appeal. Future research needs to consider the role of sensory properties in moderating consumer interaction with their food environment, and how they influence calorie selection, and shape our eating behaviors and intake.

Ultra-processed food intake and diet carbon and water footprints: a national study in Brazil.

ABSTRACTOBJECTIVE To study the association between ultra-processed food consumption and carbon and water footprints of the Brazilian diet.METHODS Cross-sectional analysis on data collected in 2008–2009 on a probabilistic sample of the Brazilian population aged ≥ 10 years (n = 32,886). Individual food intake was assessed using two 24-hour food records, on non-consecutive days. The environmental impact of individual diets was calculated by multiplying the amount of each food by coefficients that quantify the atmospheric emissions of greenhouse gases in grams of carbon dioxide equivalent (carbon footprint) and freshwater use in liters (water footprint), both per gram or milliliter of food. The two coefficients consider the food life cycle ‘from farm to fork.’ Crude and adjusted linear regression models and tests for linear trends assessed the association between the ultra-processed food contribution to total energy intake (quintiles) and the diet carbon and water footprints. Potential confounders included age, sex, education, income, and region. Total energy intake was assessed as a potential mediation variable.RESULTS In the crude models, the dietary contribution of ultra-processed foods was linearly associated with the carbon and water footprints of the Brazilian diet. After adjustment for potential confounders, the association remained significant only regarding the diet water footprint, which increased by 10.1% between the lowest and highest quintile of the contribution of ultra-processed foods. Additional adjustment for total energy intake eliminated this association indicating that the dietary contribution of ultra-processed foods increases the diet water footprint by increasing energy intake.CONCLUSIONS The negative impact of ultra-processed foods on the diet water footprint, shown for the first time in this study, adds to the negative impacts of these foods, already demonstrated regarding dietary nutrient profiles and the risk for several chronic non-communicable diseases. This reinforces the recommendation to avoid ultra-processed foods made in the official Brazilian Dietary Guidelines and increasingly in dietary guidelines of other countries.

The nonshivering thermogenesis of brown adipose tissue and fat mobilization of striped hamsters exposed to cycles of cold and warm temperatures

The adaptive adjustments in the capacity for metabolic thermogenesis are critical for the survival in many small mammals that are acclimated to cold winter conditions. In this study the striped hamsters (Cricetulus barabensis) were subjected to repeated cycles of cold (5°C) and warm (23°C) temperatures. Resting metabolic rate (RMR), nonshivering thermogenesis (NST) and energy intake, as well as the expression of uncoupling protein 1 (UCP1) of brown adipose tissue (BAT) and serum thyroid hormone levels were measured. Both RMR and NST were significantly increased in striped hamsters subjected to repeated cycles of short-term cold (5°C, 72 h) – warm (23°C, 4 days) temperatures compared to that of the hamsters consistently kept at 23°C. In these cycled hamsters, BAT UCP1 expression was significantly upregulated, whereas serum T3 and T4 concentration did not change significantly. Moreover, gross energy intake was considerably increased during both cold exposure and warm phases, whereas fat deposition was significantly decreased in these cycled hamsters compared to those consistently kept at 23°C. This indicates that small mammals may both increase energy intake and mobilize fat depots to cope with frequent cold exposure. Thyroid hormone may be not involved in the BAT UCP1-mediated thermogenesis and fat mobilization.

Sports Dietitian practices for assessing and managing athletes at risk of low energy availability (LEA)

ObjectivesTo characterise the assessment and management practices employed by Sports Dietitians when assessing and managing athletes at risk of low energy availability (LEA). Design55 Sports Dietitians participated in an online questionnaire that captured the typical methods used to identify and manage LEA in athletic populations. MethodsThe questionnaire consisted of 27 questions which explored common methods used to identify and manage LEA, as well as dietary methods employed and barriers experienced by Sports Dietitians. ResultsBroadly, the top 3 nutrition-related priorities for respondents were nutrition strategies to support training, competition, and recovery while ‘LEA’ was ranked fifth. ‘Dietary intake’, ‘menstrual function’ and ‘training load (km/week)’ were the primary methods used to assess LEA and respondents were ‘confident’ in their ability to correctly identify athletes at risk. Among support personnel, coaches were rarely a referral source for management of LEA but did present frequent communication difficulties. Respondents indicated athletes have concerns about undesirable changes in body composition when providing recommendations of increased energy intake for LEA management. ConclusionsSport Dietitians appear to recognise and prioritise LEA management in athletes, but assessments are limited to dietary intake and training load (km/week); with collaborative approaches to LEA management lacking. Sports Dietitian may be overconfident in their ability to identify LEA as only a limited number of assessment methods are commonly used. Access to reliable assessments methods and collaborative management approaches are needed to improve athlete care when suspected of LEA.

Nutrition research challenges for processed food and health.

Existing highly processed food (HPF) classification systems show large differences in the impact of these foods on biochemical risk factors for disease. If public health nutrition is to consider the degree of food processing as an important element of the link between food and health, certain gaps in research must be acknowledged. Quantifying the food additive exposure derived from HPFs is a task made challenging by the lack of data available on the occurrence and concentration of additives in food and the degree to which the natural occurrence of additives in unprocessed foods confounds exposure estimates. The proposed role of HPFs in health outcomes could also be associated with altered nutrient profiles. Differences exist within and between HPF classification systems in this regard and there are conflicting data on the impact of controlling for nutrient intake. Furthermore, research is needed on how the sensory aspects of HPFs contribute to energy intake. Current data suggest that high energy intake rate may be the mechanism linking HPFs and increased energy intake. A high priority now is to clarify the basis of definitions used to categorize foods as highly processed and, in a constructive sense, to distinguish between the contributions of nutrients, additives and sensory properties to health.

The Regulatory Role of the Central and Peripheral Serotonin Network on Feeding Signals in Metabolic Diseases.

Central and peripheral serotonin (5-hydroxytryptamine, 5-HT) regulate feeding signals for energy metabolism. Disruption of central 5-HT signaling via 5-HT2C receptors (5-HT2CRs) induces leptin-independent hyperphagia in mice, leading to late-onset obesity, insulin resistance, and impaired glucose tolerance. 5-HT2CR mutant mice are more responsive than wild-type mice to a high-fat diet, exhibiting earlier-onset obesity and type 2 diabetes. High-fat and high-carbohydrate diets increase plasma 5-HT and fibroblast growth factor-21 (FGF21) levels. Plasma 5-HT and FGF21 levels are increased in rodents and humans with obesity, type 2 diabetes, and non-alcohol fatty liver diseases (NAFLD). The increases in plasma FGF21 and hepatic FGF21 expression precede hyperinsulinemia, insulin resistance, hyperglycemia, and weight gain in mice fed a high-fat diet. Nutritional, pharmacologic, or genetic inhibition of peripheral 5-HT synthesis via tryptophan hydroxylase 1 (Tph1) decreases hepatic FGF21 expression and plasma FGF21 levels in mice. Thus, perturbing central 5-HT signaling via 5-HT2CRs alters feeding behavior. Increased energy intake via a high-fat diet and/or high-carbohydrate diet can upregulate gut-derived 5-HT synthesis via Tph1. Peripheral 5-HT upregulates hepatic FGF21 expression and plasma FGF21 levels, leading to metabolic diseases such as obesity, insulin resistance, type 2 diabetes, and NAFLD. The 5-HT network in the brain–gut–liver axis regulates feeding signals and may be involved in the development and/or prevention of metabolic diseases.