Effect of the fatty acid composition of meals on postprandial energy expenditure: a systematic review

SUMMARY The energy imbalance produced by an increase in caloric intake and/or decrease in energy expenditure induces obesity. However, the fatty acid composition of a diet can affect the metabolism in different ways, having a role in the development of obesity. AIM To determine the effect of different fatty acids types and composition on Diet-Induced Thermogenesis (DIT) and postprandial energy expenditure in humans. METHODS A search in the PubMed and Web of Science databases, yielded a total of 269 potential articles as a first result; 254 were excluded according to the criteria. RESULTS Fifteen articles were used for this systematic review. The studies analyzed report different effects of the fatty acids of the treatment on the diet-induced thermogenesis. Evidence indicates that the consumption of polyunsaturated fatty acids causes a greater DIT than saturated fatty acids. Also, the consumption of medium-chain fatty acids compared to long-chain fatty acids has been shown to increase DIT. Likewise, the use of certain oils has shown positive effects on postprandial energy expenditure, as is the case of olive oil, compared to rapeseed oil. CONCLUSIONS The use of specific types of fatty acids in the everyday diet can increase postprandial energy expenditure in humans. Nevertheless, longer-term studies are required.

RESUMO O desequilíbrio energético produzido pelo aumento da ingestão calórica e/ou diminuição do gasto energético provoca obesidade. Sem embargo, a composição de ácidos graxos da dieta pode afetar diferencialmente o metabolismo, tendo um papel no desenvolvimento da obesidade. OBJETIVO Determinar os efeitos de diferentes tipos de ácidos graxos e sua composição na termogênese induzida por dieta e no gasto energético pós-prandial em humanos. MÉTODOS Uma busca nas bases de dados da PubMed e da Web of Science gerou um total de 269 artigos potenciais como primeiro resultado; 254 foram excluídos de acordo com os critérios. RESULTADOS Quinze artigos foram utilizados para esta revisão sistemática. Os estudos analisados informam os efeitos diferenciais dos ácidos graxos no tratamento da termogênese induzida pela dieta. As evidências indicam que o consumo dos ácidos graxos poli-insaturados ocasiona maior DIT que os ácidos graxos saturados. Além disso, demonstra-se que o consumo dos ácidos graxos da cadeia média, em comparação com os ácidos graxos da cadeia longa, aumenta o DIT. Do mesmo modo, o uso de certos azeites demonstra os efeitos positivos sobre o gasto de energia pós-prandial, como é o caso do azeite de oliva, em comparação com o azeite de colza. CONCLUSÃO O uso de tipos específicos de ácidos graxos na dieta habitual pode aumentar o gasto de energia pós-prandial nos seres humanos. Sem embargo, é necessária maior investigação no longo prazo.

Neonatal tobacco smoke reduces thermogenesis capacity in brown adipose tissue in adult rats

Maternal smoking is a risk factor for progeny obesity. We have previously shown, in a rat model of neonatal tobacco smoke exposure, a mild increase in food intake and a considerable increase in visceral adiposity in the adult offspring. Males also had secondary hyperthyroidism, while females had only higher T4. Since brown adipose tissue (BAT) hypofunction is related to obesity, here we tested the hypothesis that higher levels of thyroid hormones are not functional in BAT, suggesting a lower metabolic rate. We evaluated autonomic nerve activity in BAT and its function in adult rats that were exposed to tobacco smoke during lactation. At birth, litters were adjusted to 3 male and 3 female pups/litter. From postnatal day (PND) 3 to 21, Wistar lactating rats and their pups were divided into SE group, smoke-exposed in a cigarette smoking machine (4 times/day) and C group, exposed to filtered air. Offspring were sacrificed at PND180. Adult SE rats of both genders had lower interscapular BAT autonomic nervous system activity, with higher BAT mass but no change in morphology. BAT UCP1 and CPT1a protein levels were decreased in the SE groups of both genders. Male SE rats had lower β3-AR, TRα1, and TRβ1 expression while females showed lower PGC1α expression. BAT Dio2 mRNA and hypothalamic POMC and MC4R levels were similar between groups. Hypothalamic pAMPK level was higher in SE males and lower in SE females. Thus, neonatal cigarette smoke exposure induces lower BAT thermogenic capacity, which can be obesogenic at adulthood.

Regulation of adiposity by mTORC1 / Controle da adiposidade por mTORC1

ABSTRACT Obesity is characterized by an excessive increase in the adipose tissue mass, and is associated with higher incidence of several chronic metabolic diseases, such as type 2 diabetes. Therefore, its increasing prevalence is a public health concern, and it is important to better understand its etiology to develop new therapeutic strategies. Evidence accumulated over the years indicates that obesity is associated with a marked activation in adipose tissue of the mechanistic target of rapamycin complex 1 (mTORC1), a signaling pathway that controls lipid metabolism, and adipocyte formation and maintenance. Curiously, mTORC1 is also involved in the control of nonshivering thermogenesis and recruitment as well as browning of white adipose tissue. In this review, we explored mTORC1 functions in adipocytes and presented evidence, suggesting that mTORC1 may either increase or reduce adiposity, depending on the conditions and activation levels.

RESUMO A obesidade é caracterizada pelo aumento excessivo da massa de tecido adiposo, estando associada à maior incidência de diversas doenças metabólicas crônicas, como diabetes tipo 2. Sua crescente prevalência é uma questão de saúde pública, e faz-se importante compreender melhor sua etiologia, para desenvolver novas estratégias terapêuticas. As evidências acumuladas por muitos anos indicam que a obesidade está associada à significativa ativação no tecido adiposo do complexo 1 da proteína alvo mecanístico da rapamicina (mTORC1), uma via de sinalização que regula o metabolismo de lipídeos, bem como a formação e manutenção de adipócitos. Curiosamente, mTORC1 também está envolvido no controle da termogênese, independente do tremor muscular, e no recrutamento e browning de tecido adiposo branco. Nesta revisão, exploramos as diferentes funções do mTORC1 em adipócitos e apresentamos evidências que sugerem que o mTORC1 pode aumentar ou reduzir a adiposidade, dependendo das condições e de seu nível de ativação.

Water temperature, body mass and fasting heat production of pacu (Piaractus mesopotamicus)

ABSTRACT Knowledge on fasting heat production (HEf) of fish is key to develop bioenergetics models thus improving feeding management of farmed species. The core of knowledge on HEf of farmed, neotropical fish is scarce. This study assessed the effect of body mass and water temperature on standard metabolism and fasting heat production of pacu, Piaractus mesopotamicus, an omnivore, Neotropical fresh water characin important for farming and fisheries industries all through South American continent. An automated, intermittent flow respirometry system was used to measure standard metabolic rate (SMR) of pacu (17 - 1,050 g) at five water temperatures: 19, 23, 26, 29 and 33 °C. Mass specific SMR increased with increasing water temperature but decreased as function of body mass. The allometric exponent for scaling HEf was 0.788, and lied in the range recorded for all studied warm-water fish. The recorded van't Hoff factor (Q10) for pacu (2.06) shows the species low response to temperature increases. The model HEf = 0.04643×W0.7882×T1.837 allows to predict HEf (kJ d-1) from body mass (W, kg) and water temperature (T, °C), and can be used in bioenergetical models for the species.

The consensus sequence of FAMLF alternative splice variants is overexpressed in undifferentiated hematopoietic cells

The familial acute myeloid leukemia related factor gene (FAMLF) was previously identified from a familial AML subtractive cDNA library and shown to undergo alternative splicing. This study used real-time quantitative PCR to investigate the expression of the FAMLF alternative-splicing transcript consensus sequence (FAMLF-CS) in peripheral blood mononuclear cells (PBMCs) from 119 patients with de novo acute leukemia (AL) and 104 healthy controls, as well as in CD34+ cells from 12 AL patients and 10 healthy donors. A 429-bp fragment from a novel splicing variant of FAMLF was obtained, and a 363-bp consensus sequence was targeted to quantify total FAMLF expression. Kruskal-Wallis, Nemenyi, Spearman's correlation, and Mann-Whitney U-tests were used to analyze the data. FAMLF-CS expression in PBMCs from AL patients and CD34+ cells from AL patients and controls was significantly higher than in control PBMCs (P<0.0001). Moreover, FAMLF-CS expression in PBMCs from the AML group was positively correlated with red blood cell count (rs =0.317, P=0.006), hemoglobin levels (rs =0.210, P=0.049), and percentage of peripheral blood blasts (rs =0.256, P=0.027), but inversely correlated with hemoglobin levels in the control group (rs =–0.391, P<0.0001). AML patients with high CD34+ expression showed significantly higher FAMLF-CS expression than those with low CD34+ expression (P=0.041). Our results showed that FAMLF is highly expressed in both normal and malignant immature hematopoietic cells, but that expression is lower in normal mature PBMCs.

Brown adipose tissue: what have we learned since its recent identification in human adults / Tecido adiposo marrom: o que aprendemos desde sua recente identificação em humanos adultos

Brown adipose tissue, an essential organ for thermoregulation in small and hibernating mammals due to its mitochondrial uncoupling capacity, was until recently considered to be present in humans only in newborns. The identification of brown adipose tissue in adult humans since the development and use of positron emission tomography marked with 18-fluorodeoxyglucose (PET-FDG) has raised a series of doubts and questions about its real importance in our metabolism. In this review, we will discuss what we have learnt since its identification in humans as well as both new and old concepts, some of which have been marginalized for decades, such as diet-induced thermogenesis. Arq Bras Endocrinol Metab. 2014;58(9):889-99.

O tecido adiposo marrom, órgão essencial para a termorregulação de animais hibernantes e pequenos devido à sua capacidade desacopladora, era até poucos anos considerado presente apenas em recém-nascidos na espécie humana. A identificação do tecido adiposo marrom em adultos com o desenvolvimento e uso da tomografia de emissão de pósitron marcado com 18-fluorodesoxiglicose (PET-FDG) gerou questões sobre sua real importância para nosso metabolismo. Nesta revisão, discutiremos o que aprendemos nesse tempo, assim como conceitos antigos e novos, alguns marginalizados por décadas, como a termogênese induzida por dieta. Arq Bras Endocrinol Metab. 2014;58(9):889-99.

Postprandial thermogenesis in Bothrops moojeni (Serpentes: Viperidae)

Snakes that can ingest prey that are proportionally large have high metabolic rates during digestion. This great increase in metabolic rate (specific dynamic action - SDA) may create a significant augment in the animal's body temperature. The present study investigated postprandial thermogenesis in Bothrops moojeni. Briefly, two groups of snakes were fed meals equivalent to 17 ± 3 percent and 32 ± 5 percent of their body weight and were observed for 72 hours, in which thermal images of each snake were taken with an infrared camera in a thermostable environment with a constant air temperature of 30ºC. The results showed a significant increase in snake surface temperature, with a thermal peak between 33 and 36 hours after feeding. The meal size had a great impact on the intensity and duration of the thermogenic response. Such increase in temperature appears to be connected with the huge increase in metabolic rates during digestion of relatively large prey by snakes that feed infrequently. The ecologic implication of the thermogenic response is still not well understood; however, it is possible that its presence could affect behaviors associated with the snake digestion, such as postprandial thermophily.

The brain is the conductor: diet-induced inflammation overlapping physiological control of body mass and metabolism: [review] / O cérebro é o maestro: inflamação induzida por dieta interfere no controle fisiológico da adiposidade corporal e do metabolismo: [revisão]

Obesity is currently a worldwide pandemic. It affects more than 300 million humans and it will probably increase over the next 20 years. The consumption of calorie-rich foods is responsible for most of the obesity cases, but not all humans exposed to high-calorie diets develop the disease. This fact has prompted researchers to investigate the mechanisms linking the consumption of high-calorie diets to the generation of an imbalance between energy intake and expenditure. According to recent studies, the exposure to fat-rich diets induces an inflammatory response in the hypothalamic areas involved in the control of feeding and thermogenesis. The inflammatory process damages the neuronal circuitries that maintain the homeostatic control of the body's energy stores, therefore favoring body mass gain. This review will focus on the main advances obtained in this field.

Obesidade é hoje um grave problema de saúde pública no mundo. Mais de 300 milhões de pessoas são obesas e esse número deve crescer substancialmente nos próximos 20 anos. As dietas ricas em calorias são a principal causa de obesidade, porém, nem todos os indivíduos expostos a dietas altamente calóricas se tornam obesos. Tal fato estimulou pesquisadores a investigarem os mecanismos que ligam o consumo de dietas ricas em calorias ao desenvolvimento de um balanço inadequado entre consumo e gasto energético. De acordo com estudos recentes, o consumo de dietas ricas em gorduras induz a ativação de uma resposta inflamatória nas áreas do hipotálamo envolvidas com o controle da fome e da termogênese. Tal processo inflamatório lesa os circuitos neuronais que mantêm o controle homeostático das reservas corporais de energia, favorecendo assim o ganho de massa adiposa. Esta revisão irá focar os principais avanços obtidos nesta área.

Contribuição renal para a termoregulação: termogênese e a doença renal / Renal contribution to thermoregulation: thermogenesis and renal disease

O presente estudo apresenta inicialmente uma breve revisão da fisiologia da termogênese e suas relações com atividade renal. Embora se saiba que o rim tem uma intensa atividade metabólica, o impacto de sua contribuição à manutenção da homeostase térmica não foi ainda devidamente avaliado. Através de um modelo concebido para promover o isolamento térmico em animais ratos Sprague-Dawley; aferimos, após 30 minutos, um ganho térmico de 2.77 ± 0.47°C no grupo com nefrectomia 5/6; 2.56 ± 0.24°C no grupo denervado; 2.2 ± 0.42°C no grupo simulado e 2.17 ± 0.02°C em animais controles íntegros (P<0.05). Foi também coletada e aferida a massa do peso da gordura marrom com os seguintes resultados: Nx5/6: 174.5 ± 5.80(g); Dx: 233.1 ± 25.42(g) e sham: 279.6 ± 28.22(g) (P<0.005).Sugerimos que os maiores ganhos térmicos observados nos modelos parcialmente nefrectomizados (denervados e nefrectomizados) foram ocasionados por uma suposta necessidade de compensar a perda da atividade termogênica renal. Esta atividade compensatória deveu-se, sobretudo, a um aumento na queima de gordura marrom e da atividade da termogênese facultativa neste tecido.

The present study starts with a brief view of thermogenesis and its interconnections with renal activity. It is well known that the kidney has an intense metabolic activity but its true contribution to the internal temperature has not yet been well evaluated. Utilizing a system which promoted a thermal isolation in Sprague-Dawley rats, we were able to record the increase of temperature from basal internal temperatures during thirty minutes of experiment, which was associated with enhanced uncoupling protein (UCP) expression. The group of sub total nephrectomy (Nx5/6) registered a gain of 2.77 ± 0.47 °C, the denervation group (DNx): 2.56 ± 0.24°C, the sham: 2.2 ± 0.43°C, and the normal group a gain of 2.17± 0.02°C (P<0.05). We also measured the weight of brown adipose tissue (BAT) - a specialized thermogenic tissue - with the following results: Nx5/6: 174.5 ± 5.80 g; DNx: 233.1 ± 25.42 g and sham: 279.6 ± 28.22 g (P<0,005). We concluded that the higher values of thermal gain observed in these chronic injuries (denervation and nephrectomy) revealed the necessity of increase in facultative thermogenic activity to supply the loss of body heat through BATactivation.

Análise da taxa metabólica de repouso avaliada por calorimetria indireta em mulheres obesas com baixa e alta ingestão calórica / Analysis of resting metabolic rate evaluated by indirect calorimetry in obese women with low and high caloric intake

Este trabalho analisou se mulheres obesas com baixa ingestão calórica (IC), aferidas por questionário alimentar, apresentam valores diminuídos de taxa metabólica de repouso (TMR), o que favoreceria um desequilíbrio no balanço energético (BE) e conseqüente ganho de peso. Foram avaliados o índice de atividade física (AF) e sua relação com a IC em 77 mulheres obesas, com índice de massa corporal (IMC) acima de 30 kg/m², entre 20 e 45 anos. A partir dos valores da IC, as mulheres foram divididas em três grupos: baixa (G1), média (G2) e alta (G3) IC e submetidas a exame de calorimetria indireta de repouso. Foram avaliados: peso, altura, superfície de área corpórea (SAC), composição corporal por bioimpedância. O G1 apresentou maior valor de peso, SAC, peso de gordura corpórea e também valores abaixo de 1,2 na razão IC:TMR, o que indica provável subestimação da IC. Os maiores valores de AF e de TMR (por quilo de massa magra) foram verificados no G3. O G1 apresentou o BE mais negativo. O G3 apresentou valores positivos. Em suma, este estudo mostrou que existe tendência à subestimação da IC de algumas mulheres obesas e que a manutenção do peso corporal em algumas pacientes se deve ao baixo nível de AF.

The aim of this study was to evaluate if obese women with the lowest values of caloric intake (CI) determined by food questionnaire also present the lowest values of resting metabolic rate (RMR), which could lead to excessive weight gain, caused by changes in energy balance. With this porpouse, 77 obese women, with IMC > 30kg/m², aged 20 to 45 years, had their physical activity level and CI evaluated. According to the values of CI obtained from food intake reports, the participants were divided in 3 groups: low (G1), medium (G2), high (G3) CI and were submitted to indirect calorimetry. Height, weight, body surface area (BSA), fat free mass and fat mass measured by bioimpedance were evaluated. The highest values of weight, BSA an fat mass were obtained in G1, as well as values above 1.2 for the CI:RMR ratio, which indicates a probable underestimation of CI. The highest values of physical activity and RMR were observed in the G3 (with high caloric intake). In conclusion, this paper shows that a tendency towards underestimation of self-reported caloric intake exists among obese women and that the maintenance of weight in some patients can be due to their low level of physical activity.

O perfil de macronutrientes influencia a termogênese induzida pela dieta e a ingestão calórica / Macronutrient profile affects diet-induced thermogenesis and energy intake

The diet composition can interfere directly in the energy homeostase. In the energy metabolism, the oxidation pathway and diet-induced thermogenesis are differentiated by diet macronutrients proportion. In this respect, the high-proteindiet is the most thermogenic, compared to high-carbohydrate and high-lipid diets, while high-carbohydrate diet appears to increase the thermogenic effect more than high-lipid diet, but the studies arecontroversies. Towards energy intake, it can stimulate or inhibit the energy intake, according to the foods palatability, satiation and satiety degree, related to diet carbohydrate, protein and lipid content. A hierarchy has been observed for the satiating efficacies of the macronutrients protein, carbohydrate and fat, with protein as most satiating and fat as least satiating. In general, there are discrepancies between studies about the regulatory role of macronutrients in the components of energy expenditure and intake, due the methodological differences in the subjects, exposition time for diet, energy density, and total energy content. The present work seeks to analyze the more consistent scientific evidences toward the modulator role of diet composition on the diet induced thermogenesis and energy intake, for better understanding of obesity prevention and control by dietetic intervention.

A composição da dieta pode interferir diretamente na homeostase energética. No metabolismo energético, a via de oxidação e a termogênese induzida pela dieta são diferenciadas pela proporção de macronutrientes da dieta. Neste sentido, a dieta hiperprotéica émais termogênica que as dietas hiperglicídicas e hiperlipídicas, enquanto que as dietas ricas em carboidrato parecem ser mais termogênicas que as ricas em lipídio, mas os resultados ainda são controversos. Em relação à ingestão calórica, a composição da dieta pode estimular ou inibir a mesma, de acordo com a palatabilidade dos alimentos e o grau de saciação e saciedade, relacionadas às quantidades de carboidrato, proteína e lipídio da mesma. Uma hierarquia tem sido relatada para a capacidade dos macronutrientes em induzir saciedade em que a proteína é o mais sacietógeno ao contrário dos lipidios, que são os menos sacietógenos. De modo geral, ainda há discrepâncias entre os estudos, em relação ao papel regulador dos macronutrientes em componentes do gasto energético e na ingestão calórica, devido às diferenças metodológicas como amostra, tempo de exposição à dieta, densidade calórica e conteúdo calórico total da mesma. Desta forma, o presente trabalho tem como objetivo analisar as evidências científicas mais consistentes a respeito do papel modulador da composição da dieta na termogênese induzida pela dieta e na ingestão calórica, para melhor entendimento da prevenção e controle da obesidade pela intervenção dietética.

O controle hipotalâmico da fome e da termogênese: implicações no desenvolvimento da obesidade / The hypothalamic control of feeding and thermogenesis: implications on the development of obesity

O aumento da prevalência de obesidade em várias regiões do planeta vem se revelando como um dos mais importantes fenômenos clínico-epidemiológicos da atualidade. Fatores como a mudança do hábito alimentar e o estilo de vida sedentário, aliados a determinantes genéticos ainda pouco conhecidos, desempenham um papel relevante na patogênese desta doença. Nos últimos dez anos, desde o descobrimento do hormônio leptina, avanços consideráveis foram obtidos na caracterização dos mecanismos hipotalâmicos do controle da ingestão alimentar e da termogênese. Tais avanços têm revelado as particularidades de um sistema complexo e integrado, e têm oferecido novas perspectivas para abordagens terapêuticas farmacológicas específicas. Esta revisão apresenta os mais recentes avanços nesta área, tendo como foco a ação hipotalâmica da leptina e da insulina e explorando a hipótese de que a resistência à ação central destes hormônios possa ser o elo entre a obesidade e as outras condições clínicas nas quais a resistência à insulina desempenha um papel patogenético proeminente.

The worldwide increase in the prevalence of obesity is becoming one of the most important clinical-epidemiological phenomena of the present days. Environmental factors such as changes in life-style and feeding behavior associated with poorly characterized genetic determinants are though to play the most important roles in the pathogenesis of this disease. During the last ten years, since the discovery of leptin, great advances were obtained in the characterization of the hypothalamic mechanisms involved in the control of food intake and thermogenesis. Such advances are unveiling a complex and integrated system and are opening a wide perspective for the finding of novel therapeutic targets for the treatment of this harming condition. This review will present some of the most recent findings in this field. It will be focused on the actions of leptin and insulin in the hypothalamus and will explore the hypothesis that hypothalamic resistance to the action of these hormones may play a role in the development of obesity and may act as a molecular link between obesity, type 2 diabetes mellitus and other clinical conditions on which insulin resistance plays an important pathogenetic role.