El ayuno intermitente y sus efectos en la salud metabólica en humanos / Intermittent fasting and human metabolic health

Intermittent fasting (IF) has gained increasing scientific and general attention. Most studied forms of IF include alternate-day fasting, modified alternate-day fasting, and time-restricted eating (TRE). Several cardiometabolic effects of IF have been described in animal models and, to a lesser extent, in humans. This review analyzes the impact of IF on weight loss, glucose metabolism, blood pressure, and lipid profile in humans. A literature search was conducted in the Pubmed/Medline, Scopus, and Google Scholar databases. Controlled observational or interventional studies in humans, published between January 2000 and June 2021, were included. Studies comparing IF versus religious fasting were not included. Most studies indicate that the different types of IF have significant benefits on body composition, inducing weight loss and reducing fat mass. Changes in cardiometabolic parameters show more divergent results. In general, a decrease in fasting glucose and insulin levels is observed, together with an improved lipid profile associated with cardiovascular risk. High heterogeneity in study designs was observed, particularly in studies with TRE, small sample sizes, and short-term interventions. Current evidence shows that IF confers a range of cardiometabolic benefits in humans. Weight loss, improvement of glucose homeostasis and lipid profile, are observed in the three types of IF protocols evaluated.

Sodium butyrate in post-hatch feed for broiler chicks / [Uso de butirato de sódio em rações pós-eclosão para pintos de corte]

This study was designed to determine adequate levels for sodium butyrate inclusion in pre-hatching and pre-starter feed in order to minimize the negative effects of post-hatch delayed placement on broiler chicks. Newly-hatched chicks were allotted in a completely randomized design, with five treatments, each comprising five replicates of ten birds each. Five dietetic levels of sodium butyrate (control, 0.050, 0.075, 0.100 and 0.200%) were used in the pre-starter feed offered to the chicks in the transporting box and during the pre-starter phase. Performance, yolk sac retraction, plasma glucose concentration, weight and histomorphometry of the small intestine were evaluated after 24 hours of feed access and at 7 days of age. A metabolic trial was performed when the chicks were seven to ten days of age. Supplementation of 0.1% sodium butyrate increased the development of broiler chicks' intestinal villi at seven days of age but was not able to improve performance in the pre-starter phase. Supplementation with sodium butyrate in a diet offered in the transportation box does not improve broiler performance in the pre-starter phase. Supplementation of up to 0.16% is recommended, in order to improve the metabolizability of the ether extract for broilers at seven days of age.(AU)

Objetivou-se, com este estudo, encontrar níveis adequados de inclusão de butirato de sódio em ração pós-eclosão e pré-inicial, buscando minimizar os efeitos negativos do jejum de pintos de corte. Os animais foram distribuídos em delineamento inteiramente ao acaso, com cinco tratamentos e cinco repetições de 10 aves cada. Foram utilizadas cinco suplementações de butirato de sódio (controle; 0,05; 0,075; 0,100 e 0,200%) na ração pré-inicial, fornecidas aos pintos na caixa de transporte e durante a fase pré-inicial. Após 24 horas de acesso ao alimento e aos sete dias de idade, foram avaliados desempenho, retração do saco vitelino, concentração de glicose plasmática, peso e histomorfometria do intestino delgado. De sete a 10 dias de idade, realizou-se ensaio de metabolizabilidade. A suplementação de 0,10% de butirato de sódio aumentou o desenvolvimento das vilosidades intestinais dos pintos de corte aos sete dias de idade, mas não foi capaz de melhorar o desempenho na fase pré-inicial. A suplementação com butirato de sódio em dieta oferecida na caixa de transporte não melhora o desempenho dos frangos na fase pré-inicial. Recomenda-se suplementação de até 0,16%, a fim de melhorar a metabolizabilidade do extrato etéreo para frangos de corte aos sete dias de idade.(AU)

Duración del ayuno preoperatorio en pacientes con cirugía programada / Duration of preoperative fasting in patients with scheduled surgery

Antecedentes y objetivo: el ayuno preoperatorio disminuye el riesgo de aspiración del contenido gástrico y sus complicaciones. Sin embargo, si es excesivo, favorece la regurgitación y el riesgo de broncoaspiración tras la inducción anestésica, así como alteraciones metabólicas e hidroelectrolíticas. Analizamos su duración, en pacientes con cirugías programadas en un hospital público de agudos. Material y métodos: se encuestó a todos los pacientes mayores de 18 años con cirugías programadas. Se recolectaron datos sobre la prescripción médica de ayuno, la hora de inducción anestésica y personales. El ayuno prescripto se comparó con las recomendaciones de las guías de la AAARBA (Asociación de Anestesia, Analgesia y Reanimación de Buenos Aires). Resultados: se reclutaron 139 pacientes, con una mediana de edad de 48 años (30; 64), 53% femeninos. La mediana del ayuno prescripto fue de 12,5 horas tanto para sólidos como para líquidos. El ayuno para sólidos que realizaron los pacientes tuvo una mediana de 14 horas, la cual resultó significativamente mayor que la prescripción (p < 0,001). En cambio, el ayuno para líquidos tuvo una mediana de 12 horas, no hallándose una diferencia significativa (p = 0,452) con lo prescripto. En comparación con la guía de la AAARBA, el ayuno prescripto excedió la recomendación para sólidos (4,5 h) y para líquidos (10,5 h). El ayuno realizado por el paciente excedió lo prescripto para sólidos (1,5 h), mientras que para líquidos fue inferior (0,5 h). Conclusión: el ayuno preoperatorio prescripto no se adecuó a las recomendaciones actuales. Las horas de ayuno realizadas por el paciente resultaron excesivas. (AU)

Background and objective: preoperative fasting reduces the risk of aspiration of gastric contents and its complications. However, if fasting is excessive, it favours regurgitation and the risk of pulmonary aspiration in patients undergoing general anaesthetic, such as metabolic and electrolyte disorders. We analysed its duration in patients with elective surgeries in public acute care hospital. Material and methodologies: patients over 18 years old with elective surgeries were surveyed. Data about medical fasting indication, time of induction of anaesthesia and personal information was collected. The prescribed fast was compared with the recommendations of the AAARBA (Association of Anaesthesia, Analgesia and Reanimation of Buenos Aires) guidelines. Results: 139 patients were gathered with a median of 48 years old (30; 64), 53% of them were female. Fasting indication median was of 12.5 h for solids and liquids. The fasting made by the patient for solids had a median of 14 h which resulted to be significantly higher to the indication (p < 0.001). By contrast, the fasting for liquids had a median of 12 h which it did not show a significant difference (p = 0.452) with the indication. In comparison with the AAARBA guideline, the fasting indication exceeded the recommendation for solids (4.5 h) and for liquids (10.5 h). The fasting made by the patient exceeded to what was indicated for solids (1.5 h) while for liquids, it was inferior (0.5 h). Conclusion: the indicated preoperative fasting was not adequate to the current recommendations. The hours of fasting made by patient were excessive. (AU)

Low energy reserves are associated with fasting susceptibility in Neotropical nectar bats Glossophaga soricina / Baixas reservas energéticas corporais estão associadas à susceptibilidade ao jejum da espécie Glossophaga soricina

Abstract Neotropical nectar-feeding bats consume large amounts of sugar and use most of their energy-rich diet directly from the bloodstream, suggesting an adaptation towards lower body energy reserves. Here we tested the hypothesis that bats Glossophaga soricina spare the energy costs of storing energy reserves, even if this would represent a risky susceptibility during fasting. Blood glucose concentrations in 18 h fasted bats showed a 40% decrease. Breast muscle and adipose tissue lipids, as well as carcass fatty acids and liver glycogen, were also decreased following fasting. The inability to keep normoglycemia following a short-term fasting (i.e. 28 h) confirm that nectar bats invest little on storing energy reserves and show a severe fasting susceptibility associated to this pattern. Our study also support the general hypothesis that evolutionary specializations towards nectar diets involve adaptations to allow a decreased body mass, which reduces the energy costs of flight while increases foraging time.

Resumo Morcegos nectarívoros que ocorrem na região Neotropical consomem grandes quantidades de carboidratos, e usam a energia obtida da dieta diretamente, a partir da glicose na circulação sanguínea. Esta adaptação sugere que morcegos nectarívoros tenham evoluído no sentido de apresentar adaptações fisiológicas que permitam o baixo armazenamento de reservas energéticas corporais. Nós testamos a hipótese de que morcegos Glossophaga soricina poupam o gasto energético envolvido com a formação de reservas energéticas teciduais, mesmo que isso represente uma arriscada suscetibilidade da espécie frente ao jejum. As concentrações de glicose apresentaram uma diminuição de 40% após 18 h de jejum. As concentrações de lipídios do músculo peitoral e do tecido adiposo, bem como as de ácidos graxos da carcaça e glicogênio hepático também diminuíram após 18 h de jejum. A incapacidade de manter a normoglicemia observada após o jejum de curto-prazo confirma que morcegos nectarívoros desta espécie não investem na formação de reservas energéticas, e apresentam, consequentemente, uma severa susceptibilidade ao jejum. Este estudo suporta a hipótese de que adaptações evolucionárias da espécie envolvem diminuição da massa corporal, reduzindo o custo energético do voo e aumentado o tempo de forrageamento.

Efeitos da abreviação do jejum pré-operatório com solução de carboidrato e proteína em sintomas pós-operatórios de cirurgias ginecológicas: ensaio clínico randomizado controlado duplo-cego / Effects of preoperative fasting abbreviation with carbohydrate and protein solution on postoperative symptoms of gynecological surgeries: double-blind randomized controlled clinical trial

RESUMO Objetivo: investigar os efeitos da abreviação do jejum pré-operatório, uma recomendação do protocolo de "Aceleração da Recuperação Total Pós-operatória" (ACERTO), em sintomas pós-operatórios de pacientes submetidas à cirurgias ginecológicas. Métodos: estudo controlado, randomizado, duplo-cego, de 80 cirurgias ginecológicas realizadas no período de janeiro a junho de 2016. As pacientes foram aleatoriamente alocadas em dois grupos: Grupo Controle, com 42 pacientes, e Grupo Suco, com 38, e que receberam, respectivamente, 200ml de solução inerte ou 200ml de líquido enriquecido com carboidrato e proteína quatro horas antes da cirurgia. Os sintomas pós-operatórios estudados foram sede, fome, dor, agitação, satisfação e bem-estar, em ambos os grupos. Para medir a intensidade dos sintomas foi utilizada a Escala Visual Analógica (EVA), associada à Escala Facial (EF) para dor, aplicadas dez horas após a cirurgia. Resultados: as pacientes do Grupo Suco apresentaram menos dor (3,51x1,59), sede (3,63x0,85), fome (3,86x2,09) e agitação (2,54x0,82) em relação ao Grupo Controle (P<0,05). As variáveis satisfação (6,89x8,68) e bem-estar (5,51x7,12) foram maiores (P<0,05) quando houve a ingestão do líquido contendo carboidrato e proteína (Grupo Suco) em relação à solução inerte (Grupo Controle). Conclusão: a abreviação do jejum pré-operatório com líquido contendo carboidrato e proteína antes de cirurgias ginecológicas reduz sede, fome, dor, agitação e favorece maior satisfação e bem-estar do que a ingestão de solução inerte.

ABSTRACT Objective: to investigate the effects of preoperative fasting abbreviation, a recommendation of Postoperative Accelerated Total Recovery protocol (ACERTO protocol), on postoperative symptoms of patients undergoing gynecological surgeries. Methods: a double-blind randomized controlled study of 80 gynecological surgeries performed from January to June 2016. The patients were randomly allocated into two groups: Controle Group, with 42 patients, and Juice Group, with 38 patients, who received 200ml inert solution or 200ml carbohydrate- and protein-enriched liquid, respectively, four hours before surgery. The postoperative symptoms studied were thirst, hunger, pain, agitation, satisfaction, and well-being in both groups. To measure the intensity of symptoms, we used the Visual Analog Scale (VAS), associated with the Facial Scale (FS) for pain, applied ten hours after surgery. Results: patients in the Juice Group had less pain (3.51x1.59), thirst (3.63x0.85), hunger (3.86x2.09), and agitation (2.54x0,82) in relation to the Controle Group (P<0.05). Satisfaction (6.89x8.68) and well-being (5.51x7.12) variables were higher (P<0.05) when the carbohydrate- and protein-containing liquid (Juice Group) was ingested in relation to the inert solution (Controle Group). Conclusion: the abbreviation of preoperative fasting with carbohydrate- and protein-containing liquid before gynecological surgeries reduces thirst, hunger, pain, agitation, and favors greater satisfaction and well-being than inert solution ingestion.

Unexpectedly prolonged fasting and its consequences on elderly patients undergoing spinal anesthetics. A prospective observational study

Abstract Purpose: To measure the preoperative fasting durations with respect to time of the day and its effect on vital parameters and electrocardiogram in elderly patients undergoing surgery under spinal anesthesia. Methods: This study investigated 211 patients older than 60 years undergoing elective surgery under spinal anesthesia. Patients scheduled for surgery in morning hours (AM) and afternoon hours (PM) were compared. Patients fasting hours and repeated measurements of mean arterial pressure (MAP), heart rate (HR), peripheral oxygen saturation (Sp02) and the type and number of ischemic electrocardiogram (ECG) signs were recorded and compared [preoperative, zeroth, 2nd,5th,15th,30th minutes following spinal anesthesia(SA)]. Results: Mean fasting durations were 12±2.8 and 9.5±2.1 hours in AM group and 15.5±3.4 12.7±4.4 hours in PM group for foods and liquids respectively. ECG changes were significantly more frequent in PM group and body temperatures were significantly higher in AM group patients. Conclusion: Our study has shown that fasting times in our population is far longer than recommended and fasting prolonged>15 hours is related to a transiently increased cardiac stress and mild hypothermia.

Protein and lipid metabolism adjustments in silver catfish (Rhamdia quelen) during different periods of fasting and refeeding / Ajustes no metabolismo de proteínas e lipídios no jundiá (Rhamdia quelen) durante diferentes períodos de jejum e realimentação

Abstract The fish may experience periods of food deprivation or starvation which produce metabolic changes. In this study, adult Rhamdia quelen males were subjected to fasting periods of 1, 7, 14, and 21 days and of refeeding 2, 4, 6, and 12 days. The results demonstrated that liver protein was depleted after 1 day of fasting, but recovered after 6 days of refeeding. After 14 days of fasting, mobilization in the lipids of the muscular tissue took place, and these reserves began to re-establish themselves after 4 days of refeeding. Plasmatic triglycerides increased after 1 day of fasting, and decreased following 2 days of refeeding. The glycerol in the plasma oscillated constantly during the different periods of fasting and refeeding. Changes in the metabolism of both protein and lipids during these periods can be considered as survival strategies used by R. quelen. The difference in the metabolic profile of the tissues, the influence of the period of fasting, and the type of reserves mobilized were all in evidence.

Resumo Os peixes podem sofrer períodos de privação de alimentos ou de fome, que produzem mudanças metabólicas. Neste estudo, jundiás machos adultos foram submetidos a jejum períodos de 1, 7, 14 e 21 dias e realimentação 2, 4, 6, e 12 dias. Os resultados demonstraram que a proteína do fígado foi esgotada depois de um dia de jejum, mas restabeleceu após 6 dias de realimentação. Após 14 dias de jejum, ocorreu a mobilização dos lípidos no tecido muscular sendo que estas reservas começaram a re-estabelecer-se após 4 dias de realimentação. Os triglicérides plasmáticos aumentam após um dia de jejum, e diminuiram após 2 dias de realimentação. O glicerol no plasma oscilou constantemente durante os diferentes períodos de jejum e realimentação. As alterações no metabolismo de proteína e lipídios durante estes períodos podem ser consideradas uma estratégias de sobrevivência utilizada pelo Rhamdia quelen. Sendo que a diferença no perfil metabólico tecidual bem como a influência do período de jejum e o tipo de reserva a ser mobilizada foram observadas neste estudo.

Fasting/Refeeding Cycles Prevent Myocardial Dysfunction and Morphology Damage in the Spontaneously Hypertensive Rats / Ciclos de Jejum/Realimentação Previnem Disfunção Miocárdica e Danos Morfológicos em Ratos Espontaneamente Hipertensos

Abstract Background: Caloric restriction is known to impair the cardiac function and morphology in hypertrophied hearts of spontaneously hypertensive rats (SHR); however, the influence of fasting/refeeding (RF) is unknown. Objective: To investigate the fasting/refeeding approach on myocardial remodeling and function. In addition, the current study was designed to bring information regarding the mechanisms underlying the participation of Ca2+ handling and b-adrenergic system. Methods: Sixty-day-old male SHR rats were submitted to food ad libitum (C), 50% food restriction (R50) or RF cycles for 90 days. Cardiac remodeling was assessed by ultrastructure analysis and isolated papillary muscle function. The level of significance considered was 5% (a = 0.05). Results: The RF rats presented lower cardiac atrophy than R50 in relation to C rats. The C rats increased weight gain, R50 maintained their initial body weight and RF rats increased and decreased weight during RF. The RF did not cause functional impairment because the isotonic and isometric parameters showed similar behavior to those of C. The isotonic and isometric cardiac parameters were significantly elevated in RF rats compared to R50 rats. In addition, the R50 rats had cardiac damage in relation to C for isotonic and isometric variables. While the R50 rats showed focal changes in many muscle fibers, the RF rats displayed mild alterations, such as loss or disorganization of myofibrils. Conclusion: Fasting/refeeding promotes cardiac beneficial effects and attenuates myocardial injury caused by caloric restriction in SHR rats, contributing to reduce the cardiovascular risk profile and morphological injuries. Furthermore, RF promotes mild improvement in Ca2+ handling and b-adrenergic system.

Resumo Fundamento: A restrição calórica compromete a função e a morfologia cardíacas em corações hipertrofiados de ratos espontaneamente hipertensos (SHR). No entanto, a influência de ciclo de jejum/Realimentação é desconhecida. Objetivo: Investigar o efeito de ciclos de jejum/realimentação sobre a remodelação e função miocárdica. Além disso, o presente estudo foi desenhado para avaliar os mecanismos subjacentes à participação do trânsito de cálcio (Ca+2) e sistema beta-adrenérgico. Métodos: Neste estudo, SHR machos de 60 dias de idade foram submetidos a alimento ad libitum (grupo C), 50% de restrição alimentar (grupo R50) ou ciclos de RF (grupo RF) por 90 dias. A remodelação cardíaca foi avaliada por meio da análise ultraestrutural e função do músculo papilar isolado. Adotou-se o nível de significância de 5% (a = 0,05). Resultados: Os ratos do grupo RF apresentaram menor atrofia cardíaca do que os do grupo R50 em relação aos do grupo C. Os ratos do grupo C aumentaram peso corporal, os ratos do grupo R50 mantiveram seu peso corporal inicial e os ratos do grupo RF aumentaram e reduziram seu peso durante o ciclo RF. O ciclo RF não causou comprometimento funcional, pois os parâmetros isotônicos e isométricos apresentaram comportamento similar aos dos ratos do grupo C. Os parâmetros cardíacos isotônicos e isométricos mostraram-se significativamente elevados nos ratos do grupo RF em comparação aos dos ratos do grupo R50. Além disso, os ratos do grupo R50 apresentaram dano cardíaco em comparação aos ratos do grupo C quanto às variáveis isotônicas e isométricas. Os ratos do grupo R50 apresentaram alterações focais em muitas fibras musculares, enquanto os ratos do grupo RF apresentaram leves alterações, como perda ou desorganização de miofibrilas. Conclusão: Ciclos de Jejum/Realimentação promovem efeitos benéficos cardíacos e atenuam o dano miocárdico causado por restrição calórica em SHR, contribuindo para reduzir o risco cardiovascular e os danos morfológicos. Além disso, o ciclo de jejum/realimentação promove leve melhora do trânsito do Ca2+ e do sistema beta-adrenérgico.

Performance during a strenuous swimming session is associated with high blood lactate: pyruvate ratio and hypoglycemia in fasted rats

The aim of this study was to investigate the effect of lactatemia elevation and glycemia reduction on strenuous swimming performance in fasted rats. Three rats were placed in a swimming tank at the same time. The first rat was removed immediately (control group) and the remaining ones were submitted to a strenuous swimming session. After the second rat was exhausted (Exh group), the third one was immediately removed from the water (Exe group). According to the period of time required for exhaustion, the rats were divided into four groups: low performance (3-7 min), low-intermediary performance (8-12 min), high-intermediary performance (13-17 min), and high performance (18-22 min). All rats were removed from the swimming tanks and immediately killed by decapitation for blood collection or anesthetized for liver perfusion experiments. Blood glucose, lactate, and pyruvate concentrations, blood lactate/pyruvate ratio, and liver lactate uptake and its conversion to glucose were evaluated. Exhaustion in low and low-intermediary performance were better associated with higher lactate/pyruvate ratio. On the other hand, exhaustion in high-intermediary and high performance was better associated with hypoglycemia. Lactate uptake and glucose production from lactate in livers from the Exe and Exh groups were maintained. We concluded that there is a time sequence in the participation of lactate/pyruvate ratio and hypoglycemia in performance during an acute strenuous swimming section in fasted rats. The liver had an important participation in preventing hyperlactatemia and hypoglycemia during swimming through lactate uptake and its conversion to glucose.

Autophagy and intermittent fasting: the connection for cancer therapy?

Cancer is a leading cause of death worldwide, and its incidence is continually increasing. Although anticancer therapy has improved significantly, it still has limited efficacy for tumor eradication and is highly toxic to healthy cells. Thus, novel therapeutic strategies to improve chemotherapy, radiotherapy and targeted therapy are an important goal in cancer research. Macroautophagy (herein referred to as autophagy) is a conserved lysosomal degradation pathway for the intracellular recycling of macromolecules and clearance of damaged organelles and misfolded proteins to ensure cellular homeostasis. Dysfunctional autophagy contributes to many diseases, including cancer. Autophagy can suppress or promote tumors depending on the developmental stage and tumor type, and modulating autophagy for cancer treatment is an interesting therapeutic approach currently under intense investigation. Nutritional restriction is a promising protocol to modulate autophagy and enhance the efficacy of anticancer therapies while protecting normal cells. Here, the description and role of autophagy in tumorigenesis will be summarized. Moreover, the possibility of using fasting as an adjuvant therapy for cancer treatment, as well as the molecular mechanisms underlying this approach, will be presented.

Fasting: a major limitation for resistance exercise training effects in rodents

Protocols that mimic resistance exercise training (RET) in rodents present several limitations, one of them being the electrical stimulus, which is beyond the physiological context observed in humans. Recently, our group developed a conditioning system device that does not use electric shock to stimulate rats, but includes fasting periods before each RET session. The current study was designed to test whether cumulative fasting periods have some influence on skeletal muscle mass and function. Three sets of male Wistar rats were used in the current study. The first set of rats was submitted to a RET protocol without food restriction. However, rats were not able to perform exercise properly. The second and third sets were then randomly assigned into three experimental groups: 1) untrained control rats, 2) untrained rats submitted to fasting periods, and 3) rats submitted to RET including fasting periods before each RET session. While the second set of rats performed a short RET protocol (i.e., an adaptation protocol for 3 weeks), the third set of rats performed a longer RET protocol including overload (i.e., 8 weeks). After the short-term protocol, cumulative fasting periods promoted loss of weight (P<0.001). After the longer RET protocol, no difference was observed for body mass, extensor digitorum longus (EDL) morphology or skeletal muscle function (P>0.05 for all). Despite no effects on EDL mass, soleus muscle displayed significant atrophy in the fasting experimental groups (P<0.01). Altogether, these data indicate that fasting is a major limitation for RET in rats.

Are people who have a better smell sense, more affected from satiation? / As pessoas que têm melhor olfato são mais afetadas pela saciedade?

Abstract Introduction: The olfactory system is affected by the nutritional balance and chemical state of the body, serving as an internal sensor. All bodily functions are affected by energy loss, including olfaction; hunger can alter odour perception. Objective: In this study, we investigated the effect of fasting on olfactory perception in humans, and also assessed perceptual changes during satiation. Methods: The "Sniffin' Sticks" olfactory test was applied after 16 h of fasting, and again at least 1 h after Ramadan supper during periods of satiation. All participants were informed about the study procedure and provided informed consent. The study protocol was approved by the local Ethics Committee of Gaziosmanpaşa Taksim Education and Research Hospital (09/07/2014 no: 60). The study was conducted in accordance with the basic principles of the Declaration of Helsinki. Results: This prospective study included 48 subjects (20 males, 28 females) with a mean age of 33.6 ± 9.7 (range 20-72) years; their mean height was 169.1 ± 7.6 (range 150.0-185.0) cm, mean weight was 71.2 ± 17.6 (range 50.0-85.0) kg, and average BMI was 24.8 ± 5.3 (range 19.5-55.9). Scores were higher on all items pertaining to olfactory identification, thresholds and discrimination during fasting vs. satiation (p < 0.05). Identification (I) results: Identification scores were significantly higher during the fasting (median = 14.0) vs. satiation period (median = 13.0). Threshold (T) results: Threshold scores were significantly higher during the fasting (median = 7.3) vs. satiation period (median = 6.2). Discrimination (D) results: Discrimination scores were significantly higher during the fasting (median = 14.0) vs. satiation period (median = 13.0). The total TDI scores were 35.2 (fasting) vs. 32.6 (satiation). When we compared fasting threshold value of >9 and ≤9, the gap between the fasting and satiety thresholds was significantly greater in >9 (p < 0.05). Conclusion: Olfactory function improved during fasting and declined during satiation. The olfactory system is more sensitive, and more reactive to odours, under starvation conditions, and is characterised by reduced activity during satiation. This situation was more pronounced in patients with a better sense of smell. Olfaction-related neurotransmitters should be the target of further study.

Resumo Introdução: O sistema olfatório é afetado pelo equilíbrio nutricional e estado químico do corpo, que serve como um sensor interno. Todas as funções corporais são afetadas pela perda de energia, inclusive o olfato; a fome pode alterar a percepção do odor. Objetivo: Neste estudo, investigamos o efeito do jejum sobre a percepção olfativa em seres humanos, e também avaliamos as mudanças de percepção durante a saciedade. Método: O teste olfatório Sniffin Sticks foi aplicado após 16 horas de jejum e novamente pelo menos 1 hora após a ceia do Ramadã durante os períodos de saciedade. Todos os participantes foram informados sobre os procedimentos do estudo e forneceram o consentimento informado. O protocolo do estudo foi aprovado pelo Comitê de Ética do Gaziosmanpaşa Taksim Education e Research Hospital (2014/09/07 n° 60). O estudo foi conduzido de acordo com os princípios básicos da Declaração de Helsinki. Resultados: Foram incluídos 48 pacientes (20 homens, 28 mulheres) com média de 33,6 ± 9,7 aos (variação 20-72); a altura média deles era de 169,1 ± 7,6 cm (variação 150-185), o peso médio era de 71,2 ± 17,6 kg (variação de 50-85) e o IMC médio era de 24,8 ± 5,3 (variação de 19,5-55,9). Os escores foram maiores em todos os itens correspondentes à identificação olfativa, limiares e discriminação durante jejum vs. saciedade (p < 0,05). Resultados da identificação (I): os escores de identificação foram significativamente maiores durante o jejum (mediana = 14) vs. período de saciedade (mediana = 13). Resultados limiares (T): os escores limiares foram significativamente maiores durante o jejum (mediana = 7,3) vs. período de saciedade (mediana = 6,2). Resultados de discriminação (D): os escores de discriminação foram significativamente maiores durante o jejum (mediana = 14) vs. período de saciedade (mediana = 13). Os escores totais de TDI foram de 35,2 (jejum) vs. 32,6 (saciedade). Quando comparamos o valor do limiar de jejum de > 9 e ≤ 9, a diferença entre os limiares de jejum e de saciedade foi significativamente maior em > 9 (p < 0,05). Conclusão: A função olfatória melhorou durante o jejum e diminuiu durante a saciedade. O sistema olfatório é mais sensível e mais reativo aos odores em condições de fome e é caracterizado por atividade reduzida durante a saciedade. Essa situação foi mais pronunciada em pacientes com um melhor sentido olfativo. Os neurotransmissores relacionados com o olfato devem ser alvo de um estudo mais aprofundado.

Hypertriglyceridemic Waist Phenotype and Changes in the Fasting Glycemia and Blood Pressure in Children and Adolescents Over One-Year Follow-Up Period / Fenótipo Cintura Hipertrigliceridêmica e mudanças na glicemia de jejum e pressão arterial de crianças e adolescentes após um ano de seguimento

Abstract Background: The hypertriglyceridemic waist (HTW) phenotype is defined as the simultaneous presence of increased waist circumference (WC) and serum triglycerides (TG) levels and it has been associated with cardiometabolic risk in children and adolescents. Objective: The objective was to evaluate the influence of HTW phenotype in the fasting glycemia and blood pressure in children and adolescents over one-year follow-up period. Methods: It is a cohort study involving 492 children and adolescents from 7 to 15 years old, both genders, who were submitted to anthropometric, biochemical and clinical evaluation at the baseline, and also after 6 and 12 months of follow-up. Generalized Estimating Equation (GEE) models were calculated to evaluate the longitudinal influence of the HTW phenotype in the glycemia and blood pressure over one-year. Results: It was observed a prevalence of 10.6% (n = 52) of HTW phenotype in the students. The GEE models identified that students with HTW phenotype had an increase of 3.87 mg/dl in the fasting glycemia mean (CI: 1.68-6.05) and of 3.67mmHg in the systolic blood pressure (SBP) mean (CI: 1.55-6.08) over one-year follow-up, after adjusting for confounding variables. Conclusions: The results of this study suggest that HTW phenotype is a risk factor for longitudinal changes in glycemia and SBP in children and adolescents over one-year follow-up period.

Resumo Fundamento: O fenótipo de cintura hipertrigliceridêmica (CHT) é definido como a presença simultânea de circunferência de cintura (CC) e níveis séricos de triglicérides (TG) aumentados e tem sido associado com risco cardiometabólico em crianças e adolescentes. Objetivo: Avaliar a influência do fenótipo CHT na glicemia de jejum e na pressão arterial em crianças e adolescentes em um período de acompanhamento de um ano. Métodos: Trata-se de um estudo de coorte envolvendo 492 crianças e adolescentes de 7 a 15 anos de ambos os sexos, que foram submetidos à avaliação antropométrica, bioquímica e clínica no início e também após 6 e 12 meses de seguimento. Os modelos de Equação de Estimulação Generalizada (GEE) foram calculados para avaliar a influência longitudinal do fenótipo CHT na glicemia e na pressão arterial ao longo de um ano. Resultados: Foi observada uma prevalência de 10,6% (n = 52) do fenótipo CHT nos estudantes. Os modelos GEE identificaram que os estudantes com fenótipo CHT apresentaram aumento de 3,87 mg/dl na média de glicemia em jejum (IC: 1,68-6,05) e de 3,67 mmHg na pressão arterial sistólica media (PAS) (IC: 1,55-6,08) depois de um ano de acompanhamento, após ajuste para variáveis de confusão. Conclusões: Os resultados deste estudo sugerem que o fenótipo CHT é um fator de risco para alterações longitudinais da glicemia e da PAS em crianças e adolescentes em um período de um ano de seguimento.

Effects of intermittent fasting on metabolism in men / Efeitos do jejum intermitente no metabolismo humano

This review analyzes the available literature on the impact of intermittent fasting (IF), a nutritional intervention, on different aspects of metabolism. The epidemic of metabolic disturbances, such as obesity, metabolic syndrome (MS), and diabetes mellitus type 2 has led to an increase in the prevalence of cardiovascular diseases, and affected patients might significantly benefit from modifications in nutritional habits. Recent experimental studies have elucidated some of the metabolic mechanisms involved with IF. Animal models have shown positive changes in glucose (lower plasma glucose and insulin levels) and in lipid metabolism (reduced visceral fat tissue and increased plasma adiponectin level), and an increased resistance to stress. Despite the limited number of samples studied, positive results have been reported on the impact of IF for human health. IF is reported to improve the lipid profile; to decrease inflammatory responses, reflected by changes in serum adipokine levels; and to change the expression of genes related to inflammatory response and other factors. Studies on obese individuals have shown that patient compliance was greater for IF than other traditional nutritional approaches (calorie restriction), and IF was found to be associated with low oxidative stress. Recent reports suggest that IF exerts a positive impact on the metabolic derangements commonly associated with cardiovascular diseases, and that it may be a viable and accessible intervention for most individuals. Therefore, further clinical studies are essential to test the effectiveness of IF in preventing and controlling metabolic and cardiovascular diseases.

Esta revisão traz uma análise de dados disponíveis na literatura sobre o impacto do jejum intermitente, uma modalidade de intervenção nutricional, em diferentes aspectos do metabolismo. A epidemia de anormalidades metabólicas, como obesidade, síndrome metabólica e diabetes mellitus tipo 2, tem ocasionado um aumento na prevalência de doenças cardiovasculares, condições em que os indivíduos afetados apresentam impor tantes melhorias advindas de modificação nos hábitos alimentares. Estudos experimentais recentes têm elucidado a modulação do metabolismo por jejum intermitente. Testes com animais têm mostrado alterações positivas no metabolismo glicídico (valores menores de glicemia e insulinemia) e lipídico (redução no volume de gordura visceral e aumento nos valores de adiponectina plasmática), além de uma maior resistência ao estresse. Apesar dos estudos disponíveis apresentarem populações muito reduzidas, observaram-se resultados positivos com esta intervenção também na saúde humana. Os resultados indicam melhorias no perfil lipídico, redução de respostas inflamatórias, com redução na liberação de adipocinas inflamatórias e alterações na expressão de genes relacionados com a resposta inflamatória e de outros fatores. Em indivíduos obesos observou-se uma melhor adesão ao jejum intermitente em relação a intervenções tradicionais (restrição calórica), além da redução no estresse oxidativo desta população. Dessa maneira, por se tratar de uma intervenção viável e acessível para a maioria dos indivíduos, novos estudos clínicos são necessários para testar a eficácia desta intervençãonaprevenção e no controle de doenças metabólicas e cardiovasculares.

Ajustes endocrino-metabólicos durante el ayuno de Ramadán en jóvenes deportistas / Endocrine-metabolic adjustments during Ramadan fasting in young athletes

El precepto islámico del Ramadán (R), implica importantes modificaciones fisiológicas debido a las restricciones hídricas y dietéticas a lo largo del día y durante un mes, lo que tiene una especial repercusión física e intelectual de los musulmanes, particularmente en sociedades occidentales, en las que no se producen reajustes horarios para las actividades cotidianas. Entre las modificaciones impuestas por el R, el ayuno intermitente día/noche, desencadena mecanismos de adaptación para rentabilizar el consumo energético. El objetivo del presente estudio ha sido valorar algunos cambios endocrinometabólicos que acontecen a lo largo de la jornada, durante el mes de ayuno, en jóvenes que tienen que continuar con su actividad y entrenamiento deportivo habitual. Diez jóvenes musulmanes, varones, sanos, sometidos a entrenamiento deportivo, con edades entre 18 y 25 años que realizaron el R. Se analizaron parámetros bioquímicos y hormonales en plasma, una semana previa al R, primera y cuarta del periodo de ayuno (mañana y tarde) y semana posterior. Durante el R, se observa un descenso de los parámetros bioquímicos a lo largo del día, especialmente de la glucemia, siendo estos cambios más evidentes en la primera semana. La concentración de cortisol se encuentran significativamente elevada durante todo el mes, como consecuencia del cambio de ritmo circadiano de secreción. El R obliga al organismo a un ajuste endocrino-metabólico con el fin de preservar la eficiencia energética durante la jornada. Este control se vuelve más eficaz conforme avanza el mes de ayuno y la consecuente adaptación fisiológica.

The Islamic precept of R implies important physiological modifications due to the hydric and dietetic restrictions along a whole month plus a day, all of which have a crucial repercussion over the physical and intellectual performance of Muslims, particularly in occidental societies, in which there is no hour readjustments for daily activities. Among the imposed modifications by Ramadan in daily habits, intermittent fasting along day and night causes adaptation mechanisms to optimize the energy consumption. The objective of this study was to analyze the metabolic-endocrine changes that happen during daily working hours, along the month of fasting in young subjects who have to continue their usual activities and sport training. Ten young muslim subjects, male, healthy, set to sport training, ages in between 18 and 25 who completed Ramadan. Plasma biochemical and hormonal parameters were analyzed in plasma, a week before Ramadan, in the first and fourth of the fasting month and a week after conclusion. During Ramadan, have been observed a drop of biochemical parameters along daytime, especially those related to glycemia, being these changes stronger in the first week. The concentration of cortisol found to be significantly high during the whole month as a consequence of adaptation to the change of circadian secretion rhythms. Ramadan obliges subject´s organisms to readjust their endocrine and metabolic system in order to preserve the energetic efficiency during daytime. This auto control becomes more efficient as long as the month advances due to physiological adaptations.

Leptina e grelina na regulação do comportamento alimentar da tartaruga Eretmochelys imbricata (Linnaeus 1766) / Leptin and ghrelin regulates the feeding behavior of the sea turtle Eretmochelys imbricata (Linnaeus, 1766)

Durante a temporada de nidação, fêmeas de tartarugas marinhas costumam reduzir ou cessar por completo a ingestão de alimentos. Este fato sugere que o armazenamento de energia e nutrientes para a reprodução ocorra durante o período que antecede a migração para os sítios reprodutivos, enquanto estes animais ainda se encontram nas áreas de alimentação. Do ponto de vista fisiológico, tartarugas em atividade reprodutiva são capazes de permanecer longos períodos em jejum. Fatores neuroendócrinos vêm sendo recentemente apontados como os mais relevantes para a manutenção da homeostase energética de todos os vertebrados; entre eles, a leptina (hormônio anorexígeno) e a grelina (peptídeo orexígeno). Com o objetivo de compreender o mecanismo de fome e saciedade nas tartarugas marinhas, investigamos os níveis séricos destes hormônios e de outros indicadores nutricionais em fêmeas de Eretmochelys imbricata desovando no litoral do Rio Grande do Norte, Brasil. Foram coletadas amostras de sangue de 41 tartarugas durante as temporadas reprodutivas de 2010/2011 e 2011/2012. Os níveis séricos de leptina diminuíram significativamente ao longo do período de nidação, de modo a explicar a busca por alimentos ao término da temporada. Ao mesmo tempo, registramos uma tendência crescente nos níveis séricos de grelina, fator este que também justifica a remigração para as áreas de alimentação no fim do período. Não foram observadas tendências lineares para alguns dos parâmetros avaliados, entre eles: hematócrito, alanina aminotransferase (ALT), aspartato aminotransferase (AST), fosfatase alcalina (FA), gama glutamil transferase (GGT), lipoproteínas de baixa densidade (LDL) e lipoproteínas de alta densidade (HDL). É possível que a maior parte dos indicadores nutricionais tenha apresentado redução gradativa devido ao estresse fisiológico decorrente da vitelogênese e de repetidas oviposições. No entanto, é valido ressaltar que o quadro de restrição calórica por tempo prolongado ...

Reproductive female sea turtles rarely have been observed foraging during the nesting season. This suggests that prior to their reproductive migration to nesting beaches, the adult females must store sufficient energy and nutrients at their foraging grounds, and must be physiologically capable of undergoing months without feeding. Leptin (an appetite-suppressing protein) and ghrelin (a hunger-stimulating peptide) affect body weight by influencing energy intake in all vertebrates. We investigated the levels of these hormones and other physiological and nutritional parameters in nesting female hawksbill sea turtles in Rio Grande do Norte State, Brazil, by collecting consecutive blood samples from 41 turtles during the 2010/2011 and 2011/2012 reproductive seasons. We found that levels of serum leptin decreased over the nesting season, which potentially relaxed appetite suppression and led females to begin foraging either during or after the post-nesting migration. Concurrently, we recorded an increasing trend in ghrelin, which stimulated appetite towards the end of the nesting season. Both findings are consistent with the prediction that post-nesting females will begin to forage, either during or just after their post-nesting migration. We observed no seasonal trend for other physiological parameters: PCV values, alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), gamma glutamyl transferase (GGT) low-density lipoprotein (LDL) and high-density lipoprotein (HDL) serum levels. The observed downward trends in general serum biochemistry levels were likely due to the physiological stress of vitellogenesis and nesting in addition to limited energy resources and probable fasting

Resultados clínicos e metabólicos da abreviação do jejum com carboidratos na revascularização cirúrgica do miocárdio / Clinical and metabolic results of fasting abbreviation with carbohydrates in coronary artery bypass graft surgery

INTRODUÇÃO: Existe pouca informação sobre abreviação do jejum pré-operatório com oferta de líquidos ricos em carboidratos (CHO) nas operações cardiovasculares. OBJETIVOS: Avaliar variáveis clínicas, segurança do método e efeitos no metabolismo de pacientes submetidos à abreviação do jejum na cirurgia de revascularização do miocárdio (CRVM). MÉTODOS: Quarenta pacientes submetidos à CRVM foram randomizados para receberem 400 ml (6 horas antes) e 200 mL (2 horas antes) de maltodextrina a 12,5% (Grupo I, n=20) ou apenas água (Grupo II, n=20) antes da indução anestésica. Foram avaliadas diversas variáveis clínicas no perioperatório e também a resistência insulínica (RI) pelo índice de Homa-IR e pela necessidade de insulina exógena; além da função excretora da célula beta pancreática pelo Homa-Beta e controle glicêmico por exames de glicemia capilar. RESULTADOS: Não ocorreram óbitos, broncoaspiração, mediastinite, infarto agudo do miocárdio ou acidente vascular encefálico perioperatórios. Fibrilação atrial ocorreu em dois pacientes de cada grupo e complicações infecciosas não diferiram entre os grupos (P=0,611). Pacientes do Grupo I apresentaram dois dias a menos de internação hospitalar (P=0,025) e um dia a menos na UTI (P<0,001). O tempo de uso de dobutamina foi menor no Grupo I (P=0,034). Houve pior controle glicêmico nas primeiras 6 horas de pós-operatório no Grupo II (P=0,012). RI foi constatada e não diferiu entre os grupos (P>0,05). Declínio da produção endógena de insulina ocorreu em ambos os grupos (P<0,001). CONCLUSÃO: Abreviação do jejum pré-operatório com oferta de CHO na CRVM foi segura, melhorou o controle glicêmico na UTI, diminuiu tempo de uso de dobutamina, e de internação hospitalar e na UTI. Contudo, não influenciou a RI e morbimortalidade de fase hospitalar.

INTRODUCTION: Limited information is available about preoperative fasting abbreviation with administration of liquid enriched with carbohydrates (CHO) in cardiovascular surgeries. OBJECTIVES: To evaluate clinical variables, security of the method and effects on the metabolism of patients undergoing fasting abbreviation in coronary artery bypass graft (CABG) surgery. METHODS: Forty patients undergoing CABG were randomized to receive 400 ml (6 hours before) and 200 ml (2 hours before) of maltodextrin at 12.5% (Group I, n=20) or just water (Group II, n=20) before anesthetic induction. Perioperative clinical variables were evaluated. Insulin resistance (IR) was evaluated by Homa-IR index and also by the need of exogenous insulin; pancreatic beta-cell excretory function by Homa-Beta index and glycemic control by tests of capillary glucose. RESULTS: Deaths, bronchoaspiration, mediastinitis, stroke and acute myocardial infarction did not occur. Atrial fibrillation occurred in two patients of each group and infectious complications did not differ among groups (P=0.611). Patients of Group I presented two days less of hospital stay (P=0.025) and one day less in the ICU (P<0.001). The length of time using dobutamine was shorter in Group I (P=0.034). Glycemic control in the first 6h after surgery was worse for Group II (P=0.012). IR was verified and did not differ among groups (P>0.05). A decline in the endogenous production of insulin was observed in both groups (P<0.001). CONCLUSION: Preoperative fasting abbreviation with the administration of CHO in the CABG was safe. The glycemic control improved in the ICU; there was less time in the use of dobutamine and length of hospital and ICU stay was reduced. However, neither IR nor morbimortality during hospital phase were influenced.

Different Response of Body Weight Change According to Ketonuria after Fasting in the Healthy Obese

The relationship between obesity and ketonuria is not well-established. We conducted a retrospective observational study to evaluate whether their body weight reduction response differed by the presence of ketonuria after fasting in the healthy obese. We used the data of 42 subjects, who had medical records of initial urinalysis at routine health check-up and follow-up urinalysis in the out-patient clinic, one week later. All subjects in the initial urinalysis showed no ketonuria. However, according to the follow-up urinalysis after three subsequent meals fasts, the patients were divided into a non-ketonuria group and ketonuria group. We compared the data of conventional low-calorie diet programs for 3 months for both groups. Significantly greater reduction of body weight (-8.6 +/- 3.6 kg vs -1.1 +/- 2.2 kg, P < 0.001), body mass index (-3.16 +/- 1.25 kg/m2 vs -0.43 +/- 0.86 kg/m2, P < 0.001) and waist circumference (-6.92 +/- 1.22 vs -2.32 +/- 1.01, P < 0.001) was observed in the ketonuria group compared to the non-ketonuria group. Fat mass and lean body mass were also more reduced in the ketonuria group. In addition, serum free fatty acid concentration after intervention in the ketonuria group showed significant more increment than in the non-ketonuria group. The presence of ketonuria after fasting may be a predicting factor of further body weight reduction.