249 research outputs found

    Sucrose activates human taste pathways differently from artificial sweetener

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    Animal models suggest that sucrose activates taste afferents differently than non-caloric sweeteners. Little information exists how artificial sweeteners engage central taste pathways in the human brain. We assessed sucrose and sucralose taste pleasantness across a concentration gradient in 12 healthy control women and applied 10% sucrose and matched sucralose during functional magnet resonance imaging. The results indicate that (1) both sucrose and sucralose activate functionally connected primary taste pathways; (2) taste pleasantness predicts left insula response; (3) sucrose elicits a stronger brain response in the anterior insula, frontal operculum, striatum and anterior cingulate, compared to sucralose; (4) only sucrose, but not sucralose, stimulation engages dopaminergic midbrain areas in relation to the behavioral pleasantness response. Thus, brain response distinguishes the caloric from the non-caloric sweetener, although the conscious mind could not. This could have important implications on how effective artificial sweeteners are in their ability to substitute sugar intake

    COMMONLY USED ARTIFICIAL SWEETENERS IN EUROPE

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    It has been known for many years that the excessive consumption of sugar (sucrose) has harmful effects on human health. This fact led to a reduction in sugar consumption and the appearance of artificial sweeteners in the 1800s. The first low-cost and low-calorie sugar alternative was saccharin. Since this sweetener gained great popularity, other artificial sweeteners soon followed, including aspartame, acesulfame-K and cyclamates as the most common ones. As the result of a sharp rise in the obesity pandemic in all populations and ethnic groups, a demand for sweeteners with a minimum caloric value has increased dramatically in the last decade as consumers care more about their health. Due to the different regulation of permitted artificial sweeteners in United States (US) and Europe (EU), there are some controversies and suspicions about the relationship between certain sweeteners and a potential health risk. Despite doubts about the safety of artificial sweeteners, many studies have shown the absence of dangers associated with their use (if used in the acceptable daily intake, ADI). Therefore, artificial sweeteners today are considered as safe for consumption by many competent institutions and organisations. Nowadays, artificial sweeteners are fundamental in the food industry and present in many foodstuffs

    Soft drinks and sweeteners intake: Possible contribution to the development of metabolic syndrome and cardiovascular diseases. Beneficial or detrimental action of alternative sweeteners?

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    Abstract The rapid increase in obesity, metabolic syndrome, and cardiovascular diseases (CVDs) has been related to the rise in sugar-added foods and sweetened beverages consumption. An interesting approach has been to replace sugar with alternative sweeteners (AS), due to their impact on public health. Preclinical and clinical studies, which analyze the safety of AS intake, are still limited. Major pathogenic mechanisms of these substances include ROS and AGEs formation. Indeed, endothelial dysfunction involving in the pathogenesis of micro- and macro-vascular diseases is mitochondrial dysfunction dependent. Hyperglycemia and endoplasmic reticulum stress together produce ROS, contributing to the development and progression of cardiovascular complications during type 2 diabetes (T2D), thus causing oxidative changes and direct damage of lipids, proteins, and DNA. Epidemiological studies in healthy subjects have suggested that the consumption of artificial AS can promote CV complications, such as glucose intolerance and predisposition to the onset of T2D, whereas natural AS could reduce hyperglycemia, improve lipid metabolism and have antioxidant effects. Long-term prospective clinical randomized studies are needed to evaluate precisely whether exposure to alternative sugars can have clinical implications on natural history and clinical outcomes, especially in children or during the gestational period through breast milk

    COMMONLY USED ARTIFICIAL SWEETENERS IN EUROPE

    Get PDF
    It has been known for many years that the excessive consumption of sugar (sucrose) has harmful effects on human health. This fact led to a reduction in sugar consumption and the appearance of artificial sweeteners in the 1800s. The first low-cost and low-calorie sugar alternative was saccharin. Since this sweetener gained great popularity, other artificial sweeteners soon followed, including aspartame, acesulfame-K and cyclamates as the most common ones. As the result of a sharp rise in the obesity pandemic in all populations and ethnic groups, a demand for sweeteners with a minimum caloric value has increased dramatically in the last decade as consumers care more about their health. Due to the different regulation of permitted artificial sweeteners in United States (US) and Europe (EU), there are some controversies and suspicions about the relationship between certain sweeteners and a potential health risk. Despite doubts about the safety of artificial sweeteners, many studies have shown the absence of dangers associated with their use (if used in the acceptable daily intake, ADI). Therefore, artificial sweeteners today are considered as safe for consumption by many competent institutions and organisations. Nowadays, artificial sweeteners are fundamental in the food industry and present in many foodstuffs

    A Literature Review of the Prevalence, Metabolism, and Usage Guidelines of Non-nutritive Sweeteners

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    Due to their reputation for being a healthier option to traditional table sugar, non-nutritive sweeteners have garnered popularity, particularly with those affected by type II diabetes mellitus (DM2) or obesity. A literature review on the characteristics, metabolism, and optimal cooking guidelines of non-nutritive sweeteners was performed to establish more knowledge about these trending food additives. The literature review indicates that the presence of non-nutritive sweeteners (NNS) may influence glucose metabolism by binding T1R2/T1R3 sweetness receptors present throughout the gastrointestinal tract. However, not all studies showed positive correlations. Though inconclusive, the studies suggest a possible connection between excessive NNS consumption and impaired glucose metabolism, but moderate consumption appears to have no significant effect

    The role of sweet taste in satiation and satiety

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    Increased energy consumption, especially increased consumption of sweet energy-dense food, is thought to be one of the main contributors to the escalating rates in overweight individuals and obesity globally. The individual\u27s ability to detect or sense sweetness in the oral cavity is thought to be one of many factors influencing food acceptance, and therefore, taste may play an essential role in modulating food acceptance and/or energy intake. Emerging evidence now suggests that the sweet taste signaling mechanisms identified in the oral cavity also operate in the gastrointestinal system and may influence the development of satiety. Understanding the individual differences in detecting sweetness in both the oral and gastrointestinal system towards both caloric sugar and high intensity sweetener and the functional role of the sweet taste system may be important in understanding the reasons for excess energy intake. This review will summarize evidence of possible associations between the sweet taste mechanisms within the oral cavity, gastrointestinal tract and the brain systems towards both caloric sugar and high intensity sweetener and sweet taste function, which may influence satiation, satiety and, perhaps, predisposition to being overweight and obesity

    The convolutional neural network as a tool to classify electroencephalography data resulting from the consumption of juice sweetened with caloric or non-caloric sweeteners

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    Sweetener type can influence sensory properties and consumer’s acceptance and preference for low-calorie products. An ideal sweetener does not exist, and each sweetener must be used in situations to which it is best suited. Aspartame and sucralose can be good substitutes for sucrose in passion fruit juice. Despite the interest in artificial sweeteners, little is known about how artificial sweeteners are processed in the human brain. Here, we applied the convolutional neural network (CNN) to evaluate brain signals of 11 healthy subjects when they tasted passion fruit juice equivalently sweetened with sucrose (9.4 g/100 g), sucralose (0.01593 g/100 g), or aspartame (0.05477 g/100 g). Electroencephalograms were recorded for two sites in the gustatory cortex (i.e., C3 and C4). Data with artifacts were disregarded, and the artifact-free data were used to feed a Deep Neural Network with tree branches that applied a Convolutions and pooling for different feature filtering and selection. The CNN received raw signal as input for multiclass classification and with supervised training was able to extract underling features and patterns from the signal with better performance than handcrafted filters like FFT. Our results indicated that CNN is an useful tool for electroencephalography (EEG) analyses and classification of perceptually similar tastes

    Nutrient postingestive signalling : the asymmetry of the response of dopaminergic neuronal circuits

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    Feeding behaviour encompasses any action an animal performs to obtain and consume food. This complex process is affected by pre and postingestive (PI) signals. The former occurs prior and during food consumption, while the latter are related to the mechanisms that occur once food is swallowed. Both these signals shape food-seeking behaviour and convey important information to the central nervous system (CNS). Currently, it is known that both homeostatic and non-homeostatic circuits, within the CNS, respond to PI stimuli. Homeostatic circuits are controlled by several hypothalamic nuclei. Non-homeostatic circuits are mostly related to the rewarding properties of food and involve dopamine activation and consequent release in the striatum. In fact, several authors have shown that dopamine release in the nucleus accumbens (NAc), a nucleus from the ventral striatum, increases upon PI carbohydrate detection. Additionally, there is robust evidence that PI stimuli from carbohydrates increases neuronal dopaminergic activity in the ventral tegmental area (VTA). Recently, it was described that gut infusions of fat increased dopamine release in the dorsal striatum, However, much less is known about central nervous responses to PI stimuli from other nutrients, such as fat or proteins. On the other hand, the usage of different nutrients to understand PI feedback in feeding behaviour has been extensively studied using classical associative learning. There is clear evidence that animals prefer flavours paired with calories, carbohydrates, fat or proteins, to flavours paired with non-nutritive solutions. This indicates that the reinforcing properties of PI stimuli could be associated, mostly, to the caloric content of food. Therefore, the hypothesis for this work is that dopaminergic neurons increase their activity when caloric solutions are infused directly into the stomach. More specifically, it is postulated that ventral areas of dopaminergic neurons will increase their activity when carbohydrates are infused, while intragastric (IG) lipids infusion will activate a more dorsal area of dopaminergic neurons activating substantia nigra dopaminergic neurons and dopamine release in dorsal striatum. To test this hypothesis, this work focused on how dopaminergic neurons respond to different IG nutrient infusions and how PI feedback affects dopamine response in ventral and dorsal striatal and dopaminergic regions. Thus, calcium imaging and fibre photometry experiments were carried out in dopaminergic regions - VTA and substantia nigra pars compacta (SNc) - and striatal regions - NAc and dorsal-lateral striatum (DLS) -, respectively, while isocaloric solutions of fat and sucrose were infused directly into the stomach. Additionally, how PI stimuli impacts a reinforcement learning (RL) probabilistic behavioural task was also studied. For this, a novel two-action probabilistic instrumental task was developed to better asses how PI feedback modulates learning based on IG infusions of sucrose (caloric carbohydrate) or sucralose (non-caloric artificial sweetener) and how different reward probabilities can affect this type of behaviour. Calcium imaging recordings revealed that the VTA responds specifically to sucrose, when compared to corn oil or a non-caloric artificial sweetener - sucralose. SNc responses were not nutrient-specific, since dopaminergic activity in this nucleus showed similar patterns of response for all the reinforcers tested. Evaluation of dopamine release in ventral and the dorsal striatum, simultaneously and in the same animal, corroborated previous evidence that dopamine release in the NAc increases when sucrose is infused. In opposition, DLS did not respond to any of the reinforcers administered. Additionally, preliminary data showed that dopaminergic SNc responses did not depend on the lipid administered since response to isocaloric SMOF lipid solution, composed of several types of fatty acids, was similar to corn oil response. Interestingly, NAc response to SMOF lipid was similar to sucrose response, which could mean that ventral response depends on lipid constitution. The development of the instrumental two-action probabilistic task showed that, when given the choice, between a lever associated to IG infusion of a caloric solution and a lever associated to IG infusion of a non caloric solution, mice develop a clear preference for the lever associated with caloric content. This preference was independent of the probability of delivering the reward associated with each lever. Altogether, results from this work shed light on the postulated asymmetry of dopaminergic responses between mesolimbic (VTA to ventral striatum) and nigrostriatal (SNc to dorsal striatum) neuronal pathways, according to the type of postingestive stimuli. Results from the development of the two-action task inferred important parameters in decision making and RL based on PI stimuli.O comportamento alimentar engloba qualquer ação que um animal realiza para obter e consumir comida. Este processo complexo é afetado por sinais pré e pós-ingestivos. Os primeiros ocorrem antes e durante o consumo de comida enquanto os segundos estão relacionados com todos os mecanismos que ocorrem após o consumo da comida. Ambos influenciam o comportamento alimentar e transmitem informações relevantes ao sistema nervoso central (SNC). Atualmente, sabe-se que existem, no SNC, circuitos homeostáticos e não homeostáticos que respondem a estímulos pós-ingestivos. Os circuitos homeostáticos são maioritariamente controlados por núcleos do hipotálamo. Os circuitos não homeostáticos estão maioritariamente relacionados com as propriedades recompensadoras da comida e envolvem ativação e consequente libertação de dopamina no estriado. De facto, vários autores mostraram que a concentração de dopamina no núcleo accumbens (NAc), um núcleo do estriado ventral, aumenta em resposta à deteção pós-ingestiva de carbohidratos. Também há evidência de que estímulos pós-ingestivos derivados da deteção de carbohidratos levam a um aumento de atividade dopaminérgica neuronal na área ventral tegmental (AVT). Recentemente, foi ainda descrito que infusões de lípidos no intestino levaram ao aumento de dopamina no estriado dorsal. Contudo, a resposta dopaminérgica a estímulos pós-ingestivos com o mesmo conteúdo calórico, mas de proveniência nutricional diferente continua por explorar. Por outro lado, mecanismos pós-ingestivos com diferentes tipos de nutrientes foi extensivamente explorado através de paradigmas clássicos de aprendizagem de associação. Há várias evidências de que animais preferem sabores associados a infusão de substâncias calorias quando comparado com sabores associados a soluções não-nutritivas, o que parece indicar que estímulos pós-ingestivos dependentes do conteúdo calórico parecem ativar regiões neuronais de recompensa que explicam as preferências comportamentais. Assim a hipótese para o trabalho descrito é de que neurónios dopaminérgicos aumentam a sua atividade quando soluções calóricas são administradas diretamente no estômago. Mais especificamente, foi postulado que neurónios dopaminérgicos de áreas centrais ventrais aumentam a sua atividade quando carbohidratos são administrados, enquanto lípidos devem ativar neurónios dopaminérgicos de áreas mais dorsais, levando a ativação da substância negra pars compacta e estriado dorsal. Tendo em conta o descrito, este trabalho focou-se em perceber como neurónios dopaminérgicos respondem a infusões gástricas de diferentes nutrientes e como os estímulos pós-ingestivos afetam a resposta nas regiões dopaminérgicas ventral e dorsal, e das suas projeções axonais no estriado. Deste modo, experiências de microscopia de cálcio de e fotometria de fibra ótica foram executadas em regiões dopaminérgicas – AVT e porção compacta da substância negra (SNc) – e regiões do estriado – NAc e estriado dorsal-lateral (EDL) -, respetivamente, enquanto soluções isocalóricas de gordura e sucrose eram infundidas diretamente no estômago. Adicionalmente, procurou-se ainda perceber a forma como estímulos pós ingestivos afetavam a aprendizagem de reforço no contexto de uma tarefa instrumental. Para isso, uma tarefa probabilística instrumental de duas ações foi desenvolvida de modo a avaliar como estímulos pós-ingestivos modulavam a aprendizagem com base em diferentes probabilidades de obtenção de recompensa que poderiam resultar na administração de soluções de sacarose (calórica) e sucralose (adoçante artificial sem conteúdo calórico) diretamente no estômago e simultaneamente uma recompensa oral sem conteúdo calórico. Experiências de microscopia de cálcio revelaram que a AVT tem uma resposta mais aumentada para injeções intragástricas de sacarose, quando comparadas com injeções intragástrica de óleo de milho ou sucralose. A resposta da SNc não depende do nutriente infundido uma vez que todos os estímulos utilizados resultaram em perfis de atividade dopaminérgica similares. Medição de níveis de dopamina no estriado ventral e dorsal, simultaneamente no mesmo animal, vão de encontro aos resultados previamente reportados que confirmam maior libertação de dopamina no NAc com a administração intragástrica de sacarose. Em oposição, e em conformidade com os resultados obtidos na SNc, o EDL não respondeu a nenhum dos estímulos administrados. Dados preliminares também revelaram que a resposta de neurónios dopaminérgicos da SNc não depende da constituição lipídica da solução administrada, visto que a resposta intragástrica de óleo de milho é semelhante à resposta intragástrica isocalórica de uma solução calórica - SMOF, composto por vários tipos de ácidos gordos. Interessantemente, a resposta do NAc a esta solução lipídica parece mais similar à resposta observada quando da administração intragástrica de sacarose, o que pode significar que a constituição lipídica da solução administrada pode influenciar vias ventrais dopaminérgicas. O desenvolvimento da tarefa probabilística instrumental de duas ações mostrou que os animais, quando dada a opção de escolha, desenvolvem uma preferência clara para a alavanca associada a infusões gástricas de sacarose quando comparada a alavanca associada com infusões gástricas de sucralose. Curiosamente, esta preferência é independente da probabilidade que cada alavanca tem de entregar recompensa. Os resultados deste trabalho permitiram clarificar a hipótese de que a resposta dopaminérgica entre a via mesolímbica (VTA e estriado ventral) e a via nigroestriatal (SNc e estriado dorsal) em resposta a diferentes tipos de estímulos pós-ingestivos é assimétrica. Os resultados do desenvolvimento da tarefa probabilística instrumental de duas ações permitiram inferir parâmetros importantes no contexto de aprendizagem de reforço e decisão baseada em estímulos pós-ingestivos

    Mouth exposure to carbohydrate prior to exercise possibly impairs the efficacy of carbohydrate mouth rinsing during exercise

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    Decker K. P., M. J. Saunders, N. D. Luden, C. J. Womack, and N. J. Hladick. Mouth Exposure to Carbohydrate Prior to Exercise Possibly Impairs the Efficacy of Carbohydrate Mouth Rinsing during Exercise. Purpose: Carbohydrate mouth-rinsing (CHO-MR) during intense endurance exercise has been associated with improved cycling performance, due to neurological influences. However, prior studies have reported the efficacy of CHO-MR is attenuated following a pre-exercise meal. To determine if this outcome is related to desensitization of CHO receptors (rather than metabolic effects following digestion), this study will investigate whether CHO-MR prior to exercise influences cycling performance when CHO-MR is also used during exercise. Methods: Eight trained cyclists (age, 24 ± 6 yr; height, 176 ± 6 cm; weight 75 ± 12 kg; VO2max, 61 ± 8 ml/kg/min) completed three exercise trials, each consisting of 15-min of incremental, constant-load exercise followed by a simulated 30-km time-trial (TT). Treatment beverages in the trials were randomly counterbalanced: a) PL_PL: placebo before and during exercise, b) PL_CHO: placebo pre-exercise, CHO-MR during exercise, and c) R_CHO: CHO-MR before and during exercise. Physiological responses (VO2, VE, RER, RPE, heart rate, blood glucose and lactate) were assessed during constant-load exercise and during the TT. Magnitude-based qualitative inferences were used to evaluate differences in responses between treatments. Results: TT performance was ‘possibly’ impaired (59% likelihood) with R_CHO (57.3 ± 3.6) versus PL_CHO (56.9 ± 3.0 min). Both trials were ‘likely’ slower than PL_PL (55.8 ± 3.1 min), but the reliability of performance data from this trial may have been impacted by measurement error, which limited our ability to determine the influence of CHO-MR during exercise. Physiological responses between treatments during constant-load cycling, and the TT were generally similar between all treatments. Conclusion: A pre-exercise CHO-MR had a possibly negative impact on cycling performance that also included CHO-MR during exercise. Although further evidence is required to validate this finding, our data suggests that desensitization of CHO receptors related to recent CHO exposure may be partially responsible for previous reports that the efficacy of CHO-MR during exercise are attenuated by pre-exercise feedings. Keywords: CYCLING, CARBOHYDRATE, MOUTH-RINSING, PERFORMANCE, ERGOGENIC-AIDS
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