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1.
The "sweet" effect: Comparative assessments of dietary sugars on cognitive performance.
Ginieis, R, Franz, EA, Oey, I, Peng, M
Physiology & behavior. 2018;:242-247
Abstract
In recent years there has been increasing interest in studying cognitive effects associated with sugar consumption. Neuro-cognitive research has confirmed that glucose, as a main energy substrate for the brain, can momentarily benefit cognitive performances, particularly for memory functioning. However, there is still limited understanding of relative effects of other common sugars (e.g., fructose and sucrose) on cognitive performance. The present study tested in 49 people the effects of three common dietary sugars against a placebo sweetener (i.e., sucralose), on performance of three well-studied cognitive tasks - simple response time, arithmetic, and Stroop interference, all of which are suggested to rely on the prefrontal lobe. A double-blind, placebo-controlled, cross-over experimental design was used. Results revealed that ingestion of glucose and sucrose led to poorer performances on the assessed tasks as opposed to fructose and the placebo (p<0.05); these effects were particularly pronounced under the fasting condition in comparison to the non-fasting condition (p<0.001). Overall, these results indicate that cognitive effects of sugar are unlikely to be mediated by the perception of sweetness. Rather, the effects are mediated by glucose. Further research should systematically assess effects of dietary sugars on other cognitive domains, such as memory, to give further insights on general cognitive effects of sugar consumption.
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Evolution of complex, discreet nutrient sensing pathways.
Mehat, K, Corpe, CP
Current opinion in clinical nutrition and metabolic care. 2018;(4):289-293
Abstract
PURPOSE OF REVIEW The current review summarizes and discusses current research on differences elicited between sugars and nonnutritive sweeteners via sugar-sensing pathways. RECENT FINDINGS Sugars, sweeteners, and sweetening agents are all perceived as sweet tasting because of their ability to bind to the type 1 taste receptor family of sweet taste receptors in the oral cavity. The ability of a wide variety of chemical ligands to activate the sweet taste receptor highlights the importance of sweet-tasting foods during human evolution. The sweet taste receptor has been located in the gut, and differences between oral and gut sugar-sensing pathways are discussed. SUMMARY Differences in the sweetness transduction cascade, and neuronal signalling may result in incretin hormone release upon activation of the sweet taste receptor from some sweeteners, but not others.
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3.
Age-Related Deficits in Taste and Smell.
Doty, RL
Otolaryngologic clinics of North America. 2018;(4):815-825
Abstract
Disturbances in both the ability to smell and to taste are common in older persons. Such disturbances influence nutrition, safety, quality of life, and psychological and physical health. The anatomic and physiologic causes of age-related disturbances are multiple and interacting, and depend on genetic and environmental factors. Frank losses of function, distortions, and hallucinations are common. Most distortions resolve over time, although this can take months or even years. Olfactory dysfunction occurs during the earliest stages of several neurologic disorders, most notably Alzheimer's disease and Parkinson's disease, likely heralding the onset of the underlying pathologies.
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Prolonged Exposure to Monosodium Glutamate in Healthy Young Adults Decreases Perceived Umami Taste and Diminishes Appetite for Savory Foods.
Noel, CA, Finlayson, G, Dando, R
The Journal of nutrition. 2018;(6):980-988
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Abstract
BACKGROUND Research suggests that increased consumption of sweet, salt, or fat is associated with diminished perceived taste intensity and shifted preferences for the respective stimulus. It is unknown whether a similar effect occurs with the consumption of umami. OBJECTIVE The aim of the study was to investigate the influence of habitual exposure to umami stimuli on umami taste perception, hedonics, and satiety. METHODS Fifty-eight healthy men (n = 16) and women (n = 42) participated in a parallel-group, randomized controlled study. The normal-weight [mean ± SD body mass index (kg/m2): 21.8 ± 2.2] group of young adults (mean ± SD age: 22.7 ± 6.2 y) consumed vegetable broth daily for 4 wk. The broth for the treatment group (n = 28) was supplemented with 3.8 g monosodium glutamate (MSG), whereas the control group (n = 30) consumed a sodium-matched broth without MSG. Perceived umami taste intensity and discrimination in MSG solutions; liking, wanting, and preference of a variety of umami-rich foods; satiation and satiety from an ad libitum meal; and anthropometric measures were evaluated at baseline and at week 4. General linear models assessed the effect of treatment on change from baseline for all outcomes and tested for effect modification of sex. RESULTS Relative to controls, increased consumption of MSG for 4 wk diminished umami taste in women (8.4 units on generalized Labeled Magnitude Scale; 95% CI: -13.8, -3.1 units; P = 0.013). The desire for and intake of savory foods decreased after MSG treatment in both sexes with an ad libitum meal (desire: -7.7 units; 95% CI: -13.7, -1.7 units; P = 0.04; intake: -36 g; 95% CI: -91, 19 g; P = 0.04). CONCLUSION Our results highlight that a month-long diet high in umami stimuli attenuates perceived umami taste and appetite for savory foods in a young, healthy population. Our findings contribute to the understanding of food choice, a factor in the development and maintenance of obesity, as well as the etiology of protein-related health conditions such as osteoporosis and kidney disease. This study is registered at www.clinicaltrials.gov as NCT03010930.
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The evolution of taste and perinatal programming of taste preferences.
Podzimek, Š, Dušková, M, Broukal, Z, Rácz, B, Stárka, L, Dušková, J
Physiological research. 2018;(Suppl 3):S421-S429
Abstract
Taste is important for food intake. The fetus first experiences taste through amniotic fluid, and later via mother's milk. Early human experience with taste has a key importance for later acceptance of food. Dietary behavior is determined by the interaction of many different factors. The development of the olfactory and taste receptors begins at 7-8 weeks of gestation. An early sensitive period probably exists when flavor preference is established. Sweet taste is preferred in early childhood; this is the reason why children are at increased risk of over-consuming saccharides. Gustatory sensitivity declines with age. The threshold for the perception of each basic taste differs, and is established genetically. In this review, we summarize published data on taste preferences and its development and changes during life.
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Expression of the candidate fat taste receptors in human fungiform papillae and the association with fat taste function.
Liu, D, Costanzo, A, Evans, MDM, Archer, NS, Nowson, C, Duesing, K, Keast, R
The British journal of nutrition. 2018;(1):64-73
Abstract
Significant experimental evidence supports fat as a taste modality; however, the associated peripheral mechanisms are not well established. Several candidate taste receptors have been identified, but their expression pattern and potential functions in human fungiform papillae remain unknown. The aim of this study is to identify the fat taste candidate receptors and ion channels that were expressed in human fungiform taste buds and their association with oral sensory of fatty acids. For the expression analysis, quantitative RT-PCR (qRT-PCR) from RNA extracted from human fungiform papillae samples was used to determine the expression of candidate fatty acid receptors and ion channels. Western blotting analysis was used to confirm the presence of the proteins in fungiform papillae. Immunohistochemistry analysis was used to localise the expressed receptors or ion channels in the taste buds of fungiform papillae. The correlation study was analysed between the expression level of the expressed fat taste receptors or ion channels indicated by qRT-PCR and fat taste threshold, liking of fatty food and fat intake. As a result, qRT-PCR and western blotting indicated that mRNA and protein of CD36, FFAR4, FFAR2, GPR84 and delayed rectifying K+ channels are expressed in human fungiform taste buds. The expression level of CD36 was associated with the liking difference score (R -0·567, β=-0·04, P=0·04) between high-fat and low-fat food and FFAR2 was associated with total fat intake (ρ=-0·535, β=-0·01, P=0·003) and saturated fat intake (ρ=-0·641, β=-0·02, P=0·008).
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Impact of sugar on the body, brain, and behavior.
Freeman, CR, Zehra, A, Ramirez, V, Wiers, CE, Volkow, ND, Wang, GJ
Frontiers in bioscience (Landmark edition). 2018;(12):2255-2266
Abstract
Sugar is highly palatable and rewarding, both in its taste and nutritive input. Excessive sugar consumption, however, may trigger neuroadaptations in the reward system that decouple eating behavior from caloric needs and leads to compulsive overeating. Excessive sugar intake is in turn associated with adverse health conditions, including obesity, metabolic syndrome, and inflammatory diseases. This review aims to use recent evidence to connect sugar's impact on the body, brain, and behavior to elucidate how and why sugar consumption has been implicated in addictive behaviors and poor health outcomes.
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A workshop on 'Dietary Sweetness-Is It an Issue?'.
Wittekind, A, Higgins, K, McGale, L, Schwartz, C, Stamataki, NS, Beauchamp, GK, Bonnema, A, Dussort, P, Gibson, S, de Graaf, C, et al
International journal of obesity (2005). 2018;(4):934-938
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Abstract
This report summarises a workshop convened by ILSI Europe on 3 and 4 April 2017 to discuss the issue of dietary sweetness. The objectives were to understand the roles of sweetness in the diet, establish whether exposure to sweetness affects diet quality and energy intake, and consider whether sweetness per se affects health. Although there may be evidence for tracking of intake of some sweet components of the diet through childhood, evidence for tracking of whole diet sweetness, or through other stages of maturity are lacking. The evidence to date does not support adverse effects of sweetness on diet quality or energy intake, except where sweet food choices increase intake of free sugars. There is some evidence for improvements in diet quality and reduced energy intake where sweetness without calories replaces sweetness with calories. There is a need to understand the physiological and metabolic relevance of sweet taste receptors on the tongue, in the gut and elsewhere in the body, as well as possible differentiation in the effects of sustained consumption of individual sweeteners. Despite a plethora of studies, there is no consistent evidence for an association of sweetness sensitivity/preference with obesity or type 2 diabetes. A multifaceted integrated approach, characterising nutritive and sensory aspects of the whole diet or dietary patterns, may be more valuable in providing contextual insight. The outcomes of the workshop could be used as a scientific basis to inform the expert community and create more useful dialogue among health care professionals.
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Frontostriatal and behavioral adaptations to daily sugar-sweetened beverage intake: a randomized controlled trial.
Burger, KS
The American journal of clinical nutrition. 2017;(3):555-563
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Abstract
Background: Current obesity theories suggest that the repeated intake of highly palatable high-sugar foods causes adaptions in the striatum, parietal lobe, and prefrontal and visual cortices in the brain that may serve to perpetuate consumption in a feed-forward manner. However, the data for humans are cross-sectional and observational, leaving little ability to determine the temporal precedence of repeated consumption on brain response.Objective: We tested the impact of regular sugar-sweetened beverage intake on brain and behavioral responses to beverage stimuli.Design: We performed an experiment with 20 healthy-weight individuals who were randomly assigned to consume 1 of 2 sugar-sweetened beverages daily for 21 d, underwent 2 functional MRI sessions, and completed behavioral and explicit hedonic assessments.Results: Consistent with preclinical experiments, daily beverage consumption resulted in decreases in dorsal striatal response during receipt of the consumed beverage (r = -0.46) and decreased ventromedial prefrontal response during logo-elicited anticipation (r = -0.44). This decrease in the prefrontal response correlated with increases in behavioral disinhibition toward the logo of the consumed beverage (r = 0.54; P = 0.02). Daily beverage consumption also increased precuneus response to both juice logos compared with a tasteless control (r = 0.45), suggesting a more generalized effect toward beverage cues. Last, the repeated consumption of 1 beverage resulted in an explicit hedonic devaluation of a similar nonconsumed beverage (P < 0.001).Conclusions: Analogous to previous reports, these initial results provide convergent data for a role of regular sugar-sweetened beverage intake in altering neurobehavioral responses to the regularly consumed beverage that may also extend to other beverage stimuli. Future research is required to provide evidence of replication in a larger sample and to establish whether the neurobehavioral adaptations observed herein are specific to high-sugar and/or nonnutritive-sweetened beverages or more generally related to the repeated consumption of any type of food. This trial was registered at clinicaltrials.gov as NCT02624206.
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Flavor Perception and Preference Development in Human Infants.
Forestell, CA
Annals of nutrition & metabolism. 2017;:17-25
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Abstract
As most parents and caregivers are aware, feeding children a nutritionally balanced diet can be challenging. Children are born with a biological predisposition to prefer sweet and to avoid bitter foods such as green leafy vegetables. It has been hypothesized that this predisposition evolved to attract children to energy-dense foods while discouraging the consumption of toxins. Although this may have enhanced survival in environments historically characterized by food scarcity, it is clearly maladaptive in many of today's food environments where children are surrounded by an abundance of sweet-tasting, unhealthful foods and beverages that place them at risk for excessive weight gain. Because overweight or obese children tend to become overweight or obese adults who are at risk for a range of cardiovascular diseases, it is of primary importance to develop effective evidence-based strategies to promote the development of healthy eating styles. Fortunately, accumulating evidence suggests that, starting before birth and continuing throughout development, there are repeated and varied opportunities for children to learn to enjoy the flavors of healthful foods. Because flavors are transmitted from the maternal diet to amniotic fluid and breast milk, mothers who consume a variety of healthful foods throughout pregnancy and lactation provide their infants with an opportunity to learn to like these flavors. This in turn eases the transition to healthful foods at weaning. In contrast, infants fed formula learn to prefer its invariant flavor profile, which differs from breast milk, and may initially be less accepting of flavors not found in formula. This process can continue throughout weaning and into childhood if infants are repeatedly exposed to a variety of healthful foods, even if they initially dislike them. These early-life sensory experiences establish food preferences and dietary patterns that set the stage for lifelong dietary habits.