Alter Food Preference Research Articles

The association of smoking with different eating and dietary behaviours: A cross-sectional analysis of 80 296 United Kingdom adults.

Smokers typically have a lower body mass index (BMI) than non-smokers, while smoking cessation is associated with weight gain. In pre-clinical research, nicotine in tobacco smoking suppresses appetite and influences subsequent eating behaviour; however, this relationship is unclear in humans. This study measured the associations of smoking with different eating and dietary behaviours. A cross-sectional analysis of data from health assessments conducted between 2004 and 2022. An independent healthcare-based charity within the United Kingdom. A total of 80 296 men and women (mean ± standard deviation [SD]: age, 43.0 ± 10.4years; BMI, 25.7 ± 4.2kg/m2; 62.5% male) stratified into two groups based on their status as a smoker (n = 6042; 7.5%) or non-smoker (n = 74 254; 92.5%). Smoking status (self-report) was the main exposure, while the primary outcomes were selected eating and dietary behaviours. Age, sex and socioeconomic status (index of multiple deprivation [IMD]) were included as covariates and interaction terms, while moderate-to-vigorous exercise and sleep quality were included as covariates only. Smokers had lower odds of snacking between meals and eating food as a reward or out of boredom versus non-smokers (all odds ratio [OR] ≤ 0.82; P < 0.001). Furthermore, smokers had higher odds of skipping meals, going more than 3h without food, adding salt and sugar to their food, overeating and finding it hard to leave something on their plate versus non-smokers (all OR ≥ 1.06; P ≤ 0.030). Additionally, compared with non-smokers, smoking was associated with eating fried food more times per week (rate ratio [RR] = 1.08; P < 0.001), eating fewer meals per day, eating sweet foods between meals and eating dessert on fewer days per week (all RR ≤ 0.93; P < 0.001). Several of these relationships were modified by age, sex and IMD. Smoking appears to be associated with eating and dietary behaviours consistent with inhibited food intake, low diet quality and altered food preference. Several of these relationships are moderated by age, sex and socioeconomic status.

Chemosensory changes during chemotherapy.

Chemosensory changes that occur during chemotherapy can significantly impact food enjoyment, quality of life and recovery. To investigate chemosensory changes reported by oncology patients during chemotherapy. A mixed-method cross-sectional study design was used to explore 100 cancer patients' experiences of chemosensory changes during chemotherapy. All patients completed a questionnaire assessing their taste and smell preferences. A purposive sample of 30 patients underwent a semi-structured interview to elicit their thoughts on their experienced chemosensory changes. Descriptive statistics and themes were examined. The mean age of the sample was 50.56 years, and the majority of participants were female. The most stated taste alteration was bitter, while altered food preferences were also commonly experienced. Furthermore, most patients experienced unpleasant odours around food, while some experienced these odours even when food was not present. Overall, five themes were identified: changes in taste, changes in smell, changes in social life, altered comfort and food preferences. Chemosensory changes related to cancer and its treatment impact a person's nutrient intake, food-related behaviours, quality of life and treatment response. Patients who experience chemotherapy-associated chemosensory changes require specialised nutritional therapy to increase their eating-related pleasure. As part of the nutritional assessment, chemosensory alterations should be evaluated regularly.

Nourishing Earth, Nourishing Ourselves. Part 1: Linking Plant Diversity With the Health of Livestock and Humans

The foods we eat reveal the nature of our relationships with the places where we live. In this first of 3 papers, I highlight how the “taste of a place,” or terroir, enables animals to meet their needs for nutrients and self-medicate by learning to eat nourishing combinations of foods in utero and early in life and by metabolically mediated flavor-feedback associations that alter food preferences as needs arise. When domestic herbivores learn to forage in landscapes with diverse mixtures of plant species, phytochemically rich diets bolster their health and protect them from diseases through anti-microbial, antiparasitic, anti-inflammatory, and immune-boosting properties. Human benefits accrue as livestock assimilate some phytochemicals and convert others into metabolites that enhance the flavors of meat and dairy and promote human health. During the past century, to our detriment, the flavors of meat, dairy, and produce became bland, while ultra-processed foods became irresistible as farmers and ranchers emphasized yield and transportability over taste and phytochemical and biochemical richness. At the same time, the food industry learned how to produce ultra-processed “foods” that hijack preferences. They do so by linking artificial flavors with metabolically mediated feedback from cells and organs in response to refined carbohydrates and sugars that, together with artificial flavors, obscure nutritional uniformity and undermine health. Fossil fuel-based food production has come at great costs ecologically, economically, and socially. With the uncertain availability and prices of fossil fuels a concern and the transition to clean energy a necessity, we have an opportunity to grow nutrient-rich foods in ways that nurture our relationship with life on Earth. Veterinarians can help people realize fossil fuels and climate change are part of an interwoven complex of food- and environment-related sustainability challenges that affect health and welfare. As voices for One Health, we must all come to value the role of plant diversity in creating homes, grocery stores, and pharmacies for all life below and above ground, while fixing carbon and reducing methane, thus helping to abate warming climates.

Isolated Insular Stroke: An Interesting Report of Two Cases.

Isolated Insular Stroke: An Interesting Report of Two Cases.

Meal Patterns and Food Choices of Female Rats Fed a Cafeteria-Style Diet Are Altered by Gastric Bypass Surgery.

After Roux-en-Y gastric bypass surgery (RYGB), rats tend to reduce consumption of high-sugar and/or high-fat foods over time. Here, we sought to investigate the behavioral mechanisms underlying these intake outcomes. Adult female rats were provided a cafeteria diet comprised of five palatable foodstuffs varying in sugar and fat content and intake was monitored continuously. Rats were then assigned to either RYGB, or one of two control (CTL) groups: sham surgery or a nonsurgical control group receiving the same prophylactic iron treatments as RYGB rats. Post-sur-gically, all rats consumed a large first meal of the cafeteria diet. After the first meal, RYGB rats reduced intake primarily by decreasing the meal sizes relative to CTL rats, ate meals more slowly, and displayed altered nycthemeral timing of intake yielding more daytime meals and fewer nighttime meals. Collectively, these meal patterns indicate that despite being motivated to consume a cafeteria diet after RYGB, rats rapidly learn to modify eating behaviors to consume foods more slowly across the entire day. RYGB rats also altered food preferences, but more slowly than the changes in meal patterns, and ate proportionally more energy from complex carbohydrates and protein and proportionally less fat. Overall, the pattern of results suggests that after RYGB rats quickly learn to adjust their size, eating rate, and distribution of meals without altering meal number and to shift their macronutrient intake away from fat; these changes appear to be more related to postingestive events than to a fundamental decline in the palatability of food choices.

Gut peptide regulation of food intake - evidence for the modulation of hedonic feeding.

The number of people living with obesity has tripled worldwide since 1975 with serious implications for public health, as obesity is linked to a significantly higher chance of early death from associated comorbidities (metabolic syndrome, type 2 diabetes, cardiovascular disease and cancer). As obesity is a consequence of food intake exceeding the demands of energy expenditure, efforts are being made to better understand the homeostatic and hedonic mechanisms governing food intake. Gastrointestinal peptides are secreted from enteroendocrine cells in response to nutrient and energy intake, and modulate food intake either via afferent nerves, including the vagus nerve, or directly within the central nervous system, predominantly gaining access at circumventricular organs. Enteroendocrine hormones modulate homeostatic control centres at hypothalamic nuclei and the dorso-vagal complex. Additional roles of these peptides in modulating hedonic food intake and/or preference via the neural systems of reward are starting to be elucidated, with both peripheral and central peptide sources potentially contributing to central receptor activation. Pharmacological interventions and gastric bypass surgery for the treatment of type 2 diabetes and obesity elevate enteroendocrine hormone levels and also alter food preference. Hence, understanding of the hedonic mechanisms mediated by gut peptide action could advance development of potential therapeutic strategies for the treatment of obesity and its comorbidities.

High-fat Feeding Causes Inflammation and Insulin Resistance in the Ventral Tegmental Area in Mice

The reward system plays an important role in the pathogenesis of not only drug addiction, but also diet-induced obesity. Recent studies have shown that insulin and leptin receptor signaling in the ventral tegmental area (VTA) regulate energy homeostasis and that their dysregulation is responsible for obesity and altered food preferences. Although a high-fat diet (HFD) induces inflammation that leads to insulin and leptin resistance in the brain, it remains unclear whether HFD induces inflammation in the VTA. In the present study, we placed male mice on a chow diet or HFD for 3, 7, and 28 days and evaluated the mRNA expression of inflammatory cytokines and microglial activation markers in the VTA. The HFD group showed significantly elevated mRNA expressions of IL1β at 3 days; tumor necrosis factor-alpha (TNFα), IL1β, IL6, Iba1, and CD11b at 7 days; and TNFα, IL1β, Iba1, and CD11b at 28 days. The changes in TNFα were also confirmed in immunohistochemical analysis. Next, after administration of chow or HFD for 7 days, we selected mice with equal weights in both groups. In experiments using these mice, Akt phosphorylation in the VTA was significantly decreased after intracerebroventricular injection of insulin, whereas no change in STAT3 phosphorylation was found with leptin. Taken together, these results suggest that HFD induces inflammation at least partly associated with microglial activation in the VTA leading to insulin resistance, independently of the energy balance. Our data provide new insight into the pathophysiology of obesity caused by a dysfunctional reward system under HFD conditions.

Dose Frequency Optimization of the Dual Amylin and Calcitonin Receptor Agonist KBP-088: Long-Lasting Improvement in Food Preference and Body Weight Loss.

Dual amylin and calcitonin receptor agonists (DACRAs) are novel candidates for treatment of type 2 diabetes and obesity because of their beneficial effects on body weight, blood glucose, insulin sensitivity, and food preference, at least short-term. DACRAs activate the receptors for a prolonged time period, resulting in metabolic effects superior to those of amylin. Because of the prolonged receptor activation, different dosing intervals and, hence, less frequent receptor activation might change the efficacy of DACRA treatment in terms of weight loss and food preference. In this study, we compared daily dosing to dosing every other day with the aim of understanding the optimal balance between efficacy and tolerability. Obese and lean male Sprague-Dawley rats were treated with the DACRA KBP-088, applying two different dosing intervals (1.5 nmol/kg once daily and 3 nmol/kg every other day) to assess the effect on body weight, food intake, glucose tolerance, and food preference when given the choice between chow (13% fat) and a high-fat diet (60% fat). Treatment with KBP-088 induced significant weight loss, reduction in adiposity, improvement in glucose control, and altered food preference toward food that is less calorie-dense. KBP-088 dosed every other day (3 nmol/kg) was superior to KBP-088 once daily (1.5 nmol/kg) in terms of weight loss and improvement of food preference. The beneficial effects were evident in both lean and obese rats. Hence, dosing KBP-088 every other day positively affects overall efficacy on metabolic parameters regardless of the lean/obese state, suggesting that less-frequent dosing with KBP-088 could be feasible. SIGNIFICANCE STATEMENT: Here, we show that food preference can be altered chronically toward choices that are less calorie-dense by pharmacological treatment. Further, pharmacological dosing regimens affect the efficacy differently, as dosing every other day improved body weight loss and alterations in food preference compared with daily dosing. This suggest that alterations of the dosing regimens could be feasible in the treatment of obesity.

Neurosecretory protein GL induces fat accumulation in mice.

We recently discovered a novel gene encoding a small secretory protein, neurosecretory protein GL (NPGL), which stimulates feeding behavior in mice following acute administration. These findings suggest that dysregulation of NPGL contributes to obesity and metabolic disease. To explore this possibility, we investigated the impact of prolonged exposure to NPGL through 13 days of chronic intracerebroventricular (i.c.v.) infusion and examined feeding behavior, body composition, expressions of lipid metabolic factors, respiratory metabolism, locomotor activity, and food preference. Under standard chow diet, NPGL increased white adipose tissue (WAT) mass without affecting feeding behavior and body mass. In contrast, when fed a high-calorie diet, NPGL stimulated feeding behavior and increased body mass concomitant with marked fat accumulation. Quantitative reverse transcription polymerase chain reaction (RT-PCR) analysis revealed that mRNA expressions for key enzymes and related factors involved in lipid metabolism were increased in WAT and liver. Likewise, analyses of respiratory metabolism and locomotor activity revealed that energy expenditure and locomotor activity were significantly decreased by NPGL. In contrast, selective feeding of macronutrients did not alter food preference in response to NPGL, although total calorie intake was increased. Immunohistochemical analysis revealed that NPGL-containing cells produce galanin, a neuropeptide that stimulates food intake. Taken together, these results provide further support for NPGL as a novel regulator of fat deposition through changes in energy intake and locomotor activity.

Change of Lipid Peroxidation System – Antioxidant Protection Parameters in Adolescents with Obesity and Fatty Hepatosis

Background. Spread of childhood obesity is associated with social and economic factors of modern lifestyle that alter food preferences and lead to sedentary life. Nowadays fatty hepatosis is considered a hepatic manifestation of the metabolic syndrome, which is linked to the rising prevalence of obesity among the population. There is evidence of a correlation between metabolic disorders and oxidative stress reactions.Aims. To study characteristics of lipid peroxidation system and antioxidant defense processes in adolescents with fatty hepatosis.Materials and methods. We examined 15 adolescents with obesity and fatty hepatosis, 20 adolescents with obesity and without fatty hepatosis, and 20 apparently healthy adolescents, who formed the control group. Spectrophotometric and fluorometric methods were used in the research.Results. We found that some components of antioxidant status of adolescents with obesity and fatty hepatosis were decreased, both in comparison with the group with obesity without hepatosis and control group.Conclusions. It is recommended that patients with obesity and fatty hepatosis take antioxidants in addition to metabolic therapy.

Being born small-for-gestational-age is associated with an unfavourable dietary intake in Danish adolescent girls: findings from the Danish National Birth Cohort.

Individuals born small have an increased risk for developing type 2 diabetes. Altered food preferences in these subjects seem to play a role; however, limited evidence is available on the association between being born small-for-gestational-age (SGA) at term and food intake in adolescence. Alterations in leptin, ghrelin and dopamine levels are suggested mechanisms linking SGA with later food intake. From a large prospective Danish National Birth Cohort, we compared dietary intake of adolescents being born SGA with normal-for-gestational-age (NGA) adolescents. Intake of foods and nutrients was assessed by a validated food frequency questionnaire in a subsample of 15,607 14-year-old individuals born at term. SGA was defined by birth weight (BW) &lt;10th percentile (n = 1470) and NGA as BW between 10 and 90th percentile (n = 14,137) according to sex and gestational age-specific BW standard curves. Girls born SGA had a 7% (95% CI: 3-12%, P = 0.002) higher intake of added sugar and a 2-8% lower intake of dietary fibre, vegetables, polyunsaturated fatty acids, and total n-6, compared with NGA girls (P &lt; 0.05). Adjusting for parental socio-occupational status, maternal smoking and diet in pregnancy did not substantially change the differences in dietary intake, except from dietary fibre, which were no longer statistically significant. No significant differences in dietary intake between SGA and NGA boys were found. In summary, girls born SGA had an unfavourable dietary intake compared with NGA girls. These differences persisted after controlling for potential confounders, thus supporting a fetal programming effect on dietary intake in girls born SGA at term. However, residual confounding by other factors operating early in childhood cannot be excluded.

Rapid descriptive product profile techniques for food product development for cancer survivors

The food industry has neglected food product development for cancer survivors, individuals who commonly experience taste and smell changes, have altered food preferences and a changed relationship with food. The aim of this literature review is to identify novel sensory science methods for rapid descriptive product profiling to guide food product development for cancer survivors. Uncomplicated techniques such as CATA with hedonic ratings are shown to generate valid and reliable product descriptions among children and older and low income adults. Application of consumer descriptive methods such as CATA, to incorporate unique sensory and extrinsic product perceptions in the new product development process, could result in nutritionally-fortified food products with appealing sensory qualities for cancer survivors.

Appetite Suppression and Altered Food Preferences Coincide with Changes in Appetite-Mediating Hormones During Energy Deficit at High Altitude, But Are Not Affected by Protein Intake.

Karl, J. Philip, Renee E. Cole, Claire E. Berryman, Graham Finlayson, Patrick N. Radcliffe, Matthew T. Kominsky, Nancy E. Murphy, John W. Carbone, Jennifer C. Rood, Andrew J. Young, and Stefan M. Pasiakos. Appetite suppression and altered food preferences coincide with changes in appetite-mediating hormones during energy deficit at high altitude, but are not affected by protein intake. High Alt Med Biol. 19:156–169, 2018.—Anorexia and unintentional body weight loss are common during high altitude (HA) sojourn, but underlying mechanisms are not fully characterized, and the impact of dietary macronutrient composition on appetite regulation at HA is unknown. This study aimed to determine the effects of a hypocaloric higher protein diet on perceived appetite and food preferences during HA sojourn and to examine longitudinal changes in perceived appetite, appetite mediating hormones, and food preferences during acclimatization and weight loss at HA. Following a 21-day level (SL) period, 17 unacclimatized males ascended to and resided at HA (4300 m) for 22 days. At HA, participants were randomized to consume measured standard-protein (1.0 g protein/kg/d) or higher protein (2.0 g/kg/d) hypocaloric diets (45% carbohydrate, 30% energy restriction) and engaged in prescribed physical activity to induce an estimated 40% energy deficit. Appetite, food preferences, and appetite-mediating hormones were measured at SL and at the beginning and end of HA. Diet composition had no effect on any outcome. Relative to SL, appetite was lower during acute HA (days 0 and 1), but not different after acclimatization and weight loss (HA day 18), and food preferences indicated an increased preference for sweet- and low-protein foods during acute HA, but for high-fat foods after acclimatization and weight loss. Insulin, leptin, and cholecystokinin concentrations were elevated during acute HA, but not after acclimatization and weight loss, whereas acylated ghrelin concentrations were suppressed throughout HA. Findings suggest that appetite suppression and altered food preferences coincide with changes in appetite-mediating hormones during energy deficit at HA. Although dietary protein intake did not impact appetite, the possible incongruence with food preferences at HA warrants consideration when developing nutritional strategies for HA sojourn.

Low birth weight is associated with increased fat intake in school-aged boys.

Evidence suggests that both high and low birth weight children have increased the risk for obesity and the metabolic syndrome in adulthood. Previously we have found altered feeding behaviour and food preferences in pre-school children and adults born with low birth weight. In this study, we investigated if birth weight was associated with different intake of fat, carbohydrate and/or protein at 6-12 years of age. This is a cross-sectional study where 255 guardians answered online and telephone questions including anthropometrics and demographic data, parental family food rules (food control, encouragement and restriction) and a complete web-based FFQ for their children (130 boys and 125 girls). Baseline demographic and parental food rules characteristics did not differ accordingly to sex. Linear regression models were conducted separately for each sex, adjusted for income, age and maternal age. There were no differences in total energy intake, but energy density (ED, energy content/g) was negatively associated with birth weight in boys. Macronutrient analysis showed that ED intake was from a greater intake of fat. Birth weight was not a significant predictor of protein and carbohydrate intake in boys. In girls, we saw a positive correlation between fat intake and cholesterol intake v. birth weight, but no association with ED intake (results did not remain after adjustment). The study shows that low birth weight is associated with altered fat intake in childhood in a sex-specific manner. It is likely that biological factors such as fetal programming of homoeostatic and/or hedonic pathways influencing food preferences are involved in this process.

Hippocampus ghrelin receptor signaling promotes socially-mediated learned food preference

Social cues are potent regulators of feeding behavior, yet the neurobiological mechanisms through which social cues influence food intake are poorly understood. Here we investigate the hypothesis that the appetite-promoting gut-derived hormone, ghrelin, signals in the hippocampus to promote learned social aspects of feeding behavior. We utilized a procedure known as 'social transmission of food preference' (STFP) in which rats ('Observers') experience a social interaction with another rat ('Demonstrators') that recently consumed flavored/scented chow. STFP learning in Observer rats is indicated by a significant preference for the Demonstrator paired flavor of chow vs. a novel unpaired flavor of chow in a subsequent consumption choice test. Our results show that relative to vehicle treatment, ghrelin targeted to the ventral CA1 subregion of the hippocampus (vHP) enhanced STFP learning in rats. Additionally, STFP was impaired following peripheral injections of l-cysteine that reduce circulating ghrelin levels, suggesting that vHP ghrelin-mediated effects on STFP require peripheral ghrelin release. Finally, the endogenous relevance of vHP ghrelin receptor (GHSR-1A) signaling in STFP is supported by our data showing that STFP learning was eliminated following targeted viral vector RNA interference-mediated knockdown of vHP GHSR-1A mRNA. Control experiments indicate that vHP ghrelin-mediated STFP effects are not secondary to altered social exploration and food intake, nor to altered food preference learning based on nonsocial olfactory cues. Overall these data reveal a novel neurobiological system that promotes conditioned, social aspects of feeding behavior.

Assessing olfactory functions in patients with Barth syndrome.

Barth syndrome is a rare X-linked disease affecting less than 200 individuals worldwide. Several comorbidities have been associated with the pathology and, among those, cardiac myopathy and neutropenia are the most life threatening. The appropriate nutritive support is important to sustain the everyday life of Barth syndrome patients given the chronic fatigue they experience. Since they often prefer salty and fried food, and avoid vegetables and fruits, their eating habit and food preferences do not always provide the proper amount of vitamins and amino acids. It has been indeed reported that Barth syndrome patients have altered taste sensitivity. As olfaction also contributes to food consumption and flavor perception, we decided to investigate their olfactory abilities using the “Sniffin’ sticks’ extended test”. We found no significant difference in any of the tested olfactory abilities between the group of Barth syndrome patients and the healthy controls. In summary, altered food preference of Barth boys could not be easily explained with an altered olfactory perception.

Altered food preferences and chemosensory perception during chemotherapy in breast cancer patients: A longitudinal comparison with healthy controls

Changes in food preferences and chemosensory function are frequently reported during chemotherapy, but the nature of these changes are largely unknown. We followed and characterized food preferences, taste and smell function over chemotherapy treatment in breast cancer patients and compared to women without cancer. Furthermore, we assessed associations between taste and smell function and food preferences in breast cancer patients.Women with newly diagnosed breast cancer (n=28) completed test sessions before, halfway, shortly after, and six months after chemotherapy. Twenty-eight women without cancer were tested at similar time points as control. During test sessions, food preferences were assessed with the Macronutrient and Taste Preference Ranking Task. Self-reported taste and smell function were tested on a visual analogue scale. Objective taste and smell function were assessed with Taste Strips and Sniffin’ Sticks.Breast cancer patients liked high-protein, high-fat, sweet, and savoury products less during chemotherapy, which returned to baseline six months after chemotherapy, while the control group was stable over time. Chemotherapy led to a decreased taste and smell function which recovered six months after chemotherapy. A better self-reported taste was associated with higher liking of high-protein, low-energy, savoury and sweet products.Breast cancer patients undergoing chemotherapy have altered food preferences for certain macronutrients, but not specifically for sweet or savoury tastes. Chemotherapy has a transient influence on food preferences and chemosensory function, of which patients should be informed prior to treatment, and which should be monitored during treatment due to the consequences for nutritional intake and quality of life.

Determinants of self-regulation in obesity: formation of implicit food preferences

&lt;b&gt;Background&lt;/b&gt;&lt;br /&gt; The objective of this study was to investigate whether motor behavior can impact self-regulation of food intake in individuals with obesity. We utilized purposeful movement of the hand as a means to influence tendencies to approach and avoid foods compatible and incompatible with the weight loss goals. &lt;br /&gt; &lt;br /&gt; &lt;b&gt;Participants and procedure&lt;/b&gt;&lt;br /&gt; One hundred individuals with obesity (BMI ≥ 30) participated in this study. The participants were randomized into 2 experimental groups. The first experimental group was induced to prefer dietary foods and to avoid fattening foods. The second experimental group was induced to prefer fattening food and to avoid dietary food. &lt;br /&gt; &lt;b&gt;Results&lt;/b&gt;&lt;br /&gt; Experimental group 1 chose dietary products and avoided fattening items more often than group 2. We observed the increased importance of goals to lose weight and improve body shape as a result of manipulation consistent with its direction.&lt;br /&gt; &lt;br /&gt; &lt;b&gt;Conclusions&lt;/b&gt;&lt;br /&gt; Implicit manipulation of food preferences by approach/avoidance tasks can alter food preferences and attitudes.

Moderate intensity treadmill exercise alters food preference via dopaminergic plasticity of ventral tegmental area-nucleus accumbens in obese mice

Obesity has been associated with the excessive intake of palatable food as well as physical inactivity. To investigate the neurobiological mechanism underlying the exercised-induced prevention and treatment of obesity, the present study examined the effect of treadmill exercise on the preference for palatable food in mice. Levels of tyrosine hydroxylase (TH) in the ventral tegmental area-nucleus accumbens system were also analysed, as well as levels of dopamine, dopamine transporter, and D2 receptors in the nucleus accumbens. Forty C57BL/6J mice were randomly divided into a control group (CG, n=10) and a high-fat diet group (HG, N=30). Mice of the HG group were fed a high-fat diet for 12 weeks in order to induce a model of obesity, following which the obese mice were randomly divided into an obese control group (OG, n=11) and an obese+exercise group (OEG, n=12). OEG mice received 8 weeks of treadmill exercise intervention. Our results indicate that, relative to animals in the OG group, OEG mice exhibited significant decreases in the preference for high-fat diets and insulin resistance, along with increases in the preference for sucrose and milk, TH and D2 receptor expression, and levels of dopamine in the ventral tegmental area-nucleus accumbens system. These results suggest that moderate-intensity treadmill exercise can alter food preference in obese mice, which may be mediated by dopaminergic plasticity of the ventral tegmental area-nucleus accumbens and enhanced insulin sensitivity.

Control of Appetite and Food Preference by NMDA Receptor and Its Co-Agonist d-Serine.

Obesity causes a significant negative impact on health of human beings world-wide. The main reason for weight gain, which eventually leads to obesity, is excessive ingestion of energy above the body’s homeostatic needs. Therefore, the elucidation of detailed mechanisms for appetite control is necessary to prevent and treat obesity. N-methyl-d-aspartate (NMDA) receptor is a post-synaptic glutamate receptor and is important for excitatory neurotransmission. It is expressed throughout the nervous system, and is important for long-term potentiation. It requires both ligand (glutamate) and co-agonist (d-serine or glycine) for efficient opening of the channel to allow calcium influx. d-serine is contained in fermented foods and marine invertebrates, and brain d-serine level is maintained by synthesis in vivo and supply from food and gut microbiota. Although the NMDA receptor has been reported to take part in the central regulation of appetite, the role of d-serine had not been addressed. We recently reported that exogenous d-serine administration can suppress appetite and alter food preference. In this review, we will discuss how NMDA receptor and its co-agonist d-seine participate in the control of appetite and food preference, and elaborate on how this system could possibly be manipulated to suppress obesity.