Weight Regain and Ingestive Behavior in Women after Metabolic Surgery.

This study investigated associations between maladaptive ingestive behaviors and weight regain in women who underwent metabolic surgery 2-10 years ago. Using a web-based survey, we assessed emotional, external, and restrained eating (Dutch Eating Behavior Questionnaire-DEBQ), food cravings (Food-Craving Inventory-FCI), and other behaviors (e.g., Eating Disorder Examination Questionnaire-EDE-Q; Alcohol Use Disorder Identification Test-Concise-AUDIT-C) in 36 women (42.9 ± 9.5 years old) post-surgery. We found that weight regain was specifically associated with increased frequency of cravings for sweets (r = 0.43), higher global scores in the EDE-Q (r = 0.38), and time elapsed since surgery (r = 0.35; all p's < 0.04). Multiple regression analysis revealed that the association between weight regain and sweet cravings interacted with time after surgery (p = 0.04), with the strongest association observed in women assessed closer to the surgery (i.e., 2.0-2.8 years). The combination of time after surgery and its interaction with sweet cravings accounted for 31% of the individual variations in weight regain (p = 0.005). Notably, among participants who reported alcohol consumption (31 of 36), 55% had an AUDIT-C score indicating hazardous drinking. These findings highlight the relevance of attending to patients' reports of frequent sweet cravings and screening for alcohol use to enhance strategies tailored to prevent weight regain and alcohol-related health problems post-surgery.

Fat-free mass accounts for most of the variance in alcohol elimination rate in women.

BACKGROUND: Understanding how blood alcohol concentrations (BAC) achieved after drinking are determined is critical to predicting alcohol exposure to the brain and other organs and alcohol's effects. However, predicting end-organ exposures is challenging, as there is wide variation in BAC achieved after drinking a specified volume of alcohol. This variation is partly due to differences in body composition and alcohol elimination rates (AER), but there are limited data on how obesity affects AER. Here, we assess associations between obesity, fat-free mass (FFM), and AER in women and examine whether bariatric surgeries, which are linked to an increased risk of alcohol misuse, affect these associations. METHODS: We analyzed data from three studies that used similar intravenous alcohol clamping procedures to estimate AER in 143 women (21 to 64 years old) with a wide range of body mass index (BMI; 18.5 to 48.4 kg/m2 ). Body composition was measured in a subgroup using dual-energy X-ray absorptiometry (n = 42) or Bioimpedance (n = 60), and 19 of the women underwent bariatric surgery 2.1 ± 0.3 years before participation. We analyzed data using multiple linear regression analyses. RESULTS: Obesity and older age were associated with a faster AER (BMI: rs  = 0.70 and age: rs  = 0.61, both p < 0.001). Compared to women with normal weight, AER was 52% faster (95% Confidence Interval: 42% to 61%) in women with obesity. However, BMI lost predictive value when adding fat-free mass (FFM) to the regression model. Age, FFM, and its interaction explained 72% of individual variance in AER (F (4, 97) = 64.3, p < 0.001). AER was faster in women with higher FFM, particularly women in the top tertile of age. After controlling for FFM and age, bariatric surgery was not associated with differences in AER (p = 0.74). CONCLUSIONS: Obesity is associated with a faster AER, but this association is mediated by an obesity-related increase in FFM, particularly in older women. Previous findings of a reduced alcohol clearance following bariatric surgery compared with prior to surgery are likely explained by a reduction in FFM post-surgery.

Enhancement of taste by retronasal odors in patients with Wolfram syndrome and decreased olfactory function.

Wolfram syndrome is a rare disease characterized by diabetes, neurodegeneration, loss of vision, and audition. We recently found, in a young sample of participants (mean age 15 years), that Wolfram syndrome was associated with impairment in smell identification with normal smell sensitivity and whole-mouth taste function. However, these senses were assessed separately, and it is unknown whether smell-taste interactions are altered in Wolfram syndrome, which was the focus of this study. Participants with Wolfram syndrome (n = 36; 18.2 ± 6.8 years) and sex-age-equivalent healthy controls (n = 34) were assessed with a battery of sensory tests. Using sip-and-spit methods, participants tasted solutions containing gustatory and olfactory stimuli (sucrose with strawberry extract, citric acid with lemon extract, sodium chloride in vegetable broth, and coffee) with and without nose clips, and rated perceived taste and retronasal smell intensities using the generalized Labeled Magnitude Scale. Participants also completed n-butanol detection thresholds and the University of Pennsylvania Smell Identification Test (UPSIT). Retronasal smell increased taste intensity of sucrose, sodium chloride, and coffee solutions similarly in both groups (P values <0.03). Compared with the control group, participants in the Wolfram group had lower UPSIT scores and reduced smell sensitivity, retronasal intensity, and saltiness (P values <0.03), but rated other taste intensities similarly when wearing the nose clip. Despite impairments in orthonasal smell identification, odor-induced taste enhancement was preserved in participants with Wolfram syndrome who still had some peripheral olfactory function. This finding suggests that odor-induced taste enhancement may be preserved in the presence of reduced olfactory intensity.

Taste and Smell Function in Head and Neck Cancer Survivors.

Survivors of head and neck squamous cell cancers (HNSCC) frequently complain of taste dysfunction long after radiation therapy is completed, which contradicts findings from most sensory evaluation studies that predict dysfunction should resolve few months after treatment. Therefore, it remains unclear whether taste and smell function fully recovers in HNSCC survivors. We evaluated HNSCC survivors (n = 40; age 63 ± 12 years, mean ± standard deviation) who received radiation therapy between 6 months and 10 years before recruitment and compared their responses to those of a healthy control group (n = 20) equivalent in age, sex, race, smoking history, and body mass index. We assessed regional (tongue tip) and whole-mouth taste intensity perception using the general Labeled Magnitude Scale and smell function using the University of Pennsylvania Smell Identification Test (UPSIT). To determine possible differences between groups in retronasal smell perception, we used solutions of sucrose with strawberry extract, citric acid with lemon extract, sodium chloride in vegetable broth, and caffeine in coffee and asked participants to rate perceived smell and taste intensities with and without nose clips. We found groups had similar UPSIT and taste intensity scores when solutions were experienced in the whole mouth. However, HNSCC survivors were less likely to identify low concentrations of bitter, sweet, or salty stimuli in the tongue tip relative to healthy controls. Our findings suggest persistent and subtle localized damage to the chorda tympani or to the taste buds in the fungiform papillae of HNSCC survivors, which could explain their sensory complaints long after completion of radiotherapy.

Changes of Taste, Smell and Eating Behavior in Patients Undergoing Bariatric Surgery: Associations with PROP Phenotypes and Polymorphisms in the Odorant-Binding Protein OBPIIa and CD36 Receptor Genes.

Bariatric surgery is the most effective long-term treatment for severe obesity and related comorbidities. Although patients who underwent bariatric surgery report changes of taste and smell perception, results from sensory studies are discrepant and limited. Here, we assessed taste and smell functions in 51 patients before, one month, and six months after undergoing bariatric surgery. We used taste strip tests to assess gustatory function (including sweetness, saltiness, sourness, umaminess, bitterness and oleic acid, a fatty stimulus), the "Sniffin' Sticks" test to assess olfactory identification and the 3-Factor Eating Questionnaire to assess eating behavior. We also explored associations between these phenotypes and flavor-related genes. Results showed an overall improvement in taste function (including increased sensitivity to oleic acid and the bitterness of 6-n-propylthiouracil (PROP)) and in olfactory function (which could be related to the increase in PROP and oleic acid sensitivity), an increase in cognitive restraint, and a decrease in disinhibition and hunger after bariatric surgery. These findings indicate that bariatric surgery can have a positive impact on olfactory and gustatory functions and eating behavior (with an important role of genetic factors, such PROP tasting), which in turn might contribute to the success of the intervention.

Relationship between Sucrose Taste Detection Thresholds and Preferences in Children, Adolescents, and Adults.

To address gaps in knowledge, our objectives were to (1) to determine whether there are age-related changes in sweet taste detection thresholds, as has been observed for sweet taste preferences, and (2) determine whether detection thresholds and taste preferences were significantly related to each other from childhood to adulthood. We combined data from studies that used the same validated psychophysical techniques to measure sucrose taste detection threshold and the most preferred sucrose concentration in children (n = 108), adolescents (n = 172), and adults (n = 205). There were significant effects of age group on both sucrose detection thresholds (p < 0.001) and most preferred sucrose concentration (p < 0.001). While children had higher sucrose detection thresholds than adolescents, who in turn tended to have higher detection thresholds than adults, both children and adolescent most preferred sucrose concentrations were higher than that of adults (all p < 0.05). Among each age group, and when combined, the lowest sucrose concentration detected was not significantly correlated with the most preferred sucrose concentration (all p > 0.18). These data provide further evidence that age-related changes in sucrose taste preferences that occur during adolescence cannot be explained by changes in taste sensitivity and that these two dimensions of sweet taste undergo distinct developmental trajectories from childhood to adulthood.

Alcohol sensitivity in women after undergoing bariatric surgery: a cross-sectional study.

BACKGROUND: Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG), the most common bariatric surgeries performed worldwide, increase the risk to develop an alcohol use disorder. This might be due, in part, to surgery-related changes in alcohol pharmacokinetics. Another risk factor, unexplored within this population, is having a reduced subjective response to alcohol's sedative effects. OBJECTIVES: To assess whether the alcohol sensitivity questionnaire (ASQ), a simple self-report measure, could pinpoint reduced alcohol sensitivity in the bariatric population. SETTING: University medical centers in Missouri and Illinois. METHODS: Women who had RYGB (n = 16), SG (n = 28), or laparoscopic adjustable gastric banding surgery (n = 11) within the last 5 years completed the ASQ for both pre- and postsurgical timeframes, and 45 of them participated in oral alcohol challenge testing postsurgery. Blood alcohol concentration (BAC) and subjective stimulation and sedation were measured before and for 3.5 hours after drinking. RESULTS: In line with faster and higher peak BACs after RYGB and SG than laparoscopic adjustable gastric banding surgery (P < .001), postsurgery ASQ scores were more reduced from presurgery scores after RYGB/SG than after laparoscopic adjustable gastric banding surgery (-2.3 ± .3 versus -1.2 ± .2; P < .05). However, despite the dramatic changes in BAC observed when ingesting alcohol after RYGB/SG surgeries, which resulted in peak BAC that were approximately 50% above the legal driving limit, a third of these women felt almost no alcohol-related sedative effects. CONCLUSIONS: Although RYGB/SG dramatically increased sensitivity to alcohol in all participants, meaningful interindividual differences remained. The ASQ might help identify patients at increased risk to develop an alcohol use disorder after surgery.

Effect of alcohol ingestion on plasma glucose kinetics after Roux-en-Y gastric bypass surgery.

BACKGROUND: Roux-en-Y gastric bypass surgery (RYGB) increases the rate of alcohol absorption so that peak blood alcohol concentration is 2-fold higher after surgery compared with concentrations reached after consuming the same amount presurgery. Because high doses of alcohol can lead to hypoglycemia, patients may be at increased risk of developing hypoglycemia after alcohol ingestion. OBJECTIVES: We conducted 2 studies to test the hypothesis that the consumption of approximately 2 standard drinks of alcohol would decrease glycemia more after RYGB than before surgery. SETTING: Single-center prospective randomized trial. METHODS: We evaluated plasma glucose concentrations and glucose kinetics (assessed by infusing a stable isotopically labelled glucose tracer) after ingestion of a nonalcoholic drink (placebo) or an alcoholic drink in the following groups: (1) 5 women before RYGB (body mass index = 43 ± 5 kg/m2) and 10 ± 2 months after RYGB (body mass index = 31 ± 7 kg/m2; study 1), and (2) 8 women who had undergone RYGB surgery 2.2 ± 1.2 years earlier (body mass index = 30 ± 5 kg/m2; study 2) RESULTS: Compared with the placebo drink, alcohol ingestion decreased plasma glucose both before and after surgery, but the reduction was greater before (glucose nadir placebo = -.4 ± 1.0 mg/dL versus alcohol = -9.6 ± 1.5 mg/dL) than after (glucose nadir placebo = -1.0 ± 1.6 mg/dL versus alcohol = -5.5 ± 2.6 mg/dL; P < .001) surgery. This difference was primarily due to an alcohol-induced early increase followed by a subsequent decrease in the rate of glucose appearance into systemic circulation. CONCLUSION: RYGB does not increase the risk of hypoglycemia after consumption of a moderate dose of alcohol.

Sleeve gastrectomy surgery: when 2 alcoholic drinks are converted to 4.

BACKGROUND: While it is well established that Roux-en-Y gastric bypass (RYGB) causes a rapid and heightened peak blood alcohol concentration (BAC), results from previous studies on the effects of sleeve gastrectomy (SG) on alcohol pharmacokinetics are conflicting. Data from 2 studies found SG did not affect BAC, whereas another study found SG caused a heightened peak BAC after alcohol ingestion. Moreover, these 3 studies estimated BAC from breathalyzers, which might not reliably estimate peak BAC. OBJECTIVES: The aims of this study were to evaluate (1) the effect of SG, relative to RYGB and a presurgery group, on alcohol pharmacokinetics and subjective effects, and (2) whether breathalyzers are reliable in this population. SETTING: Single-center prospective nonrandomized trial. METHODS: We performed alcohol challenge tests in 11 women who had SG surgery 1.9 ± .1 years ago (body mass index = 35.1 ± 6.6 kg/m2), 8 women who had RYGB surgery 2.2 ± .4 years ago (body mass index = 30.0 ± 5.2 kg/m2), and 9 women who were scheduled for bariatric surgery (body mass index = 44.1 ± 4.0 kg/m2). BACs were estimated from breath samples and measured by gas chromatography at various times after consuming approximately 2 standard drinks. RESULTS: BAC increased faster, peak BAC was approximately 2-fold higher, and feelings of drunkenness were heightened in both SG and RYGB groups relative to the presurgery group (P values<.001). BAC estimated from breath samples underestimated BAC by 27% (standard deviation = 13%) and missed peak BACs postsurgery. CONCLUSIONS: SG, similar to RYGB, causes marked alterations in the response to alcohol ingestion manifested by a faster and higher peak BAC. The breathalyzer is invalid to assess effects of gastric surgeries on pharmacokinetics of ingested alcohol.

Effects of Sleeve Gastrectomy vs. Roux-en-Y Gastric Bypass on Eating Behavior and Sweet Taste Perception in Subjects with Obesity.

The goal of this study was to test the hypothesis that weight loss induced by Roux-en-Y gastric bypass (RYGB) has greater effects on taste perception and eating behavior than comparable weight loss induced by sleeve gastrectomy (SG). We evaluated the following outcomes in 31 subjects both before and after ~20% weight loss induced by RYGB (n = 23) or SG (n = 8): (1) sweet, savory, and salty taste sensitivity; (2) the most preferred concentrations of sucrose and monosodium glutamate; (3) sweetness palatability, by using validated sensory testing techniques; and (4) eating behavior, by using the Food Craving Inventory and the Dutch Eating Behavior Questionnaire. We found that neither RYGB nor SG affected sweetness or saltiness sensitivity. However, weight loss induced by either RYGB or SG caused the same decrease in: (1) frequency of cravings for foods; (2) influence of emotions and external food cues on eating behavior; and (3) shifted sweetness palatability from pleasant to unpleasant when repetitively tasting sucrose (all p-values ≤ 0.01). Therefore, when matched on weight loss, SG and RYGB cause the same beneficial effects on key factors involved in the regulation of eating behavior and hedonic component of taste perception.

Structure-function of CD36 and importance of fatty acid signal transduction in fat metabolism.

CD36 (cluster of differentiation 36) is a scavenger receptor that functions in high-affinity tissue uptake of long-chain fatty acids (FAs) and contributes under excessive fat supply to lipid accumulation and metabolic dysfunction. This review describes recent evidence regarding the CD36 FA binding site and a potential mechanism for FA transfer. It also presents the view that CD36 and FA signaling coordinate fat utilization, a view that is based on newly identified CD36 actions that involve oral fat perception, intestinal fat absorption, secretion of the peptides cholecystokinin and secretin, regulation of hepatic lipoprotein output, activation of beta oxidation by muscle, and regulation of the production of the FA-derived bioactive eicosanoids. Thus abnormalities of fat metabolism and the associated pathology might involve dysfunction of CD36-mediated signal transduction in addition to the changes in FA uptake.

Bariatric surgery-induced weight loss causes remission of food addiction in extreme obesity.

OBJECTIVE: To test the hypotheses that bariatric surgery-induced weight loss: induces remission of food addiction (FA), and normalizes other eating behaviors associated with FA. METHODS: Forty-four obese subjects (BMI= 48 ± 8 kg/m(2) ) were studied before and after ∼20% weight loss induced by bariatric surgery (25 Roux-en-Y gastric bypass, 11 laparoscopic adjustable gastric banding, and eight sleeve gastrectomy). We assessed: FA (Yale Food Addiction Scale), food cravings (Food Craving Inventory), and restrictive, emotional and external eating behaviors (Dutch Eating Behavior Questionnaire). RESULTS: FA was identified in 32% of subjects before surgery. Compared with non-FA subjects, those with FA craved foods more frequently, and had higher scores for emotional and external eating behaviors (all P-values <0.01; all Cohen's d >0.8). Surgery-induced weight loss resulted in remission of FA in 93% of FA subjects; no new cases of FA developed after surgery. Surgery-induced weight loss decreased food cravings, and emotional and external eating behaviors in both groups (all P-values < 0.001; all Cohen's d ≥ 0.8). Restrictive eating behavior did not change in non-FA subjects but increased in FA subjects (P < 0.01; Cohen's d>1.1). CONCLUSION: Bariatric surgery-induced weight loss induces remission of FA and improves several eating behaviors that are associated with FA.

Cigarette smoking and obesity are associated with decreased fat perception in women.

OBJECTIVE: Smoking and obesity are independently associated with high consumption of high-fat foods in women. We tested whether the co-occurrence of smoking and obesity associates with reduced oral fat perception. METHODS: Four groups of women (14 obese smokers, 11 obese never-smokers, 10 normal-weight smokers, 12 normal-weight never-smokers) rated vanilla puddings that varied in fat content for perceived intensity of creaminess and sweetness, using the general Labeled Magnitude Scale (gLMS), and degree of pleasantness, using the hedonic gLMS. To determine the role of retronasal smell, subjects rated puddings with and without noseclips. RESULTS: For all groups, perception of creaminess grew with increasing fat concentrations; puddings with any amount of fat were perceived as sweeter than fat-free pudding, and sweetness was enhanced when tasted without noseclips. Overall, obese smokers perceived less creaminess, sweetness, and pleasure while tasting the puddings than did the other three groups (all P values < 0.02). CONCLUSION: The ability to perceive fat and sweetness in and derive pleasure from foods is particularly compromised in obese women who smoke, which could contribute to excess calorie intake in this population already at high risk for cardiovascular and metabolic disease. Retronasal olfaction appears not to contribute to blunted flavor perception observed in obese smokers.

Changes in taste perception and eating behavior after bariatric surgery-induced weight loss in women.

OBJECTIVE: Roux-en-Y gastric bypass (RYGB) surgery causes greater weight loss than laparoscopic adjustable gastric banding (LAGB). We tested the hypothesis that RYGB has weight loss-independent effects on taste perception, which influence eating behavior and contribute to the greater weight loss. METHODS: Subjects were studied before and after ∼20% weight loss induced by RYGB (n = 17) or LAGB (n = 10). The following have been evaluated: taste sensitivity for sweet, salty and savory stimuli, sucrose and monosodium glutamate (MSG) preferences, sweetness palatability, eating behavior, and expression of taste-related genes in biopsies of fungiform papillae. RESULTS: Weight loss induced by both procedures caused the same decrease in: preferred sucrose concentration (-12 ± 10%), perceived sweetness of sucrose (-7 ± 5%), cravings for sweets and fast-foods (-22 ± 5%), influence of emotions (-27 ± 5%), and external food cues (-30 ± 4%) on eating behavior, and expression of α-gustducin in fungiform papillae (all P values <0.05). RYGB, but not LAGB, shifted sweetness palatability from pleasant to unpleasant when repetitively tasting sucrose (P = 0.05). Neither procedure affected taste detection thresholds nor MSG preferences. CONCLUSIONS: LAGB and RYGB cause similar alterations in eating behaviors, when weight loss is matched. These changes in eating behavior were not associated with changes in taste sensitivity, suggesting other, as yet unknown, mechanisms are involved.

The fatty acid translocase gene CD36 and lingual lipase influence oral sensitivity to fat in obese subjects.

The precise orosensory inputs engaged for dietary lipids detection in humans are unknown. We evaluated whether a common single nucleotide polymorphism (rs1761667) in the CD36 gene that reduces CD36 expression and the addition of orlistat, a lipase inhibitor, to reduce FA release from triacylglycerols (TGs), the main component of dietary fats, would attenuate fat orosensory sensitivity in humans. Twenty-one obese subjects with different rs1761667 genotypes (6 AA, 7 AG, and 8 GG) were studied on two occasions in which oleic acid and triolein orosensory detection thresholds were measured using emulsions prepared with and without orlistat. Subjects homozygous for the G-allele had 8-fold lower oral detection thresholds for oleic acid and triolein than subjects homozygous for the A allele, which associates with lower CD36 expression (P = 0.03). Thresholds for heterozygous subjects were intermediate. The addition of orlistat increased detection thresholds for triolein (log threshold = -0.3 ± 0.2 vs. 0.3 ± 0.1; P < 0.001) but not oleic acid (log threshold = -1.0 ± 0.2 vs. -0.8 ± 0.2; P > 0.2). In conclusion, this is the first experimental evidence for a role of CD36 in fat gustatory perception in humans. The data also support involvement of lingual lipase and are consistent with the concept that FA and not TG is the sensed stimulus.

Psychophysical dissection of genotype effects on human bitter perception.

The purpose of this study was to define the effects of individual polymorphisms within the haplotypes of the TAS2R38 taste receptor gene on human bitter taste perception. A racially and ethnically diverse sample of children and adults (N = 980) was phenotyped for thresholds of 6-n-propylthiouracil (PROP) and genotyped for 3 polymorphisms of the TAS2R38 gene (A49P, V262A, I296V). Subjects were grouped according to their diplotype (i.e., specific combinations of haplotypes) and compared for PROP thresholds. By contrasting subjects with particular diplotypes, we found that in addition to A49P, V262A and I296V were related to the ability of the subjects to detect PROP. The V262A variant site affected the ability of subjects to detect mid-range concentrations of PROP, whereas the I296V variant site affected the ability of subjects to perceive PROP at the lowest concentration. These data agree with results from previous studies using cell-based assays for 2 variant sites (A49P and V262A) but not those for the I296V variant site. The reason for the discordant results is not known but it highlights the need for psychophysical as well as cell-based methods to understand the genotype-phenotype relationship for taste receptors. Human PROP sensitivity is determined by the combination of each of these 3 polymorphisms within the TAS2R38 gene.

Breastfeeding and prolactin levels in lactating women with a family history of alcoholism.

OBJECTIVE: Many motivated new mothers fail to reach public health goals for breastfeeding, highlighting the need to identify risk factors. Because having a family history of alcoholism is associated with blunted prolactin responses to an alcohol challenge in nonlactating individuals, this study aimed to identify associations in family history of alcoholism, prolactin, and breastfeeding behaviors in lactating women. METHODS: This was a 2-day experimental study that used within-subject alcohol or control beverage consumption and between-subject family history of alcoholism factors. The participants were non-alcohol-dependent lactating women; 7 were family history-positive (FHP) for alcohol dependence, and 21 were family history-negative (FHN). Consumption of 0.4 g/kg alcohol or nonalcoholic beverage occurred in separate randomized sessions, followed by use of a breast pump. Basal and suckling-induced prolactin, blood alcohol concentrations, milk yield, self-reported drug effects, neophobia, and breastfeeding patterning were measured. RESULTS: Although no group differences in alcohol pharmacokinetics were detected, FHP women exhibited blunted prolactin to breast stimulation after drinking the control and alcohol beverage and felt more of the stimulant-like effects of alcohol than did FHN women. FHP women reported more frequent daily breastfeeding than did FHN women. CONCLUSIONS: This is the first evidence that family history of alcoholism is associated with a blunted magnitude, rapidity, and duration of the prolactin response to breast stimulation and an alcohol challenge in lactating women. More frequent breastfeeding by FHP women suggests behavioral compensation for perceived and/or actual poor lactation. Alcohol did not enhance lactational performance, further disputing the lore that alcohol is a galactagogue.