Previous research, restricted to the laboratory, has found that restrained eaters overeat after they violate their diet. However, there has been no evidence showing that this same process occurs outside the lab. We hypothesized that outside of this artificial setting, restrained eaters would be able to control their eating. In Study 1, 127 participants reported hourly on their diet violations and eating over 2 days. In Study 2, 89 participants tracked their intake for 8 days, and 50 of these participants consumed a milk shake (a diet violation) on Day 7, as part of an ostensibly unrelated study. As hypothesized, dieters did not overeat following violations of their diet in either study. These findings are in contrast with those of previous lab studies and dispel the widely held belief that diet violations lead to overeating in everyday life.

Background

Corticotropin-releasing hormone receptor 1 (CRH-R1) in the amygdala and the stria terminalis plays an important role in the activation of central stress circuits. Genetic factors may contribute to the hyperresponsiveness of these circuits in irritable bowel syndrome (IBS).

Aims

To determine if CRH-R1 SNPs are associated with: (1) a diagnosis of IBS, (2) gastrointestinal (GI) symptoms, and (3) acoustic startle response (ASR) to threat, which is mediated by the amygdala via CRH.

Methods

Three CRH-R1 SNPS (rs110402, rs242924, and rs7209436) were genotyped using salivary DNA from IBS and healthy control subjects (HCs). Eye blink ASR was obtained during safe (no shock), anticipation (abdominal shock may soon occur) and threat (abdominal shock likely) conditions in a subset of subjects. Associations between each SNP with IBS status, clinical traits and ASR were measured.

Results

235 IBS patients (mean age 37.5 yrs, 74% F) and 264 HCs (mean age 32.1 yrs, 70% F) were studied. Of these, 57 IBS and 41 HCs underwent the ASR protocol. The presence of IBS was associated with the major allele for all three CRH-R1 SNPs (p=0.009-0.025). Within IBS, the major allele for all three SNPs (p=0.017-0.065) was associated with GI symptom anxiety scores. Within subjects with at least one copy of the major allele for the CRH-R1 SNPs, IBS had significantly lower ASR compared to HCs during threat conditions (p=0.001-0.002). Within IBS, CRH-R1 SNPs were associated with a graded increase in ASR to threat (p=0.007-0.008).

Conclusion

These findings support that CRH-R1 contributes to the dysregulated stress responsiveness in IBS.

Background

Irritable bowel syndrome (IBS) is a stress-sensitive disorder of brain-gut interactions associated with a higher prevalence of early adverse life events (EALs). However, it is incompletely understood how trauma severity or disclosure influence the risk of developing IBS or symptom severity.

Aims

To determine whether (1) IBS patients report a greater number of EALs compared with healthy controls; (2) trauma severity and first age of EAL increase the odds of IBS; (3) confiding in others reduces the odds of IBS; (4) the number, trauma severity, and first age of EAL are associated with symptom severity; (5) sex differences exist.

Methods

In total, 197 IBS patients (72% women, mean age=30.28 y) and 165 healthy controls (59% women, mean age=30.77 y) completed the Childhood Traumatic Events Scale, measuring severity of EALs and degree of confiding in others. Regression analyses were used to predict IBS status from EALs and association between gastrointestinal symptoms and EALs.

Results

A greater number of EALs [odds ratio (OR)=1.36, 95% confidence interval (CI), 1.14-1.62; P<0.001] and higher perceived trauma severity (OR=1.13, 95% CI, 1.08-1.19; P<0.001) were associated with increased odds of IBS. Confiding in others decreased the odds of having IBS (OR=0.83, 95% CI, 0.72-0.96; P=0.012). The first age of EAL was not predictive of IBS. No sex differences were found.

Conclusions

Assessing the traumatic severity of EALs and amount of confiding in others is important as they can affect the risk of having IBS. Our findings emphasize early intervention to improve health outcomes in individuals with EALs.

Objective

Weight loss surgery results in significant changes in the anatomy, function, and intraluminal environment of the gastrointestinal tract affecting the gut microbiome. Although bariatric surgery results in sustained weight loss, decreased appetite, and hedonic eating, it is unknown whether the surgery-induced alterations in gut microbiota play a role in the observed changes in hedonic eating. We explored the following hypotheses: (1) laparoscopic sleeve gastrectomy (LSG) results in changes in gut microbial composition; (2) alterations in gut microbiota are related to weight loss; (3) alterations in gut microbiome are associated with changes in appetite and hedonic eating.

Methods

Eight obese women underwent LSG. Their body mass index, body fat mass, food intake, hunger, hedonic eating scores, and stool samples were obtained at baseline and 1-month postsurgery. 16S ribosomal RNA gene sequencing was performed on stool samples. DESeq2 changes in microbial abundance. Multilevel-sparse partial least squares discriminant analysis was applied to genus-level abundance for discriminative microbial signatures.

Results

LSG resulted in significant reductions in body mass index, food intake, and hedonic eating. A microbial signature composed of five bacterial genera discriminated between pre- and postsurgery status. Several bacterial genera were significantly associated with weight loss (Bilophila, q = 3E-05; Faecalibacterium q = 4E-05), lower appetite (Enterococcus, q = 3E-05), and reduced hedonic eating (Akkermansia, q = .037) after surgery.

Conclusions

In this preliminary analysis, changes in gut microbial abundance discriminated between pre- and postoperative status. Alterations in gut microbiome were significantly associated with weight loss and with reduced hedonic eating after surgery; however, a larger sample is needed to confirm these findings.

OBJECTIVE:This study aimed to characterize obesity-related sex differences in the intrinsic activity and connectivity of the brain's reward networks. METHODS:Eighty-six women (n = 43) and men (n = 43) completed a 10-minute resting functional magnetic resonance imaging scan. Sex differences and commonalities in BMI-related frequency power distribution and reward seed-based connectivity were investigated by using partial least squares analysis. RESULTS:For whole-brain activity in both men and women, increased BMI was associated with increased slow-5 activity in the left globus pallidus (GP) and substantia nigra. In women only, increased BMI was associated with increased slow-4 activity in the right GP and bilateral putamen. For seed-based connectivity in women, increased BMI was associated with reduced slow-5 connectivity between the left GP and putamen and the emotion and cortical regulation regions, but in men, increased BMI was associated with increased connectivity with the medial frontal cortex. In both men and women, increased BMI was associated with increased slow-4 connectivity between the right GP and bilateral putamen and the emotion regulation and sensorimotor-related regions. CONCLUSIONS:The stronger relationship between increased BMI and decreased connectivity of core reward network components with cortical and emotion regulation regions in women may be related to the greater prevalence of emotional eating. The present findings suggest the importance of personalized treatments for obesity that consider the sex of the affected individual.