Altered brain-derived neurotrophic factor blood levels and gene variability are associated with anorexia and bulimia

Murine models and association studies in eating disorder (ED) patients have shown a role for the brain-derived neurotrophic factor (BDNF) in eating behavior. Some studies have shown association of BDNF -270C/T single-nucleotide polymorphism (SNP) with bulimia nervosa (BN), while BDNF Val66Met variant has been shown to be associated with both BN and anorexia nervosa (AN). To further test the role of this neurotrophin in humans, we screened 36 SNPs in the BDNF gene and tested for their association with ED and plasma BDNF levels as a quantitative trait. We performed a family-based association study in 106 ED nuclear families and analyzed BDNF blood levels in 110 ED patients and in 50 sib pairs discordant for ED. The rs7124442T/rs11030102C/rs11030119G haplotype was found associated with high BDNF levels (mean BDNF TCG haplotype carriers = 43.6 ng/ml vs. mean others 23.0 ng/ml, P = 0.016) and BN (Z = 2.64; P recessive = 0.008), and the rs7934165A/270T haplotype was associated with AN (Z =-2.64; P additive = 0.008). The comparison of BDNF levels in 50 ED discordant sib pairs showed elevated plasma BDNF levels for the ED group (mean controls = 41.0 vs. mean ED = 52.7; P = 0.004). Our data strongly suggest that altered BDNF levels modulated by BDNF gene variability are associated with the susceptibility to ED, providing physiological evidence that BDNF plays a role in the development of AN and BN, and strongly arguing for its involvement in eating behavior and body weight regulation.     

Shifts in patterns and consumption of beverages between 1965 and 2002

Background: Beverage patterning may play a role in partially explaining the rising rates of obesity in the United States, yet little work on overall trends and patterns exits. Our objective was to examine trends and patterns of beverage consumption among U.S. adults. Methods: We used data from the nationally representative Nationwide Food Consumption Surveys (1965, 1977 to 1978) and the National Health and Nutrition Surveys (1988 to 1994, 1999 to 2002). To examine trends we determined percent consuming and per capita and per consumer caloric intake from all beverages. We used cluster analysis to determine year‐specific beverage patterns in 1977 and 2002. Results: The percentage of calories from beverages significantly increased between 1965 (11.8%), 1977 (14.2%), 1988 (18.5%), and 2002 (21.0%); this represents an overall increase of 222 calories per person per day from beverages, resulting largely from increased intake of calorically sweetened beverages. Beverage patterns in 2002 were more complex than in 1977 and were dominated by a greater number of beverages, reflecting the increase in alcohol, soda, and diet beverages. Conclusion: Calories from beverages increased substantially from 1965 to 2002, providing a considerable source of daily calories. Given the upward trends in calorically sweetened, nutrient‐deficient beverages and the shifts in overall beverage patterns, addressing beverage intake is a salient issue for adults.     

Binge eating disorder and night eating syndrome in adults with type 2 diabetes

Objective: To determine the prevalence of binge eating disorder (BED) and night eating syndrome (NES) among applicants to the Look AHEAD (Action for Health in Diabetes) study. Research Methods and Procedures: The Eating Disorders Examination–Questionnaire (EDE‐Q) and the Night Eating Questionnaire (NEQ) were used to screen patients. Phone interviews were conducted using the EDE for those who reported at least eight episodes of objective binge eating in the past month and using the Night Eating Syndrome History and Interview for those who scored ≥25 on the NEQ. Recruitment at four sites (Birmingham, n = 200; Houston, n = 259; Minneapolis, n = 182; and Philadelphia, n = 204) yielded 845 participants (58% women; mean age = 60.1 ± 6.7 years; mean BMI = 36.2 ± 6.3 kg/m²). Results: Screening scores were met by 47 (5.6%) applicants on the EDE‐Q and 71 (8.4%) on the NEQ. Of the 85% (40/47) who completed the EDE interview, 12 were diagnosed with BED, representing 1.4% of the total sample. Of the 72% (51/71) who completed the Night Eating Syndrome History and Interview, 32 were diagnosed with NES, equal to 3.8% of the total sample. Three participants had both BED and NES. Participants with eating disorders were younger, heavier, and reported more eating pathology than those without eating disorders. Discussion: Among obese adults with type 2 diabetes, NES was reported more frequently than BED, which, in turn, was less common than expected.     

Overeating by young obesity-prone and lean rats caused by tastes associated with low energy foods

Objective: Childhood obesity is a prominent health problem that may involve early learning about tastes and the energy content of foods. We tested the hypothesis that food tastes predictive of low energy content cause overeating in young animals. Research Methods and Procedures: Juvenile and adolescent (4‐ and 8‐week‐old) male JCR:LA‐cp lean (+/cp or +/+) and obesity‐prone (cp/cp) rats were given sweet (saccharin) and salty (sodium chloride) gelatin cubes made with starch (high caloric) or no starch (low caloric) for 16 days of taste conditioning. After 10 hours of food deprivation, rats received pre‐meals with flavors that had been paired or unpaired with high caloric content during taste conditioning, followed immediately by measurement of chow intake at regular meals. Results: Our findings show that both lean (+/cp) and obesity‐prone (cp/cp) juvenile rats ate more regular chow after a pre‐meal with a flavor associated with low caloric value than after a similar pre‐meal with a flavor predictive of high caloric content. This effect occurred with juvenile rats but not with adolescents. Discussion: Data from our study indicate that the subversion of the relationship between taste and caloric content disrupts the normal physiological and behavioral energy balance of juvenile rats, resulting in overeating that is independent of genetic disposition for obesity.     

Psychosocial and physical impairment in overweight adolescents at high risk for eating disorders

Objective: Many overweight adolescents display elevated risk for the development of eating disorders, as seen in higher rates of weight/shape concerns and disordered eating behaviors, but the extent of impairment in this subset of high‐risk adolescents has not been explored. Research Methods and Procedures: Eighty‐one overweight adolescents (63% girls) presenting for an Internet‐based weight loss program were assessed at baseline using the Eating Disorder Examination Questionnaire, the Depression, Anxiety, and Stress Scale, and the Pediatric Quality of Life questionnaire. Adolescents who earned elevated scores on both the Weight Concern and Shape Concern subscales of the Eating Disorder Examination Questionnaire were considered at high risk for the development of eating disorders (56.8%). Results: Comparisons of high‐ and normal‐risk groups revealed that high‐risk adolescents reported higher levels of depression [F(3,76) = 5.75, p = 0.019], anxiety [F(3,76) = 5.67, p = 0.020], and stress [F(3,75) = 8.50, p = 0.005], and greater impairments in physical health [F(3,77) = 10.7, p = 0.002], emotional functioning [F(3,77) = 5.3, p = 0.024], and social functioning [F(3,77) = 10.0, p = 0.002]. There were no differences in school functioning [F(3,77) = 1.5, p = 0.219]. Among the high‐risk adolescents, over half (52.2%) reported binge eating at least once in the past month. Discussion: Results suggest that overweight adolescents at high risk for the development of eating disorders also experience elevated levels of negative affect, impairment in health‐related quality of life, and eating disturbances, although prospective data are needed to determine the directionality between eating disorder pathology and general psychopathology. Further research is warranted to evaluate whether behavioral weight loss interventions should be enhanced for this high‐risk subset.     

Association of major depression and binge eating disorder with weight loss in a clinical setting

Objective: Obesity has been linked to both major depressive disorder (MDD) and binge eating disorder (BED) in clinical and epidemiological studies. The present study compared weight loss among patients with and without MDD and BED who participated in a hospital‐based weight loss program modeled after the Diabetes Prevention Program. Research Methods and Procedures: Of 131 obese patients who enrolled in treatment, 17% were diagnosed with MDD only, 13% were diagnosed with BED only, 17% were diagnosed with both MDD and BED, and 53% lacked either diagnosis in a pretreatment clinical interview. Results: After treatment, patients with MDD only attained 63% of the weight loss that non‐depressed patients attained. Patients with BED only attained 55% of the weight loss that non‐binge eaters attained. The effect of MDD on weight loss was not accounted for by the presence of BED or vice versa. Only 27% of patients with both MDD and BED achieved clinically significant weight loss compared with 67% of patients who had neither disorder. Results were not significantly altered when gender, age, and diabetes status were adjusted. Conclusion: Both MDD and BED were prevalent among this obese clinical population, and each disorder was independently associated with worse outcomes. Research is needed to investigate how to increase the efficacy of behavioral weight loss programs for individuals with MDD and/or BED.     

Lipid-mediated release of GLP-1 by mouse taste buds from circumvallate papillae: putative involvement of GPR120 and impact on taste sensitivity

Glucagon-like peptide-1 (GLP-1) signaling modulates sweet-taste sensitivity in the mouse. Because circumvallate papillae (CVPs) express both GLP-1 and its receptor, a local regulation has been suggested. However, whether dietary lipids are involved in this regulation, as shown in the gut, is unknown. By using a combination of biochemical, immunohistochemical, and behavioral approaches, the present data i) confirm the role of GLP-1 signaling in the attraction for sucrose, ii) demonstrate that minute quantities of long-chain FAs (LCFAs) reinforce the attraction for sucrose in a GLP-1 receptor-dependent manner, iii) suggest an involvement of the LCFA receptor GPR120 expressed in taste buds in this system, and iv) support the existence of a regulation by GLP-1 of the lipid sensing mediated by lingual CD36. Therefore, oro-sensory detection of LCFAs may affect sweet and fatty taste responsiveness by controlling the secretion of lingual GLP-1. This regulatory loop, probably triggered by the LCFA-GPR120 interaction, might contribute to the high palatability of foods rich both in fat and sugar.     

Patient characteristics as predictors of weight loss after an obesity treatment for children

Objective: To examine pretreatment patient characteristics as predictors of treatment outcome 2 years after completion of an inpatient treatment for children with obesity. Research Methods and Procedures: Children (N = 122) ranging in age from 7 to 17 years [mean, 12.7 ± 2.3 (SD) years] with a mean adjusted BMI of 179.5 ± 28.6% participated in an inpatient obesity treatment program. Children (90.2% response rate) participated in the 2‐year follow‐up. Eight predictors, administered at baseline, were entered in separate regression analyses, with weight loss and changes on three psychological health measures as the outcome measures. Results: Analyses revealed that baseline degree of overweight, age, and initial weight loss were significant positive predictors of weight loss 2 years after treatment, whereas eating disorder characteristics were a negative predictor. Sex, socioeconomic status, global self‐esteem, and symptoms of psychopathology did not predict weight loss. With regard to the psychological outcome measures, baseline symptomatology emerged as the most important predictor of treatment changes. Discussion: Long‐lasting weight loss is associated with severity of pretreatment characteristics. Identification of the clinical markers for long‐term response to treatment is useful to set realistic weight loss goals for clients and to tailor treatment programs to patient characteristics.     

Tadpole–odonate larvae interactions: influence of body size and diel rhythm

Several studies have shown that prey and predator body size may affect the outcome of predator–prey interactions. However, few studies have taken in account the changes on predator–prey interactions over 24 h. In a tropical freshwater system I evaluated how predator and prey size, and their diel rhythm in activity influenced the interaction between Physalaemus pustulosus tadpoles and dragonfly larvae. Tadpoles of different size classes were exposed to two size classes of the dragonfly larvae Rhionaeschna spec. Feeding trials were conducted during day and night. Tadpole activity showed a diel rhythm and affected size-selective predation of the smallest dragonfly larvae, but not of the larger ones. Predator and prey size had a significant effect on the prey survivorship and prey size had a significant effect on the preference of the predator. The interaction between both factors was significant, indicating that they did not operate independently. I conclude that the predator–prey interactions between odonate larvae and anuran tadpoles were mainly affected by the size of the prey and the predator, and less by the diel activity pattern of the prey.