Low oxytocin levels are related to alexithymia in anorexia nervosa.

OBJECTIVE: Anorexia nervosa is associated with social-emotional functioning deficits and low levels of the social neurohormone oxytocin, even after weight gain. The relationship between low oxytocin levels and social-emotional functioning impairment has not been studied. METHOD: We performed a cross-sectional study of 79 women (19 who were less than 85% of ideal body weight [IBW] with anorexia nervosa [AN], 26 who were 90-120% IBW with a history of AN [AN-WR], and 34 who were 90-120% IBW with no eating disorder history [H]). We administered the Eating Disorder Examination-Questionnaire (EDE-Q), Leibowitz Social Anxiety Scale-Self Report (LSAS-SR), Dimensional Assessment of Personality Pathology-Basic Questionnaire (DAPP-BQ; suspiciousness and insecure attachment subscales), and the Toronto Alexithymia Scale (TAS-20). We also analyzed fasting serum oxytocin levels. RESULTS: Most measures of social-emotional functioning showed impairment in women with AN and AN-WR compared to H. Oxytocin levels were low in AN-WR compared to H. Across groups, low oxytocin levels were associated with difficulty identifying feelings (r = -.45, p = .008) and overall alexithymia (r = -.34, p = .0489). DISCUSSION: We speculate that low oxytocin levels may contribute to alexithymia in women with anorexia nervosa.

Color-detection thresholds in rhesus macaque monkeys and humans.

Macaque monkeys are a model of human color vision. To facilitate linking physiology in monkeys with psychophysics in humans, we directly compared color-detection thresholds in humans and rhesus monkeys. Colors were defined by an equiluminant plane of cone-opponent color space. All subjects were tested on an identical apparatus with a four-alternative forced-choice task. Targets were 2° square, centered 2° from fixation, embedded in luminance noise. Across all subjects, the change in detection thresholds from initial testing to plateau performance ("learning") was similar for +L − M (red) colors and +M − L (bluish-green) colors. But the extent of learning was higher for +S (lavender) than for −S (yellow-lime); moreover, at plateau performance, the cone contrast at the detection threshold was higher for +S than for −S. These asymmetries may reflect differences in retinal circuitry for S-ON and S-OFF. At plateau performance, the two species also had similar detection thresholds for all colors, although monkeys had shorter reaction times than humans and slightly lower thresholds for colors that modulated L/M cones. We discuss whether these observations, together with previous work showing that monkeys have lower spatial acuity than humans, could be accounted for by selective pressures driving higher chromatic sensitivity at the cost of spatial acuity amongst monkeys, specifically for the more recently evolved L − M mechanism.

Disrupted Oxytocin-Appetite Signaling in Females With Anorexia Nervosa.

CONTEXT: In healthy females, oxytocin levels decrease postmeal, corresponding to increased satiety. The postprandial response of oxytocin in females with anorexia nervosa (AN)/atypical AN is unknown. OBJECTIVES: To determine the pattern of postprandial serum oxytocin levels in females with AN/atypical AN, relationship with appetite, and effect of weight, eating behavior, and endogenous estrogen status. DESIGN: Cross-sectional. SETTING: Clinical research center. PARTICIPANTS: 67 women (36 with AN [<85% expected body weight (EBW)]; 31 with atypical AN [≥ 85% EBW)]), age 22.4 ± 0.9 (mean ± SEM) years, categorized by weight, restricting vs binge/purge behavior, and estrogen status. INTERVENTIONS: Standardized mixed meal. MAIN OUTCOME MEASUREMENTS: Blood sampling for oxytocin occurred fasting and 30, 60, and 120 minutes postmeal. Subjective appetite was assessed using visual analog scales. RESULTS: In females with AN/atypical AN, oxytocin levels decreased from fasting to 60 (P = 0.002) and 120 (P = 0.005) minutes postmeal. The decrease in oxytocin from fasting to 120 minutes was greater in females with atypical AN than AN (P = 0.027) and did not differ by restricting vs binge/purge behavior or estrogen status. Controlling for caloric intake, the decrease in oxytocin was inversely related to the decrease in hunger postmeal in females with atypical AN (P = 0.04). CONCLUSIONS: In females with AN/atypical AN, oxytocin levels decrease postmeal, as established in healthy females. Weight, but not restricting vs binge/purging nor endogenous estrogen status, affects postprandial oxytocin levels. The postprandial change in serum oxytocin levels is related to appetite in females with atypical AN only, suggesting a disconnect between oxytocin secretion and appetite in the undernourished state.

A Diet High in Processed Foods, Total Carbohydrates and Added Sugars, and Low in Vegetables and Protein Is Characteristic of Youth with Avoidant/Restrictive Food Intake Disorder.

Avoidant/restrictive food intake disorder (ARFID) is characterized in part by limited dietary variety, but dietary characteristics of this disorder have not yet been systematically studied. Our objective was to examine dietary intake defined by diet variety, macronutrient intake, and micronutrient intake in children and adolescents with full or subthreshold ARFID in comparison to healthy controls. We collected and analyzed four-day food record data for 52 participants with full or subthreshold ARFID, and 52 healthy controls, aged 9-22 years. We examined frequency of commonly reported foods by logistic regression and intake by food groups, macronutrients, and micronutrients between groups with repeated-measures ANOVA. Participants with full or subthreshold ARFID did not report any fruit or vegetable category in their top five most commonly reported food categories, whereas these food groups occupied three of the top five groups for healthy controls. Vegetable and protein intake were significantly lower in full or subthreshold ARFID compared to healthy controls. Intakes of added sugars and total carbohydrates were significantly higher in full or subthreshold ARFID compared to healthy controls. Individuals with full or subthreshold ARFID had lower intake of vitamins K and B12, consistent with limited vegetable and protein intake compared to healthy controls. Our results support the need for diet diversification as part of therapeutic interventions for ARFID to reduce risk for nutrient insufficiencies and related complications.

Endogenous Oxytocin Levels in Relation to Food Intake, Menstrual Phase, and Age in Females.

CONTEXT: Oxytocin regulates a range of physiological processes including eating behavior and oxytocin administration reduces caloric intake in males. There are few data on oxytocin and eating behavior in healthy females or on the response of endogenous oxytocin to food intake and its relationship to appetite in humans. OBJECTIVES: To determine the postprandial pattern of oxytocin levels, the relationship between oxytocin and appetite, and the impact of menstrual cycle phase and age on oxytocin levels in females. DESIGN: Cross-sectional. SETTING: Clinical research center. PARTICIPANTS: Fifty-five healthy females (age 10 to 45 years). INTERVENTIONS: A standardized mixed meal was administered. MAIN OUTCOME MEASUREMENTS: Blood sampling for oxytocin occurred at fasting and at 30, 60, and 120 minutes postmeal. Appetite was assessed using Visual Analogue Scales pre- and postmeal. RESULTS: Mean fasting oxytocin levels were 1011.2 ± 52.3 pg/mL (SEM) and decreased at 30 and 60 minutes postmeal (P = 0.001 and P = 0.003, respectively). Mean oxytocin levels decreased19.6% ± 3.0% from baseline to nadir. Oxytocin area under the curve was lower in the early to midfollicular menstrual cycle phase (P = 0.0003) and higher in younger females (P = 0.002). The percent change in oxytocin (baseline to nadir) was associated with postprandial hunger (rs = -0.291, P = 0.03) and fullness (rs = 0.345, P = 0.009). These relations remained significant after controlling for calories consumed, menstrual cycle status, and age (P = 0.023 and P = 0.0001, respectively). CONCLUSIONS: Peripheral oxytocin levels in females decrease after a mixed meal and are associated with appetite independent of menstrual phase, age, and caloric intake, suggesting that endogenous oxytocin levels may play a role in perceived hunger and satiety.

Oxytocin and Its Relationship to Body Composition, Bone Mineral Density, and Hip Geometry Across the Weight Spectrum.

Context: Oxytocin (OXT), an anorexigenic hypothalamic hormone anabolic to bone, may reflect energy availability. Basal serum OXT levels are lower in anorexia nervosa (AN, state of energy deficit) than healthy controls (HC) and negatively associated with spine bone mineral density (BMD). Reports are conflicting regarding OXT levels in overweight/obesity (OB, state of energy excess). Relationships between OXT and BMD in OB and hip geometry across the weight spectrum are unknown. Objective: To determine whether overnight serum OXT levels are (1) elevated in OB and (2) associated with body composition, BMD, and hip geometry across the weight spectrum. Design: Cross-sectional. Setting: Clinical research center. Participants: Fifty-nine women, ages 18 to 45 years: amenorrheic AN (N = 16), eumenorrheic HC (N = 24), eumenorrheic OB (N = 19). Main Outcome Measures: Serum sampled every 20 minutes from 8 pm to 8 am and pooled for integrated overnight OXT levels. Body composition, BMD, and hip structural analysis measured by dual x-ray absorptiometry. Results: OXT levels were lowest in AN, higher in HC, and highest in OB (P ≤ 0.02). There were positive associations between OXT and (1) body mass index (P = 0.0004); (2) total, visceral, and subcutaneous fat (P ≤ 0.0002); (3) spine and hip BMD Z-scores (P ≤ 0.01); and (4) favorable hip geometry, namely buckling ratio (P ≤ 0.05). In a subset analysis of HC and OB, relationships between OXT and body composition, but not bone parameters, remained significant. Conclusions: These data suggest OXT is a marker of energy availability and may be a mediator of bone density, structure, and strength. OXT pathways may provide targets for obesity and osteoporosis treatment.

Low Fasting Oxytocin Levels Are Associated With Psychopathology in Anorexia Nervosa in Partial Recovery.

OBJECTIVE: Anorexia nervosa (AN), a psychiatric disorder characterized by restriction of food intake despite severe weight loss, is associated with increased comorbid anxiety and depression. Secretion of oxytocin, an appetite-regulating neurohormone with anxiolytic and antidepressant properties, is abnormal in AN. The link between oxytocin levels and psychopathology in AN has not been well explored. METHODS: We performed a cross-sectional study of 79 women aged 18-45 years (19 AN, 26 AN in partial recovery [ANPR], and 34 healthy controls [HC]) investigating the relationship between basal oxytocin levels and disordered eating psychopathology, anxiety, and depressive symptoms. AN diagnoses were based on DSM-5 criteria. Data acquisition took place between December 2008 and March 2014. Fasting serum oxytocin levels were obtained, and the following self-report measures were used to assess psychopathology: Eating Disorder Examination Questionnaire, State-Trait Anxiety Inventory, and Beck Depression Inventory-II. RESULTS: Fasting oxytocin levels were low in ANPR compared to HC (P = .0004). In ANPR but not AN, oxytocin was negatively associated with disordered eating psychopathology (r = -0.39, P = .0496) and anxiety symptoms (state anxiety: r = -0.53, P = .006; trait anxiety: r = -0.49, P = .01). Furthermore, ANPR with significant disordered eating psychopathology, anxiety symptoms, or depressive symptoms had lower oxytocin levels compared to those with minimal or no symptoms (P = .04, .02, and .007, respectively). CONCLUSIONS: We speculate that a dysregulation of oxytocin pathways may contribute to persistent psychopathology after partial weight recovery from anorexia nervosa.