Normal-weight Bulimic Patients Research Articles

Serotonin-induced decrease of intracellular Ca2+ release in platelets of bulimic patients normalizes during treatment

Numerous symptoms related to eating disorders have been shown to be influenced by serotonergic (5-HT) functioning, with the 5-HT(2A) receptor subtype being one of the most relevant involved in the pathophysiology of bulimia nervosa (BN). In line with this, Ca(2+) mobilization as mediated by 5-HT(2) receptors in platelets was shown to serve as a peripheral model for central nervous 5-HT functioning. Here, the 5-HT-induced intracellular Ca(2+) mobilization in platelets was measured in 13 female normal weight bulimic patients (14-18 years) upon admission and at the end of inpatient treatment. Findings were compared to 21 age-matched healthy female adolescents. 5-HT-induced Ca(2+) release was significantly decreased in bulimic patients upon admission and normalized during inpatient treatment. Antidepressive medication caused a significant improvement. The data provide further evidence that altered 5-HT(2) receptor functioning is involved in the pathophysiological underpinnings in BN.

Effects of Binge Eating Behavior on Fuel Oxidation and Body Composition

Objective: To investigate energy expenditure and glucose metabolism after a standard oral glucose load (75 g) in 8 normal weight bulimic women and 8 normal weight control women and to evaluate the relative endocrine implication.Design: Serum glucose and insulin were measured both in basal conditions and after the glucose load; a basal endocrine assessment and body composition was evaluated and glucose induced thermogenesis (GIT) was calculated during 300 min following the glucose load.Results: Serum glucose levels were significantly lower in bulimics both in fasting and in post-prandial state. Insulin levels were similar in bulimic and control women before and after the glucose load. FSH, leptin and free urinary cortisol (FUC) were all within the normal ranges, but significantly lower in bulimic patients compared with controls (p < 0.001). Fat mass (FM) and Fat-free mass (FFM) were reduced in bulimic patients, even if they normalized after correction per body weight. Resting energy expenditure (REE) was similar in the two groups even after FFM normalization, while GIT was lower in bulimic patients and it was strongly related to free urinary chortisol. Glucose oxidation was higher in fasting state and post glucose load, while lipid oxidation was strongly reduced.Conclusion: An energy preservation mechanism seems to be the key element for normal-weight bulimic patients’ metabolism, consisting in leptin levels and GIT reduction, and lipid oxidation inhibition.

Stomach Capacity in Obese Individuals

Given that obesity results from food in take greater than energy needs, a fascinating question has been whether obese individuals have a larger stomach capacity. Previous studies using an intragastric balloon to assess stomach capacity showed that it was larger in both moderately and severely obese individuals (1) (2). These conclusions were made from subjective criteria based on the maximal volume that the subject tolerated as well as from more objective criteria based on intragastric pressure or compliance. New findings in this issue by Kim et al. (3), from imaging with single photon emission computed tomography (SPECT), reveal a larger antral volume in obese individuals in the fasting state as also found by Chiloiro et al. (4) in obese children. Observing the stomach with SPECT provides a way to estimate the size of the stomach in vivo. It is especially useful for observation of the antrum, the more muscular less distensible lower part of the stomach, primarily involved in churning and propulsion. A large antrum is probably needed as a conduit for a large capacity upper stomach (fundus and body). Thus, these observations of an enlarged antrum in obesity are consistent with the previous measurements showing large gastric capacity based on distension of the upper or proximal stomach. The proximal stomach, which acts primarily as a reservoir, can readily distend to accommodate food ingestion. However, imaging the size of the fasting proximal stomach probably does not tell us much about its distensible capacity. After ingestion of a small liquid meal, Kim et al. (3) found no additional differences with imaging between lean and obese subjects. However, imaging of the stomach after a 300-mL meal is not really a measure of gastric capacity, inasmuch as the stomach fills to reflect the amount ingested. The increase in the proximal stomach volume from fasting to postprandial for both the obese and non-obese groups was ∼300 mL, the volume of the meal. The smaller increase in the antral volume for both groups (∼180 mL) may reflect the overflow from gastric juice. Continued gastric secretions could explain why the gastric volume did not change much between the first and second 10 minutes after the meal, despite some gastric emptying. Figure 1 of the article by Kim et al. (3) clearly shows that ingesting even a small meal mainly distends the upper part of the stomach. To assess gastric accommodation to a meal, it might have been more informative to measure changes in gastric pressure rather than in volume. For the next part of the study, the investigators had the participants drink the same liquid meal until unbearably full. They found no differences in meal intake between the weight groups. However, as the authors note, the maximal volume ingested is an inaccurate proxy for capacity, because it does not take into account the inflow from saliva and gastric juice or the outflow due to gastric emptying. Thus, the results from previous balloon measurements showing greater gastric capacity in the obese are not contradicted. Other studies suggest that obesity may not be the key to a large gastric capacity. Indeed, gastric capacity in normal-weight bulimic patients is even larger than in obese patients (5) (6) (7). Among obese patients, those who binge eat have a larger gastric capacity than those who do not (6) (7). In both obese binge eaters and normal-weight bulimic patients, gastric capacity is correlated with test meal intake (5) (7). It would have been interesting to subdivide the subjects in the study by Kim et al. (3) into those who binge eat and those who do not. As the degree of obesity increases, the likelihood of binge eating also increases (8) and may help explain why the gastric capacity in morbidly obese individuals is so large (1). Of course, gastric restriction operations for the severely obese drastically reduce capacity and lead to substantial weight loss (9). Dieting also leads to reduced gastric capacity (10), but this has not been as effective in the long-term as surgery. Even after surgery, the pouch can enlarge over time and may be related to some weight regain (9). Inserting a chronic intragastric balloon to treat obesity also has shown only modest and transient effects (11) (12) (13) because gastric capacity seems to enlarge to compensate for the displaced volume (12). Nevertheless, there may be potential pharmacological approaches to reduce gastric compliance and capacity that could be studied by combining several techniques, including intragastric pressure/volume measurements and SPECT.

Normal bone mass in bulimic women.

The aim of this study was to examine the relationship among exercise, menstrual function, and bone mineral density (BMD) in different groups of age-matched patients with eating disorders. Dieting and eating disorder history, physical activity history, and menstrual history were assessed by clinical interview in 43 bulimic and 13 anorectic young women as well as in 17 healthy control subjects (18-29 yr). BMD was assessed by dual x-ray absorptiometry. All the anorectics but only 30% of the bulimics exercised regularly from the onset of their eating disorder (P < 0.01), mainly using aerobic dancing and running. All of the anorectics had been amenorrheic since the start of their symptoms, and 68% of the bulimics had a history of menstrual dysfunction. Within the exercise subgroups of bulimic patients, there was no significant relationship between BMD and current or previous menstrual function. Anorectic patients had lower BMD than bulimics and controls in all skeletal regions studied (P < 0.01). Bulimic patients who had exercised regularly during their illness had higher total body BMD than bulimics classified as sedentary (P < 0.01). Bulimics who had exercised regularly or intermittently since the onset of their eating disorder had higher BMD than sedentary bulimics in the lumbar vertebrae, femoral neck, and legs (P < 0.05). It appears that weight-bearing exercise can prevent or attenuate bone loss at specific skeletal sites in normal weight bulimic patients, but not in anorectics.

Prolonged P300 Latency in Eating Disorders

This study investigated event-related potential (ERP) indices of information-processing in eating disorders. ERPs during an auditory two-tone discrimination task were recorded at midline at 3 sites in 28 anorexic patients, 12 low-weight bulimic patients (body mass index (BMI) under 17.5), 12 normal-weight bulimic patients (BMI over 17.5), and 40 control subjects. The P300 latency was significantly prolonged at all sites in both bulimic groups compared with that in controls, and at frontal and central electrode sites in anorexics. In contrast, the P300 amplitude did not differ between these groups at any site. The prolonged P300 latency in eating disorders suggests a task-related slowing of perceptual decisions that reflects their cognitive impairment.

Vulnerability to substance abuse in eating disorders.

Two types of eating disorders, bulimia nervosa in normal-weight bulimic (NWB) women and restricting-type anorexia nervosa (RAN), may provide insights into permissive or protective factors contributing to psychoactive substance use disorders (PSUD) in humans. These two eating disorders, while often grouped together, are at opposite extremes for rate of PSUD. Substance abuse is common in NWB patients and their family members, but rare in RAN patients. In addition, NWB and RAN are at opposite extremes in terms of pathologic feeding style and many behavioral traits (table 1). NWB individuals are impulsive, labile, may be overly sensitive to external cues, and have poor control of eating. In contrast, persons with RAN are rigid and perfectionistic, restrict eating, and are insensitive to internal and external cues.

Binge Eating Behavior in Patients with Eating Disorders

The purpose of this study was to determine whether the objectively observed binge eating behavior of obese subjects meeting the proposed DSM-IV criteria for binge eating disorder would be similar to that observed in patients with bulimia nervosa. Non-obese patients with bulimia nervosa (BN), obese subjects with binge eating disorder (BED), obese and non-obese women without eating disorders were each instructed to binge eat single- and multiple-item meals. In the multiple-item meal, the obese subjects with BED ate significantly more (1515 kcal) than obese subjects without BED (1115 kcal), but they ate less than the normal-weight bulimic patients (2680 kcal). The non-obese controls ate amounts similar to the obese non-binge-eating-disordered group (1093 and 1115.2 kcal, respectively). In the single-item meal, consisting of ice cream, patients with BN ate significantly more than any other group (1307 kcal), while obese subjects with or without binge-eating disorder ate significantly more (762 kcal) than non-obese controls (308 kcal). This study has demonstrated that although both BN and BED are characterized by recurrent episodes of binge eating, quantitatively there appear to be differences between the eating disturbances in the two disorders. Because single- and multiple-item meals differ in external cues, these results also suggest that the obese subjects with BED may be disinhibited by external cues, while obese subjects without BED may be inhibited by external cues.

Amount of calories retained after binge eating and vomiting.

While caloric consumption during binge eating has been measured, it is not known how many of the calories are retained in the gastrointestinal tract after vomiting. In 17 normal weight bulimic patients, there appeared to be a ceiling on the number of calories retained after vomiting. That is, whether or not bulimic patients had small (mean = 1,549 kcal, SD = 505) or large (mean = 3,530 kcal, SD = 438) binges, they retained similar amounts of kilocalories (mean = 1,128, SD = 497, versus mean = 1,209, SD = 574, respectively) after vomiting.

Clinical Symptomatology and Etiological Factors in Obese and Normal-Weight Bulimic Patients: A Retrospective Case-Control Study

Clinical Symptomatology and Etiological Factors in Obese and Normal-Weight Bulimic Patients: A Retrospective Case-Control Study

Neuroendocrine responses to m-chlorophenylpiperazine and L-tryptophan in bulimia.

Preclinical and clinical evidence supports a theory of serotonin (5-hydroxytryptamine [5-HT]) dysregulation in bulimia. We therefore studied the prolactin (PRL) and cortisol responses following challenges with the postsynaptic 5-HT receptor agonist m-chlorophenylpiperazine (m-CPP), 0.5 mg/kg orally, the 5-HT precursor L-tryptophan, 100 mg/kg intravenously, and placebo in a group of 28 normal weight bulimic patients and 16 healthy controls. Patients with bulimia, regardless of the presence of major depression, had significantly blunted PRL responses following m-CPP administration compared with those in controls. In contrast, only bulimic patients with concurrent major depression had significantly blunted PRL responses following L-tryptophan administration compared with those in nondepressed bulimic patients and controls. Cortisol responses following m-CPP were not significantly different for bulimic patients vs controls, although there was a trend toward blunted cortisol responses following L-tryptophan administration in the depressed bulimic patients. These differences in neuroendocrine responses were not related to differences in age, percent of average body weight, medications, time of day, peak plasma drug levels, or baseline estradiol levels. Seasonal variations in PRL responses to both agents were identified, although covariation for season did not alter the group differences. The PRL responses following m-CPP administration were inversely correlated to baseline cortisol levels in the bulimic patients, but not in the controls, suggesting a dampening effect by hypothalamic-pituitary-adrenal axis dysfunction on postsynaptic 5-HT receptor sensitivity. The reasons for the differing hormonal responses to these two serotonergic agents may relate to differential involvement of presynaptic and postsynaptic mechanisms, 5-HT receptor subtypes, and anatomical loci of action. The blunted PRL responses to m-CPP administration suggest that postsynaptic 5-HT receptor sensitivity is altered in bulimia nervosa, and that similar alterations in 5-HT receptors at or above the level of the hypothalamus may contribute to binge eating and other behavioral symptoms.

Abnormal caloric requirements for weight maintenance in patients with anorexia and bulimia nervosa

This study tested previous findings that patients with eating disorders who attain normal weight have abnormal caloric requirements for maintaining weight. Fifty-three female patients meeting the DSM-III-R criteria for anorexia nervosa and/or bulimia nervosa were divided into four subgroups, and their daily caloric intake was measured over a weight-stable period. Patients with anorexia nervosa (restricting and bulimic subtypes) were studied 4 weeks after refeeding and weight gain, when they had attained 95% of average body weight. Patients with normal-weight bulimia (previously anorexic or never previously anorexic) were studied 1-4 weeks after admission to an inpatient unit. After weight restoration, restricting anorexic patients required significantly more calories per day to maintain weight than did bulimic anorexic patients, as measured with corrections for weight, body surface area, and fat-free mass. Previously anorexic normal-weight bulimic patients required significantly more calories per day to maintain weight than never-anorexic normal-weight bulimic patients, as measured with correction for weight but not with the other factors used to correct caloric intake. To maintain stable weight after weight restoration, restricting anorexic patients require a significantly higher caloric intake than do bulimic anorexic patients. Differences in caloric needs between normal-weight bulimic patients with and without histories of anorexia may depend on the methods used to correct caloric requirements. Body surface area may be the most precise correction factor across different subgroups of eating disorder patients. Elevated caloric requirements, when coupled with reduced food intake, may particularly contribute to relapse in anorexic patients.

Circadian patterns of cortisol, prolactin, and growth hormonal secretion during bingeing and vomiting in normal weight bulimic patients

Women who are of normal weight and have bulimia nervosa exhibit multiple neuroendocrine disturbances. We hypothesized that bingeing and vomiting behavior could be contributory because food consumption in healthy volunteers increases plasma cortisol and prolactin secretion and suppresses growth hormone secretion. Thus, we investigated the effects of bingeing and vomiting on the circadian pattern (measurements every 20 min for 24 hr) of these hormones in comparison to healthy control women eating normally. Bingeing and vomiting were associated with modest increases in cortisol and prolactin and reductions in growth hormone secretion. However, this bingeing or purging did not alter mean 24-hr pattern of cortisol and growth hormone secretion as values for bulimics were similar to controls. While mean daytime patterns of prolactin secretion were similar in bulimics and controls, bulimic patients had a significant reduction of nocturnal prolactin levels. In summary, bingeing and vomiting does not appear to have a substantial influence on hormonal secretion. However, bulimic women have blunted nocturnal prolactin patterns.

Altered Cerebrospinal Fluid Neuropeptide Y and Peptide YY Immunoreactivity in Anorexia and Bulimia Nervosa

The related central nervous system peptides neuropeptide Y and peptide YY have been found to be among the most potent endogenous stimulants of feeding behavior. We measured these neuropeptides in cerebrospinal fluid to determine whether they contributed to the pathophysiologic characteristics of anorexia and bulimia nervosa. Cerebrospinal fluid neuropeptide Y concentrations were significantly elevated in underweight anorectic patients and in many of the anorectic patients studied at intervals after weight restoration. These levels normalized in long-term weight-restored anorectic patients who had a return of normal menstrual cycles. Increased neuropeptide Y activity may contribute to several characteristic disturbances in anorexia, including menstrual dysregulation. Cerebrospinal fluid peptide YY concentrations were significantly elevated in normal-weight bulimic patients abstinent from pathological eating behavior for a month compared with themselves when actively bingeing and vomiting or compared with healthy volunteers. Increased peptide YY activity may contribute to a drive to overfeed in normal-weight bulimic patients.

CSF monoamine levels in normal-weight bulimia: evidence for abnormal noradrenergic activity

Normal-weight bulimic patients have disturbed appetite, mood, and neuroendocrine function and often respond to antidepressants. Since these findings suggest abnormalities in brain monoaminergic pathways, the authors measured CSF monoamine concentrations in 27 normal-weight bulimic patients and 14 volunteers. Bulimic patients had a significantly lower mean CSF norepinephrine concentration. Levels of CSF 5-HIAA, the major serotonin metabolite, and CSF HVA, the major dopamine metabolite, were normal, although more frequent binge-eating in bulimic subjects was associated with a significantly lower CSF HVA level. Whether trait- or state-related, monoaminergic disturbances are part of this disorder's neurobiological syndrome. The lower CSF norepinephrine concentration suggests bulimia is not simply a variant of affective disorders.

Disturbances of noradrenergic systems in normal weight bulimia: Relationship to diet and menses

Several lines of evidence suggest that noradrenergic (NE) disturbances occur in normal-weight bulimic patients. The purpose of this study was to investigate factors that may be related to noradrenergic disturbances. First, we measured plasma NE during bingeing and vomiting. We found that this behavior activated the sympathetic nervous system. Bingeing produced a significant increase in the duration and the peak increase of plasma NE when compared with normal controls eating a large meal. Second, we assessed basal peripheral and central NE levels near in time (within several days of hospital admission) to chronic bingeing and vomiting. At this time, bulimics had normal basal plasma and CSF NE levels. Finally, we restudied the same patients after 30 days of inpacient hospitalization and observed abstinence from bingeing and vomiting. In this last state, bulimics had a reduction of basal plasma and cerebrospinal fluid (CSF) NE levels compared with themselves on admission and compared with healthy controls. This study confirms that reduced noradrenergic activity occurs in normal-weight bulimic women and suggests that this abnormality may emerge during abstinence from bingeing. We hypothesize that dietary intake is related to noradrenergic activity, but cause and effect remain uncertain. Noradrenergic disturbances did not appear to be related to weight, depression, physical activity, or amino acid precursors. Lower CSF NE levels were found in amenorrheic bulimic women in both states, suggesting that a noradrenergic disturbance may be associated with the frequent incidence of amenorrhea in bulimic women.

A comparison of psychological and depressive symptoms among restricting anorexic, bulimic anorexic, and normal-weight bulimic patients

Nineteen restricting anorexic, 23 bulimic anorexic, and 72 normal-weight bulimic inpatients were compared on eating disorder symptoms and related psychological and depressive symptomatology

The significance of subgroups of bulimia and anorexia nervosa: Lifetime frequency of psychiatric disorders

By a standardized interview DSM-III lifetime diagnoses were assessed in 91 eating disorders patients who were divided in four subgroups. Anorectic patients with bulimic symptoms and normal-weight bulimic patients with and without a history of anorexia nervosa had a similar history of additional psychiatric diagnoses. In general, restricting anorexics showed lower lifetime rates of psychiatric disorders than patients with bulimic symptomatology. Minor affective disorders, however, were equally distributed across all four groups.

Taste and eating disorders

Taste responses to sucrose and fat-containing stimuli were examined in a population of young women with eating disorders. Anorectic-restrictor and anorectic-bulimic patients were compared with normal-weight bulimic patients and with normal-weight control subjects. Sensory estimates of sweetness and fat content of 20 different mixtures of milk, cream, and sugar did not differ among subject groups. In contrast, relative preferences for sugar vs fat as determined by the Response Surface Method differed between patients with eating disorders and control subjects. Normal-weight bulimic patients preferred sweeter stimuli than did control subjects. Anorectic-restrictor and anorectic-bulimic patients liked sweet but disliked high-fat stimuli and showed elevated optimal sugar:fat (S:F) ratios. This pattern of response did not change following weight regain. The stability of preference profiles suggests that taste responsiveness may be independent of diagnostic categories, bulimic behaviors, or acute changes in body weight.

Comparison of lactate-induced anxiety in bulimic patients and healthy controls

Clinical symptomatology and diagnostic interview studies suggest that patients with bulimic disorder have some characteristics in common with patients with generalized anxiety disorder or panic disorder. The purpose of this study was to compare sodium lactate-induced physiological responses and anxiety symptoms in hospitalized normal weight bulimic patients and healthy controls. Bulimic patients had significantly elevated anxiety ratings at baseline, and showed a trend toward greater increases in anxiety ratings after lactate administration. Lactate-induced anxiety did not provoke an urge to binge in the bulimic patients. In keeping with the specificity of lactate-induced panic attacks in panic disorder, none of the bulimic subjects experienced a panic attack during lactate infusion.

Short-term course of depressive symptoms in patients with eating disorders.

After inpatient treatment focused on aberrant eating behavior, six depressed normal-weight bulimic patients showed little improvement in depressive or eating symptoms. Four depressed anorexic patients with bulimic behavior improved in both areas, and five restricting anorexic patients had an intermediate response.