Macronutrient intake associated with weight gain in adolescent girls with anorexia nervosa

Gut microbiome-brain interactions in anorexia nervosa: Potential mechanisms and regulatory strategies

Anorexia nervosa (AN) is a psychiatric disorder characterised by malnutrition, fear of weight gain, and body image disturbances. The aetiology of AN is complex, and may involve environmental factors, genetic factors, and biochemical factors, with the latter meaning that AN may be closely associated with neurons, neurotransmitters, and hormones related to appetite and emotional regulation. In addition, an increasing number of studies have shown there is a link between the intestinal microbiota and psychiatric disorders, such as depression. However, few studies and reviews have focused on AN and gut microbes. Accordingly, in this review, we examine the potential pathogenesis of AN in terms of changes in the gut microbiota and its metabolites, and their effects on AN. The neurobiological function of the nervous system in relation to AN are also been mentioned. Furthermore, we suggest future research directions for this field, and note that probiotics may be developed for use as dietary supplements to help alleviate AN in patients.

Macronutrient intake: Hormonal controls, pathological states, and methodological considerations

A plethora of studies to date has examined the roles of feeding-related peptides in the control of food intake. However, the influence of these peptides on the intake of particular macronutrient constituents of food - carbohydrate, fat, and protein - has not been as extensively addressed in the literature. Here, the roles of several feeding-related peptides in controlling macronutrient intake are reviewed. Next, the relationship between macronutrient intake and diseases including diabetes mellitus, obesity, and eating disorders are examined. Finally, some key considerations in macronutrient intake research are discussed. We hope that this review will shed light onto this underappreciated topic in ingestive behavior research and will help to guide further scientific investigation in this area.

Restrained eating behaviour, anorexia nervosa and food consumption between children and adolescents: a scoping review

Anorexia nervosa (AN) and restrained eating behaviour (REB) are characterised by reduced food intake to achieve body weight loss. This scope review aimed to describe the existing evidence on the association between AN, restrictive eating behaviour and food consumption. Studies with children and adolescents of both sexes of all races and ethnicities were included. Experimental and observational studies, systematic reviews, meta-analysis, case reports or series, conference abstracts, dissertations and theses were also included. The search was conducted in ten electronic databases and grey literature without language restriction on 14 November 2020. Twenty-four studies met the inclusion criteria. Most studies included girls and identified lower intake of energy content, fat and certain micronutrients. There was also a higher intake of caffeine, fibre, vegetables, legumes and fruits and a lower intake of low-quality snack, fast food, sweets and foods with high carbohydrate and fat contents. The need to improve the quality of the diet among study participants was also identified. Thus, it is recommended that the evaluation of food consumption be careful to develop effective prevention strategies for the development of AN/REB and minimise nutritional deficiencies in these individuals.

Nutrient Intake and Dietary Inflammatory Potential in Current and Recovered Anorexia Nervosa

Anorexia nervosa (AN) is characterised by disrupted and restrictive eating patterns. Recent investigations and meta-analyses have found altered concentrations of inflammatory markers in people with current AN. We aimed to assess nutrient intake in participants with current or recovered AN, as compared to healthy individuals, and explore group differences in dietary inflammatory potential as a possible explanation for the observed alterations in inflammatory markers. We recruited participants with current AN (n = 51), those recovered from AN (n = 23), and healthy controls (n = 49). We used the Food Frequency Questionnaire (FFQ), to calculate a Dietary Inflammatory Index (DII^®) score and collected blood samples to measure serum concentrations of inflammatory markers. In current AN participants, we found lower intake of cholesterol, compared to HCs, and lower consumption of zinc and protein, compared to HC and recovered AN participants. A one-way ANOVA revealed no significant group differences in DII score. Multivariable regression analyses showed that DII scores were significantly associated with tumour necrosis factor (TNF)-α concentrations in our current AN sample. Our findings on nutrient intake are partially consistent with previous research. The lack of group differences in DII score, perhaps suggests that diet is not a key contributor to altered inflammatory marker concentrations in current and recovered AN. Future research would benefit from including larger samples and using multiple 24-h dietary recalls to assess dietary intake.

Anorexia Nervosa-What Has Changed in the State of Knowledge about Nutritional Rehabilitation for Patients over the Past 10 Years? A Review of Literature

Anorexia nervosa (AN) is a psycho-metabolic disorder with a high risk of somatic complications such as refeeding syndrome (RFS) and carries the highest mortality rate of all psychiatric illnesses. To date, the consensus on the care for patients with AN has been based on recommendations for a combination of alimentation and psychotherapy. It is important to establish an initial caloric intake that will provide weight gain and minimize the risk of complications in the treatment of undernourished patients. Research over the past few years suggests that current treatment recommendations may be too stringent and should be updated. The aim of this paper is to systematize the current reports on nutritional rehabilitation in AN, to present the results of studies on the safe supplementation of patients and its potential impact on improving prognosis and the healing process. This review of literature, from 2011-2021, describes the changing trend in the nutritional protocols used and the research on their efficacy, safety, and long-term effects. In addition, it presents previous reports on the potential benefits of introducing vitamin, pro-and prebiotic and fatty acid supplementation.

Macro- and Micronutrient Intake in Children with Avoidant/Restrictive Food Intake Disorder

Although case studies in avoidant/restrictive food intake disorder (ARFID) indicate severe nutritional deficiencies in those with a highly limited amount or variety of food intake, systematic analyses on food intake in treatment-seeking children and adolescents with ARFID are lacking. Within this study, n = 20 patients with an interview-based diagnosis of ARFID (0–17 years) were included and compared to n = 20 healthy controls individually matched for age and sex. Children or parents completed three-day food diaries and a food list. Macronutrient, vitamin, and mineral supply was determined based on the percentage of their recommended intake. The results showed a significantly lower total energy and protein intake in ARFID versus controls, with trends for lower fat and carbohydrate intake. ARFID subtypes of limited amount versus variety of food intake significantly differed in macro-, but not micronutrient intake. Those with ARFID met only 20–30% of the recommended intake for most vitamins and minerals, with significantly lower intake relative to controls for vitamin B1, B2, C, K, zinc, iron, and potassium. Variety of food intake was significantly reduced in ARFID versus controls in all food groups except carbohydrates. This study demonstrated that ARFID goes along with reduced everyday life macro- and micronutrient intake, which may increase the risk for developmental and health problems. Future studies additionally assessing serum nutrient levels in a larger sample may further explore differences in food intake across diverse ARFID presentations.

The effect of repetitive transcranial magnetic stimulation on food choice-related self-control in patients with severe, enduring anorexia nervosa

OBJECTIVE

Individuals with anorexia nervosa (AN) pursue low-fat, low-calorie diets even when in a state of emaciation. These maladaptive food choices may involve fronto-limbic circuitry associated with cognitive control, habit, and reward. We assessed whether high-frequency repetitive transcranial magnetic stimulation (rTMS) to the left dorsolateral prefrontal cortex (DLPFC) influenced food-related choice behavior in patients with severe, enduring (SE)-AN.

METHOD

Thirty-four females with SE-AN completed a Food Choice Task before and after 20 sessions of real or sham rTMS treatment and at a 4-month follow-up. During the task, participants rated high- and low-fat food items for healthiness and tastiness and then made a series of choices between a neutral-rated food and high- and low-fat foods. Outcomes included the proportion of high-fat and self-controlled choices made. A comparison group of 30 healthy women completed the task at baseline only.

RESULTS

Baseline data were consistent with previous findings: relative to healthy controls, SE-AN participants showed a preference for low-fat foods and exercised self-control on a greater proportion of trials. There was no significant effect of rTMS treatment nor time on food choices related to fat content. However, among SE-AN participants who received real rTMS, there was a decrease in self-controlled food choices at post-treatment, relative to baseline. Specifically, there was an increase in the selection of tasty-unhealthy foods.

DISCUSSION

In SE-AN, rTMS may promote more flexibility in relation to food choice. This may result from neuroplastic changes in the DLPFC and/or in associated brain areas.

Bone accrual in oligo-amenorrheic athletes, eumenorrheic athletes and non-athletes

BACKGROUND

Mechanical loading improves bone mineral density (BMD) and strength while decreasing fracture risk. Cross-sectional studies show that exercise advantage is lost in oligo-amenorrheic athletes (OA). Longitudinal studies examining the opposing effects of exercise and hypogonadism on bone are lacking in adolescents/young adults.

OBJECTIVE

Evaluate differences in bone accrual over 12 months in OA, eumenorrheic athletes (EA) and non-athletes (NA). We hypothesized that bone accrual would be lower in OA than EA and NA, with differences most pronounced at non-weight bearing trabecular sites.

METHODS

27 OA, 29 EA, and 22 NA, 14-25 years old, completed 12-months of the prospective study. Athletes were weight-bearing endurance athletes. Subjects were assessed for areal BMD and bone mineral content (BMC) using DXA at the femoral neck, total hip, lumbar spine and whole body (WB). Failure load (a strength estimate) at the distal radius and tibia was assessed using microfinite element analysis of data obtained via high resolution peripheral quantitative computed tomography (HRpQCT). The primary analysis was a comparison of changes in areal BMD, BMC, and failure load across groups over 12-months at the respective sites.

RESULTS

Groups did not differ for baseline age, height or BMI. Percent body fat was lower in both OA and EA compared to NA. OA attained menarche later than EA and NA. Over the follow-up period, OA gained 1.9 ± 2.7 kg of weight compared to 0.5 ± 2.4 kg and 0.8 ± 2.3 kg in EA and NA respectively (p = 0.09); 39% of OA resumed menses. Changes in BMD, BMD Z-scores, and tibial failure load over 12-months did not differ among groups. At follow up, EA had higher femoral neck, hip and WB BMD Z-scores than NA, and higher hip BMD Z-scores than OA (p < 0.05) after adjusting for covariates. At follow-up, radial failure load was lower in OA vs. NA, and tibial failure load lower in OA and NA vs. EA (p ≤ 0.04 for all). Change in weight and fat mass were associated with changes in BMD measures at multiple sites.

CONCLUSION

Despite weight gain and menses recovery in many OA during follow-up, residual deficits persist without catch-up raising concerns for suboptimal peak bone mass acquisition.

The gut microbiome in anorexia nervosa: relevance for nutritional rehabilitation

Rapidly accumulating evidence supports the important role of gut microbiome in the regulation of mood, behaviour, appetite, gastrointestinal symptomology, and nutrient metabolism. These are all core features frequently altered in individuals with anorexia nervosa (AN). Current treatment recommendations for AN support the use of high-calorie diets as an essential part of nutritional rehabilitation, commonly achieved by elevating the fat content of the diet. However, in contrast to this approach, there is accumulating evidence suggesting the importance of balanced, high-fibre diets on the gut microbiome. Studies have demonstrated profound differences in the microbial composition of underweight people with AN and those of normal- or overweight individuals. Specific alterations vary widely between studies. It is thus far unclear to what extent the observed differences are brought on by iatrogenic effects of nutritional rehabilitation or the disorder itself. To date, only two studies have investigated the changes in the intestinal microbiota during nutritional rehabilitation and corresponding weight restoration. These studies suggest that the gut microbiome of AN patients was different to healthy controls both prior and following nutritional rehabilitation, though it is noted that these states were associated with lower and higher nutritional intakes, respectively. There is a clear need for further investigation regarding the effects of nutritional rehabilitation on the gut microbiome. Such research would provide insights into the potential role of gut microbiome in modulating the pathophysiology of AN and inform future treatment strategies.