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Microbiota in anorexia nervosa: potential for treatment
- Linda Landini, Prince Dadson, Fabrizio Gallo, Miikka-Juhani Honka, Hellas Cena
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- Journal:
- Nutrition Research Reviews / Volume 36 / Issue 2 / December 2023
- Published online by Cambridge University Press:
- 25 July 2022, pp. 372-391
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Anorexia nervosa (AN) is characterised by the restriction of energy intake in relation to energy needs and a significantly lowered body weight than normally expected, coupled with an intense fear of gaining weight. Treatment of AN is currently based on psychological and refeeding approaches, but their efficacy remains limited since 40% of patients after 10 years of medical care still present symptoms of AN. The intestine hosts a large community of microorganisms, called the “microbiota”, which live in symbiosis with the human host. The gut microbiota of a healthy human is dominated by bacteria from two phyla: Firmicutes and, majorly, Bacteroidetes. However, the proportion in their representation differs on an individual basis and depends on many external factors including medical treatment, geographical location and hereditary, immunological and lifestyle factors. Drastic changes in dietary intake may profoundly impact the composition of the gut microbiota, and the resulting dysbiosis may play a part in the onset and/or maintenance of comorbidities associated with AN, such as gastrointestinal disorders, anxiety and depression, as well as appetite dysregulation. Furthermore, studies have reported the presence of atypical intestinal microbial composition in patients with AN compared with healthy normal-weight controls. This review addresses the current knowledge about the role of the gut microbiota in the pathogenesis and treatment of AN. The review also focuses on the bidirectional interaction between the gastrointestinal tract and the central nervous system (microbiota–gut–brain axis), considering the potential use of the gut microbiota manipulation in the prevention and treatment of AN.
Effects of popular diets on anthropometric and metabolic parameters: an umbrella review of meta-analyses of randomized controlled trials
- Monica Dinu, Giuditta Pagliai, Donato Angelino, Alice Rosi, Margherita Dall'Asta, Letizia Bresciani, Cinzia Ferraris, Monica Guglielmetti, Justyna Godos, Cristian Del Bò, Daniele Nucci, Erika Meroni, Linda Landini, Daniela Martini, Francesco Sofi
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- Journal:
- Proceedings of the Nutrition Society / Volume 79 / Issue OCE2 / 2020
- Published online by Cambridge University Press:
- 10 June 2020, E672
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Introduction:
The prevalence of overweight, obesity, and their related complications is increasing worldwide. We aimed to summarise and critically evaluate the effects of different popular diets on anthropometric parameters and metabolic risk factors.
Material and methods:An umbrella review of meta-analyses of randomized controlled trials was conducted according to the Joanna Briggs Institute Umbrella Review Methodology. The review protocol has been registered on PROSPERO (ID: CRD42019126103). Medline, Embase, Scopus, Cochrane Database of Systematic Reviews, and Web of Science were searched from inception to April 2019 to identify meta-analyses of randomized controlled trials that examined the effects of different diets on anthropometric parameters and metabolic risk factors. For each association, we estimated the summary effect size by random-effects and fixed-effects models, the 95% confidence interval, and the 95% prediction interval. We also assessed the between-study heterogeneity and evidence for small-study effects. We further applied standardized methodological criteria to evaluate the epidemiological credibility of the statistically significant associations.
Results:Overall, 80 articles reporting 495 unique meta-analyses were examined, covering a wide range of popular diets: low-carbohydrate (n = 21 articles), high-protein (n = 8), low-fat (n = 9), palaeolithic (n = 2), low glycaemic index/load (n = 12), intermittent energy restriction (n = 6), Mediterranean (n = 11), Nordic (n = 2), vegetarian (n = 9), Dietary Approaches to Stop Hypertension or DASH (n = 6), and portfolio dietary pattern (n = 1). The methodological quality of most articles (n = 65; 81%), evaluated using the AMSTAR-2 questionnaire, was low or critically low. The strength of evidence was generally weak. The most consistent evidence was reported for Mediterranean diet, with suggestive evidence of an improvement in weight, body mass index (BMI), total cholesterol, glucose and blood pressure. Suggestive evidence of an improvement in weight and blood pressure was also reported for DASH diet. Low-carbohydrate, high-protein, low-fat and low-glycaemic index/load diets showed suggestive and/or weak evidence of a reduction in weight and BMI, but contrasting evidence for lipid, glycaemic and blood pressure parameters, suggesting potential risks of unfavourable effects. Finally, evidence for palaeolithic, intermittent energy restriction, Nordic, vegetarian and portfolio dietary patterns was graded as weak or not statistically significant.
Discussion:Most meta-analyses showed low methodological quality and the strength of evidence, assessed using evidence classification criteria, was generally weak. Among all the diets evaluated, Mediterranean diet had the strongest and most consistent evidence of a positive effect on both anthropometric parameters and metabolic risk factors.