Mar 06

Should the gut microbiota be a target for treatment in people with anorexia?


The gut microbiota consists of a community of microorganisms that live in our digestive tracts. Interest in gut microbiota has increased dramatically over the last decade as these microorganisms have many physiological roles in our body. Microbiota are important for digestion, have an important role in our immune response, and can produce several hormones and neurotransmitters (just to name a few).

It is increasingly acknowledged that microbiota can have a significant influence on the brain and its disturbance has been linked to several neurological conditions. In relation to mental health disorders, there is growing evidence that the composition of the gut microbiota is different in people with depression and anxiety compared to healthy individuals. The gut microbiota also seems to have an influence on appetite and weight regulation.

Research into the relationship between gut microbiota and eating disorders is limited although there is increasing research to suggest it is something that we should consider. There are several studies confirming that restrictive dieting, starvation, and food elimination can change the gut microbiome. For example, ketogenic diets (i.e., low-carbohydrate, high-fat diets), gluten-free diets, and low FODMAP diets (i.e, diets low in short-chain fermentable carbohydrates) can change the composition of the gut microbiome [1]. Moreover, starvation has a substantial impact on the gut microbiome. There is also evidence to suggest differences in gut microbiota in people with anorexia.  For example, in one study intestinal microbiota in people with anorexia was significantly affected at every taxonomic level, as demonstrated by a significant increase of Enterobacteriaceae, Methanobrevibacter smithii and reduction in Roseburia, Ruminococcus and Clostridium [2]. Lower microbiome diversity has also been observed in people with anorexia [3,4]

Although there have not yet been any studies examining the therapeutic effects of manipulating the gut microbiota in people with anorexia, there are strong theoretical grounds to suggest further research should be conducted. Probiotics have been demonstrated in several studies to have antidepressant and anti-stress effects and can be a beneficial treatment for people with depression and anxiety [5]. Research into the potential of probiotics in people with anorexia is essential as current treatments for anorexia are limited in their efficacy. Alternatively, a more effective treatment option would be to develop personalised treatments based on someone’s unique gut microbiota. This means completing a stool test to examine a person’s bacterial composition and then developing a treatment plan comprising dietary, prebiotic, and probiotic supplementation to help restore balance in a persons’ microbiota composition. By restoring a ‘healthy’ microbiota, improvements in mood-regulating hormones and neurotransmitters may lead to improvements in mood, cognition, and general health.

Potentially but treating the gut microbiome, providing psychological therapy, and gradually restoring someone’s diet we may see better outcomes in people with anorexia (and other eating disorders). This is an area I would be interested in researching. We just need someone to fund such a study!

References

  1. Reddel S, et al. The Impact of Low-FODMAPs, Gluten-Free, and Ketogenic Diets on Gut Microbiota Modulation in Pathological Conditions. Nutrients. 2019 Feb 12;11(2). pii: E373. link to article
  2. Herpertz-Dahlmann B, et al. Food matters: how the microbiome and gut-brain interaction might impact the development and course of anorexia nervosa. Eur Child Adolesc Psychiatry. 2017 Sep;26(9):1031-1041. link to article
  3. Kleiman, S.C. The Intestinal Microbiota in Acute Anorexia Nervosa and during Renourishment: Relationship to Depression. Anxiety, and Eating Disorder Psychopathology. Psychosom. Med. 2015, 77, 969–981.
    link to article
  4. Hanachi, M, et al. Negative role of malnutrition in cell-mediated immune response: Pneumocystis jirovecii pneumonia (PCP) in a severely malnourished, HIV-negative patient with anorexia nervosa. Clin. Nutr. ESPEN 2018, 25, 163–165. link to article
  5. Wallace, C.J.K, & Milev, R. The effects of probiotics on depressive symptoms in humans: a systematic review. Ann Gen Psychiatry. 2017; 16: 14. link to article
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