http://www.digitaljournal.com/tech-and-science/science/essential-science-is-anorexia-partly-caused-by-gut-bacteria/article/554410

Essential Science: Is anorexia partly caused by gut bacteria?

Posted Jul 22, 2019 by Tim Sandle
Anorexia is primarily a psychological condition and there are many underlying factors. One new factor to come to light, which may well play an influence, is with the microbiome of the human gut, according to British researchers.
Between 30 000 and 40 000 people in France suffer from anorexia  90% of them women
Between 30,000 and 40,000 people in France suffer from anorexia, 90% of them women
Joel Saget, AFP/File
The causes of anorexia nervosa are complicated. While the psychiatric nature has been well studied, researchers remain concerned that treatment success rates remain relatively low. To examine whether there are any identifiable genetic causes for this condition, researchers from King’s College, London, analysed data relating to 16,992 cases of anorexia (contrasted against 55,525 controls) drawn from 17 countries found in North America, Europe and Australasia.
Those with anorexia submitted their DNA through the Anorexia Nervosa Genetics Initiative or the eating disorders working group of the Psychiatric Genomics Consortium.
There were three interesting findings from the analysis. The first was that there is a genetic basis of anorexia nervosa and this overlaps with metabolic (including glycemic), lipid (fats) and anthropometric (body measurement) traits. The second finding is that the identified genetic basis of anorexia nervosa is also associated with other psychiatric disorders including obsessive-compulsive disorder, depression, anxiety and schizophrenia.
The third finding is that the genetic factors linked with anorexia nervosa similarly influence physical activity. This may explain why people with anorexia nervosa seek to be highly active.
In all, the scientists pinpointed eight genes that linked anorexia to anxiety, depression and obsessive compulsive disorder.
According to lead researcher Dr Gerome Breen: “Our study shows metabolic differences may also contribute to the development of the disorder. Furthermore, our analyses indicate that the metabolic factors may play nearly or just as strong a role as purely psychiatric effects.”
This key experiment shows the successful protection of a phage-sensitive bacterial strain against a ...
This key experiment shows the successful protection of a phage-sensitive bacterial strain against a virus. Top-right - bacteria growing in the absence of a virus; Top-left - holes in the culture caused by an infecting virus; Bottom - when equipped with specific CRISPR defense system components, the bacteria became resistant to the virus.
John van der Oost
Furthermore, the researchers connected this and other psychiatric illnesses to gut bacteria via the “gut-brain axis”. This refers to how the trillions of organisms that make up the gut microbiome can interact with our nervous systems via different pathways like neurotransmitter signaling. When the ideal balance of gut bacteria are disrupted, this can trigger different physiological changes.
The outcome suggests that the changing gut microbiome affects metabolism, hunger, and satiety, and researchers are continuing to examine how the balance of organisms that we are host to impact upon health and wellbeing. Greater insights here can assist with recovery programs and with selecting appropriate food types as part of the recovery process.
Implications
The new findings in relation to anorexia nervosa – that the disease should be considered to be a hybrid 'metabo-psychiatric disorder', mean that the disease may have other underlying causes, could go some way towards explaining why traditional ways used to treat the condition (like cognitive interventions or psychotherapy) are not always successful with all patients.
The data will also be of value for developing metabolism-based therapies, or for helping to spot those at risk of relapse. In other words, treatments for the disorder may need to go beyond psychotherapy, and encompass diet, focused on how to recreate a healthy gut microbiome.
Representative image of the bacterium Clostridium.
Representative image of the bacterium Clostridium.
Donna Rain
Research paper
The research has been published in the journal Nature Genetics, under the title “Genome-wide association study identifies eight risk loci and implicates metabo-psychiatric origins for anorexia nervosa.”
The effects of an inflammatory diet
In related research, scientists, brought together by the Spanish Association Against Cancer, have identified the detriments that an inflammatory diet can have on increasing the risk of certain types of breast cancer the research looks at the correlation between inflammatory and antioxidant diets in relation to the possibility of developing colorectal and breast cancer.
The research shows how a pro-inflammatory and pro-oxidant diet is a very important risk factor for colon cancer. There was, however, no significant increase in breast cancer risk. Both of these indicative findings will need to be supported by further research. The study is reported to the journal Nutrients, in a research paper headed “Dietary Inflammatory Index, Dietary Non-Enzymatic Antioxidant Capacity, and Colorectal and Breast Cancer Risk (MCC-Spain Study).”
Essential Science
This article is part of Digital Journal's regular Essential Science columns. Each week Tim Sandle explores a topical and important scientific issue. Last week we reported how scientists have discovered the biggest seaweed bloom in the world. This is a record-breaking belt of brown algae, from West Africa to the Gulf of Mexico. It’s here to stay for the long-term, and this means ecological trouble.
The week before we found out that scientists working at Google are investigating cold fusion technology, to be used as an energy source.