Researchers' Zone:

Bacteria from a healthy donor’s bowels have been used for the first time to help an anorexia patient gain weight. This is a pilot study involving only one participant, so the method needs further testing.

Slime-loving bacteria from fresh faeces may be able to help anorexia patients

Researchers have transferred fresh faeces from a healthy donor and helped one anorexia patient gain weight. It is the first time it has been done. Now it requires further testing to show that the weight gain was not just a lucky coincidence.

Transferring faeces from one human being to another may sound unpleasant, but this cheap method has shown that it can actually save lives.

So far, the method is only used in hospitals to fight life-threatening intestinal infections, but there is a strong interest in using the method to alleviate other diseases.

Anorexia is a life-threatening eating disorder characterised by a distorted body image, phobia of weight gain and restrictive eating, leading to sufferers being severely underweight with physical and mental diseases as complications.

Weight gain with the help of donated faeces

Helping patients gain weight is important because it hinders relapses and improves the patients’ overall prognosis. However, effective strategies are needed to help the patient avoid relapses, even after the patient attempts to maintain a normal diet.

Many patients experience difficulties both in regaining a normal body weight and in continuing a normal intake of food.

Currently, there is reason for optimism in that regard. Swedish and Dutch researchers have, for the first time, helped an anorexia patient gain weight by transferring fresh faeces from a healthy donor.

However, it is worth emphasising that it is merely a one-patient pilot study, which is why more substantial research is needed before we can know for sure that it is working.

Bowel bacteria influence weight

The bacteria we carry around in our bowels – also called the intestinal microbiome – are currently undergoing intense studies in relation to a whole range of diseases, and they have been recognised as an important regulator of body weight in humans and animals.

The transfer of fresh faeces in research and medicine from a healthy donor to patients, also known as faecal matter transplantation (FMT), has proven to be able to cure life-threatening infections and may possibly lead to increased weight in both humans and animals despite an unaltered intake of calories.

In the very latest research, this knowledge of the intestinal microbiota has been used for the first time to help one patient with anorexia gain weight.

This is how researchers performed a fecal transplant to an anorexic patient:

  • Two years earlier, the patient had been diagnosed with anorexia but had now become stable and resumed a normal diet that was high in calories (2,500 calories per day). Even so, she was still struggling to gain weight and permanently weighed around 45-46 kilos.
  • The 26-year-old woman with anorexia volunteered and had a once off faecal transfer from a healthy donor who was not related to her.
  • In practical terms, this was done by the faeces being introduced via the mouth through a tube that passed through the stomach and into the upper part of the small intestine.

Few side effects and very high recovery rates

The method might sound unpleasant, and it can be hard to understand why anyone would even volunteer for such treatment. But knowledge from this type of treatment (FMT) associated with intestinal infections shows very few side effects, very high recovery rates, and that patients were very willing to try it.

Other studies have shown that it will be possible in future to receive the treatment in the form of a pill rather than having faeces introduced via a tube through one end or the other.

After her FMT treatment, the patient was followed closely for 36 weeks. By the 36-week follow-up, she had gained 13.8 percent (6.3 kilos) in weight and had 55 percent more body fat – despite a self-reported stable diet with the same intake of calories as before.

No side effects were reported from the treatment.

Bacteria metabolise other elements of the diet

The explanation of the increased body weight with an unaltered diet may be that some bacteria are better at breaking down parts of the diet than we are ourselves.

The bacteria can form short-chained fatty acids from parts of the diet, such as dietary fibres, that would otherwise exit the body untouched.

These fatty acids are full of energy that our intestines can absorb, thereby leading to more calories from the same diet – depending on what kind of bacteria we have in our intestinal microbiome.

Slime-loving bacteria

Even though the patient's intestinal microbiome slowly came to resemble the intestinal microbiome she had had before the treatment, the researchers found that the presence of one bacterium in particular was significantly increased, namely a bacterium called Akkermansia (full name: Akkermansia muciniphila).

This bacterium is a slime-loving bacterium that can live on mucus from the intestinal wall, but it can also produce the short-chained fatty acids. It breaks down the mucin in the mucus but also signals to the person's intestine so that it produces more mucus.

This is beneficial for Akkermansia itself, which then has more to eat, but perhaps it also benefits the person, as the mucus layer protects the intestines from inflammatory conditions seen in cases of obesity, type 2 diabetes and irritable bowel syndrome.

Cause or just context?

It is important to note that this research is based on one patient alone, a so-called case-story.

It is possible that the weight gain is just a coincidence and that the fresh faeces treatment in itself did not improve anything.

Therefore, the researchers also emphasise that more research and larger scale trials with humans – both with faeces transplants and placebo treatments – are needed in order to determine whether the treatment can be used in the fight against anorexia in the future.

In other words, we cannot know yet whether this is the way forward in relation to anorexia treatments. But it lays the basis for further research to examine the possibilities involved with bowel bacteria transplantation.

Translated by Stuart Pethick, translation services. Read this version in Danish at’s Forskerzonen.


Kenneth Klingenberg Barfod's profile (KU)

Magnus Sjøgren's profile (KU)

"Weight Gain after Fecal Microbiota Transplantation in a Patient with Recurrent Underweight following Clinical Recovery from Anorexia Nervosa", Psychother Psychosom (2019) DOI: 10.1159/000495044

"Fecal microbiota transplantation: donor relation, fresh or frozen, delivery methods, cost-effectiveness", Annals of Gastroenterol (2019) DOI: 10.20524/aog.2018.0328

"Weight gain after fecal microbiota transplantation", Open Forum Infect Dis. (2015) DOI: 10.1093/ofid/ofv004.

"Gut microbiota from twins discordant for obesity modulate metabolism in mice", Science (2013) DOI: 10.1126/science.1241214.

“Dysbiosis of the Microbiota in Anorexia Nervosa: Pathophysiological Implications”, (intecOpen) by Magnus Sjögren, Stein Frostad and Kenneth Klingenberg Barfod.

Powered by Labrador CMS