select search filters
briefings
roundups & rapid reactions
Fiona fox's blog
A randomised controlled trial published in Nature Medicine looks at pasteurized Akkermansia muciniphila MucT for weight loss maintenance in people with overweight and obesity.
Prof Kieran Tuohy, Professor of Energy Metabolism and Microbiome, University of Leeds, said:
Does the press release accurately reflect the science?
“Yes, the press release gives a fair interpretation of the research article Mount et al.”
Is this good quality research? Are the conclusions backed up by solid data?
“The study used the randomised controlled trial design, a gold standard in determining cause and effect between ingestion of a test food and an observed health effect. It clearly showed that consuming the pasteurised Akkermansia muciniphilaMucT capsules helped people who had already lost weight following a low-calorie diet for 8 weeks to keep more of the weight off than people taking a control or placebo capsule. This an amazing observation, and an important one given the difficulties people face maintaining body weight after either dieting or successful treatment with GLP-1 RA medications. Indeed, this study strongly suggests that gut health and the interaction between gut bacteria, even dead ones in this case, and the human body is important for maintaining body weight. It raises interesting research questions and possibilities for helping people who have lost body weight after treatment with GLP-1 RA drugs since these people seem to put weight back on quickly once they stop taking these hormonal drugs. The study also observed that the Akk. muciniphila MucT treatment also improved insulin sensitivity and increased energy content of the faeces. These observations give some interesting hints at possible mechanisms of action and are in line with evidence form previous human studies and from mouse experiments but showing how Akk. muciniphila MucT works will need further, mechanistic human studies and over a longer period of time.”
How does this work fit with the existing evidence around Akkermansia muciniphilaMucT supplementation?
“As noted by the authors, a previous study in people with the metabolic syndrome, a condition that leads to type 2 diabetes, showed improvements in metabolic and heart disease risk factors. Similarly, this research group and others have shown that Akk. muciniphila and specifically, a protein (Amuc_1100) on its surface, can reduce inflammation and improve metabolic health markers, including GLP-1, in mouse experiments. Of course, this bacterial surface protein does not need Akk. muciniphila MucT to be alive to have an effect on the host immune system. Although little difference in immune parameters or hormones that regulate hunger and energy intake like GLP-1 were observed in this human study, changes in these parameters may need differently designed human studies. When and where we measure these things can determine whether we can observe changes in response to intake of a test food or drug, for example, how long after ingestion blood samples were collected or whether markers of inflammation were measured in blood or fat tissue may effect our ability to observe changes. Therefore, as highlighted by the authors, further mechanistic studies in humans are needed to uncover how this all works.”
Have the authors accounted for confounders? Are there important limitations to be aware of?
“By in large yes. The did mention that a better placebo might have provided a stronger confidence in the effect they observed, but in fairness, this is a minor point. The study was only for a fairly short period of time, but the authors too mentioned this as a weakness in their current study. “
What are the implications in the real world? Is there any overspeculation?
“As mentioned above, this study has implications for how we design dietary strategies to help people who have lost weight after dieting, or increasingly, after successful treatment with GLP-1 RA medications to keep the weight off and prevent the return of poor regulation of blood glucose, a main driver of type 2 diabetes onset. It shows that what happens in the gut does not just stay in the gut but has implications for whole body energy metabolism and disease risk and supports further studies targeting how our gut bacteria interact with our bodies to help in the fight against obesity and the diseases of obesity. “
Comments from our friends at the Spanish SMC:
Francisco Jesús Gómez Delgado, coordinator of the Vascular Risk Unit and head of the Department of Internal Medicine at Jaén University Hospital, associate professor of Medicine at the University of Jaén and member of the Diabetes, Obesity and Nutrition Group of the Spanish Society of Internal Medicine, said:
Is it a high-quality study?
“This study is a randomised, placebo-controlled trial, so we can affirm its methodological robustness for a clinical proof of concept. Furthermore, it incorporates biomarkers and mechanisms of interest in the understanding of metabolic health, such as the gut microbiota, adipose tissue, and lipid and glucose metabolism.”
What are its limitations?
“On the other hand, its sample size is small, the follow-up period is short, and the demonstrated effect on body weight is limited. Furthermore, it does not include other active comparators or biological models that would allow the observed benefit to be confirmed or clarified more precisely.”
What are its implications and how does it fit with existing evidence?
“In this regard, it clearly supports the hypothesis and the role played by our gut microbiota, depending on its profile, in phenomena such as inflammation, dyslipidaemia or diabetes. Likewise, this study identifies the gut microbiota as a genuine therapeutic target in the management of obesity. Furthermore, it is proposed as a complementary tool to supplement pharmacological, nutritional and behavioural strategies, which makes it an interesting option.”
José Pablo Miramontes González, a consultant in internal medicine at the Department of Internal Medicine at Río Hortega Hospital (Valladolid), said:
“The trial with pasteurised Akkermansia muciniphila MucT has a sound design: randomised, double-blind and placebo-controlled, with an initial low-calorie diet phase followed by a 24-week maintenance phase. The primary outcome is positive: participants treated with Akkermansia regained less weight than those in the placebo group, with a difference of approximately 2 kg during the maintenance phase, and the effect appeared to be greater in subjects with lower baseline abundance of Akkermansia. Furthermore, the study provides interesting mechanistic data on insulin sensitivity, faecal energy excretion, microbiota and gene expression in adipose tissue, making it biologically plausible rather than merely descriptive. That said, caution is warranted: it is a small, short-term study conducted in a highly selected population and without comparison to current anti-obesity drug treatments. The magnitude of the effect is modest and does not allow us to conclude that this intervention is an alternative to incretin agonists, but rather a possible complementary strategy.
“Mechanistic questions also remain, as there was no active bacterial comparator or modified strains to allow the effect to be attributed with certainty to specific components of Akkermansia. Therefore, in my view, the study is promising, but it should be interpreted as a clinical and metabolic proof of concept, not as definitive evidence to change clinical practice”.
‘Pasteurized Akkermansia muciniphila MucT for weight loss maintenance in people with overweight and obesity: a controlled randomized trial’ by Sarah Mount et al. was published in Nature Medicine at 23:00 UK time on Tuesday the 12th of May 2026.
DOI: https://doi.org/10.1038/s41591-026-04394-7
Declared interests
Prof Kieran Tuohy: “I have no professional or personal connection with the authors. I have had research and consultancy (advisory and led or been involved in supported research projects) with many companies e.g. Danone, Pepsico, Coca-Cola, International Flavours and Fragrances, Danisco, Benio, Cereal Partners Worldwide, Novartis, Muller Dairies, Jordens Cereals, Aboca, Melinda, AB Mauri over the years but none of them have inputted into my contribution here. I get the majority of my current funding from UKRI funded projects.”
Francisco Jesús Gómez Delgado:
José Pablo Miramontes González: He has not responded regarding any conflicts of interest