Every human being has a unique intestinal microbiota. Its composition in obese patients can influence the response to treatment with inulin, a dietary fibre, as demonstrated by a study led by UCLouvain researchers.
Inulin is a dietary fibre found in salsify, Jerusalem artichokes, leeks, etc. Consumed in sufficient quantity, it changes the composition of the microbiota, which qualifies inulin as a ‘prebiotic’. It promotes the proliferation of certain bacteria with metabolic properties useful to the ‘management’ of obesity.
UCLouvain and Saint-Luc University Hospital have participated in a first multicentre clinical study,1 including obese patients, aimed at evaluating the impact on health of inulin-based treatment. The first results are being published. In parallel with the clinical study, the team of Prof. Nathalie Delzenne, Food4Gut project leader and lead investigator of the Louvain Drug Institute’s Metabolism and Nutrition Research Group (MNUT), addressed whether patients' initial microbiota conditions their response to inulin treatment.
An original approach
Not surprisingly, sequencing the microbiota of patients included in the clinical study revealed significant differences between patients regarding the bacteria that make up their microbiota. Julie Rodriguez, a postdoctoral fellow who conducted the experiments, selected four patients with different microbial profiles. ‘First,’ Prof. Delzenne explains, ‘she transferred microbiota harvested from their faeces into mice previously treated with antibiotics. Second, she put the different groups of mice on the same fat-rich diet. Half of the mice in each group also received inulin. The other half served as a control to assess the treatment’s effectiveness. To quantify possible differences in response to treatment, various metabolic parameters were measured in each group: composition of microbiota, blood sugar, body mass, lipid levels in the liver, etc. This was all compared to the first results obtained in human patients in the clinical study.’
A ‘winning’ bacterial combination
The study’s results2 are astonishing.
First, the starting hypothesis was confirmed: microbiota composition influences the response to inulin therapy. Indeed, the mice that received microbiota from a particular patient lost more weight than the others.
Second, the presence at higher rates of certain types of bacteria is associated with an improvement in certain metabolic parameters. Ditto in humans. Obese patients who had elevated levels of Akkermansia, Anærostipes and Butyricicoccus at the start of the study lost more weight than the others.
Exciting prospects
These results raise other questions and open up new research possibilities. Examples:
- What interaction mechanisms are at work between inulin and bacteria?
- Would prior administration of the different bacteria identified before inulin treatment increase their effectiveness?
- Would the same ‘winning’ bacterial combination interact with other dietary fibre in the same way? Or is it specific to inulin?
- Ms Rodriguez’s experiments improved markers of non-alcoholic steatohepatitis, better known as ‘fatty liver disease’.3 Is this a potential new therapeutic avenue? There is no effective drug treatment for this pathology.
‘It’s now clearly established that the microbiota influences human health’, Prof. Delzenne concludes. ‘From here, the differences between microbiota and the microbial changes induced by food, even by drugs, deserve to be investigated further.’
Candice Leblanc
Notes (1) J. Rodriguez et al., ‘Discovery of the gut microbial signature driving the efficacy of prebiotic intervention in obese patients’, in Gut, 20 February 2020 (posted online). (2) Bifidobacteria, for example, use inulin as a substrate. (3) Non-alcoholic steatohepatitis (NASH) is a pathological overload of fats in the liver.
A glance at Nathalie Delzenne's bio
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Delzenne has been a UCLouvain professor of biochemistry, metabolism and nutrition since 1995. She is president of the Louvain Drug Research Institute. She earned UCLouvain master’s and PhD degrees in pharmaceutical sciences in 1986 and 1991, respectively. She also completed postdoctoral training in human nutrition at the University of Lausanne. Her research focuses on the therapeutic value of certain nutrients interacting with the intestinal microbiota, especially in a pathophysiological context (obesity, diabetes, etc.).. |
A galnce at Julie Rodriguez's bio
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Julie Rodriguez has been a researcher at UCLouvain’s Louvain Drug Research Institute since 2016. She holds a master’s degree in biology and health and a PhD in physiology and molecular and cellular biology, earned respectively in 2008 and 2011 at the University of Montpellier II (France). A UCLouvain researcher since 2012, she focuses on the impact of certain micronutrients on the microbiota and health. |