A team of scientists at Lund University in Sweden has found that certain amino acids in our blood can be connected to both obesity and the composition of the gut microbiota.
Ottosson et al discovered associations between four gut microbiota genera and BMI predictive plasma metabolites, including glutamate and BCAAs; this suggests that these metabolites could be mediators between gut microbiota and obesity, and points to potential future opportunities for targeting the gut microbiota in prevention of obesity. This illustration depicts a 3D computer-generated image of a group of Escherichia coli. Image credit: James Archer, CDC.
An increasing number of research studies indicate that the gut microbiota plays an important role in our health.
It affects our metabolism and can be linked to obesity, cardiovascular disease and type 2 diabetes. Previous studies have shown that people with these diseases have varying occurrence of different metabolites, i.e. small molecules or metabolic residues, in the bloodstream.
The aim of the current study was to identify metabolites in the blood that can be linked to obesity (high body mass index, or BMI) and to investigate whether these obesity-related metabolites affect the composition of the bacterial flora in stool samples.
Lund University’s Professor Marju Orho-Melander and co-authors analyzed blood plasma and stool samples from 674 participants.
The researchers found 19 different metabolites that could be linked to the person’s BMI; glutamate and so-called BCAA (branched-chain and aromatic amino acids) had the strongest connection to obesity.
They also found that the obesity-related metabolites were linked to four different intestinal bacteria (Blautia, Dorea and Ruminococcus in the Lachnospiraceae family, and SHA98).
“The differences in BMI were largely explained by the differences in the levels of glutamate and BCAA,” Professor Orho-Melander said.
“This indicates that the metabolites and gut bacteria interact, rather than being independent of each other.”
By far the strongest risk factor for obesity in the study, glutamate, has been associated with obesity in previous studies, and BCAA has been used to predict the future onset of type 2 diabetes and cardiovascular disease.
“This means that future studies should focus more on how the composition of gut bacteria can be modified to reduce the risk of obesity and associated metabolic diseases and cardiovascular disease,” Professor Orho-Melander said.
“To get there, we first need to understand what a healthy normal gut flora looks like, and what factors impact the bacterial composition. This requires large population studies as well as intervention studies.”
The study is published in the Journal of Clinical Endocrinology & Metabolism.