How successful a particular diet is for an individual may dependent on how diverse their gut microbiome is, the study suggests.
A team of researchers from Chalmers University of Technology in Gothenburg, Sweden, has managed to develop a mathematical model that allows them to explain why patients react in different ways to a particular diet.
"This method allows us to begin identifying each individual bacteria type's metabolism and thus get a handle on the basic mechanisms in human metabolism," reports Jens Nielsen, professor of systems biology and head of the research team.
Between 300 and 1,000 different types of microorganisms can be found inside the human digestive system, and these are referred to as the gut microbiome. An individual's gut microbiome is typically stable, and general composition between individuals is believed to vary on account of genetic factors, transference from the mother at birth, diet and long-term drug use.
While these microbes can play an important role in the metabolism of food, an increasing number of studies have associated the microbiome with human disorders.
In March, Medical News Today published a Spotlight feature article about the gut microbiome, examining its influence on conditions such as cancer, stress and autism.
Despite experts being able to identify associations between gut microbes and such disorders, the exact mechanisms underpinning their interaction with food has yet to be fully understood.
"The human gut microbiome is known to be associated with various human disorders, but a major challenge is to go beyond association studies and elucidate causalities," the authors explain.
Through clinical trials conducted at the Institute of Cardiometabolism and Nutrition (ICAN) in Paris, France, the research team has been able to establish one such causal link.
Improved blood chemistry possibly due to amino acid production
For the study, published in Cell Metabolism, the researchers characterized the gut microbiome of 45 overweight people who were then divided into two groups - one group with a diverse gut microbiome and the other with a low-diversity gut microbiome.
The participants then followed a low-calorie diet for 6 weeks. During this time, the researchers assessed the participants' blood and feces for the content of substances known to be markers of disease and ill health.
While all of the participants lost weight as expected, the researchers found that the participants in the low-diverse group also had reduced content of the substances known to indicate ill health. In comparison, the participants with a diverse gut microbiome were not affected in the manner.
The researchers explain their findings:
"Amongst other things, we have been able to demonstrate that the intestines of the individuals with low-diversity gut microbiome produce fewer amino acids when they follow this diet. This is one explanation for the improved blood chemistry."
According to Nielsen, these findings will help physicians identify overweight patients at an increased risk of cardiometabolic disease who would derive significant benefit from making alterations to their diet.
The team believes that soon, clinicians will be able to make dietary recommendations tailored specifically to a patient's gut microbiome. Prof. Karine Clément, a study author at ICAN, is already looking to the future and follow-up experiments.
"In the long term we might be able to add intestinal bacteria for patients whose metabolism does not function properly," she suggests.
Current forms of probiotics are used to stabilize the microbiota present in the gut, but Nielsen predicts that future forms will aim to add bacteria into the gut environment to integrate with the microbes that are already present and alter microbiome composition.
Recently, MNT reported on a small study suggesting that vitamin C supplementation could be as effective as exercise for reducing blood vessel constriction that is increased among overweight and obese adults.