Individual variability in the gut microbiome affects every aspect of human health; new research from Seattle’s Institute for Systems Biology explored the functional determinants of how differences in the taxonomic composition of the gut affect the body’s response to weight loss interventions. The findings were published in mSystems, an open-access journal of the American Society for Microbiology (2021. DOI:10.1128/mSystems.00964-21).
Lead scientist Christian Diener, PhD, and team enrolled a cohort of 105 individuals selected from a larger population enrolled in a commercial wellness programme; 48 had lost more than 1% of their body weight per month over a six- to 12-month period, while 57 lost no weight and had a stable body mass index (BMI) over the same period. Each individual in the cohort had baseline blood metabolomics, blood proteomics, clinical labs, dietary questionnaires, stool 16S rRNA gene sequencing data, and follow-up data on weight change. In a subset of 25 individuals who showed the most extreme weight change phenotypes, the researchers generated additional targeted proteomics data on obesity-associated proteins in blood before and after intervention, and baseline stool metagenomic data.
After controlling for sex, age and BMI, the research team identified 31 baseline stool metagenomic functional features associated with weight loss responses. These included complex polysaccharide and protein degradation genes, stress-response genes, respiration-related genes, and cell wall synthesis genes, as well as gut bacterial replication rates. The team concluded that the microbiota may influence host weight loss responses through variable bacterial growth rates, dietary energy harvest efficiency and immunomodulation. Therefore, there could be an opportunity to alter the gut microbiome to impact weight loss, or to offer appropriate guidance on diet alterations to individuals whose gut bacteria may confer resistance to weight loss.
In a statement on the study results, Dr Diener commented: “Before this study, we knew the composition of bacteria in the gut were different in obese people than in people who were non-obese, but now we have seen that there are a different set of genes that are encoded in the bacteria in our gut that also responds to weight loss interventions. The gut microbiome is a major player in modulating whether a weight loss intervention will have success or not. The factors that dictate obesity versus non-obesity are not the same factors that dictate whether you will lose weight on a lifestyle intervention.”