Does Gut Microbiome Composition Affect Obesity? — Chromatography Investigates

Obesity is one of the biggest problems facing society. Once a problem only in high income countries, the incidence of obesity in low to middle income countries is rising rapidly. Understanding more about obesity is one of the major pathways to understanding the causes and potential cures for obesity. A team from Lund University in Sweden has been looking at the relationship between gut bacteria and raised BMI — an indicator of obesity. Their findings are reported in The Journal of Clinical Endocrinology and Metabolism — Connection between BMI related plasma metabolite profile and gut microbiota.

Obesity — A growing epidemic

The World Health Organization (WHO) has some damning statistics on obesity. World wide obesity has tripled in the last 40 years — with 13% of the adult population and over 340 million children classed as obese in 2016; almost 40% of all adults in the world are classed as overweight. The basic cause of obesity is a simple energy imbalance — more calories consumed than used.

Obesity is defined — by WHO — as abnormal or excessive fat accumulation that may impair health. There are several ways that excessive fat may be defined, but the most common — but not without its detractors — is using body mass index or BMI. BMI is a simple mass to height ratio that is defined as a person’s weight in kilograms divided by the square of their height in meters. But what causes obesity?

Is it in the gut?

Why some people become obese is not really understood. Obviously, what we eat and how active we are plays a major part. But are some people more prone to obesity because of something in their genes or some other aspect of their physiology? And are there biomarkers that could indicate a predisposition to high BMI and obesity?  That is what a team from Lund University set out to discover.

Our gut bacteria are not fully understood, but we do know that the health of our gut flora — the bacteria that inhabit our gut — can determine how healthy we are. It can affect our metabolism and has links to diabetes, cardiovascular disease and obesity.

The Lund study took samples from over 600 people and analysed blood plasma and stool samples using liquid chromatography. The use of liquid chromatography to analyse biological samples is discussed in the article, Enhanced Peptide Identification Using Capillary UHPLC and Orbitrap Mass Spectrometry.

They found 19 different metabolites that could be linked to a person’s BMI — with glutamate and BCAA having a strong connection to BMI. In a press release the team said:

“The differences in BMI were largely explained by the differences in the levels of glutamate and BCAA. This indicates that the metabolites and gut bacteria interact, rather than being independent of each other”.

They state further studies are needed to understand what a healthy gut flora looks like; but in future, we could be using bacteria in our guts to reduce the risk of obesity.