Obesity could have different causes in men and women, study finds

Researchers have discovered that different gut bacteria can lead to obesity in men and women. (Getty Images)
Researchers have discovered that different gut bacteria can lead to obesity in men and women. (Getty Images) (Ableimages via Getty Images)

Obesity has been linked to a number of causes, from high calorie intake to genetics, but now scientists believe our gut bacteria could also play a crucial role.

A new study has found that the bacteria in our gut can mean the difference between leanness and health and higher BMI, fat mass and waist circumference – and it’s different for men and women.

The gut microbiota consists of a complex community of microorganisms, bacteria, viruses, fungi and protozoa, which inhabit the gastrointestinal tract.

Disruption in this community significantly affects metabolic health and influences the risk of certain diseases, including obesity.

To find these results, which will be presented at this year’s European Congress on Obesity (ECO) in Venice, the research team studied stool samples from 361 adult volunteers in a randomised trial examining the relationship between genetic variants and the response to a low calorie diet.

All of the participants were then classified into categories based on an obesity index.

Genetic microbiota profiling was done to identify the different types, composition, diversity, and relative abundance of bacteria present in stool samples of the participants.

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Gut bacteria in obese people is more commonly linked to high BMI. (Getty Images) (Carol Yepes via Getty Images)

The analysis revealed that individuals with a high obesity index had significantly lower levels of Christensenella minuta – a bacterium which has consistently been linked to leanness and health.

In men, greater abundance of Parabacteroides helcogenes and Campylobacter canadensis species – were strongly associated with higher BMI, fat mass, and waist circumference.

Whereas in women, greater abundance of three species – Prevotella micans, Prevotella brevis and Prevotella sacharolitica – were highly predictive of higher BMI, fat mass and waist circumference, but not in men.

Through further testing with blood samples they discovered that there was variation in abundance of certain metabolites, the end product of metabolism, in obese participants.

The researchers therefore conclude that men and women need different interventions to help prevent obesity.

"Gut microbiome composition, specifically higher levels of the Christensenella minuta bacterium, appeared to protect against obesity," Dr Paula Aranaz, from the University of Navarra in Spain, said.

"Whereas the species that influence the risk of developing obesity appear to be different between the sexes and interventions to help prevent an obesity-favourable microbiome may need to be different in men and women.

"Further research is needed to better understand when the switch to an obesity favourable gut microbiota may take place, and therefore the right timing for possible interventions."

Additional reporting by SWNS.

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