Shenzhen, China -- The MetaHIT consortium, comprised of Institute National de la Recherche Agronomique (INRA), University of Copenhagen, BGI, and other institutes, has investigated the gut microbial composition in a cohort of 123 non-obese and 169 obese Danish individuals. This study showed for the first time that 2 groups of individuals can be distinguished in the population by the richness of gut microbiota. The latest results were published online in Nature today.
Obesity, known as "the modem civilized disease", is a leading preventable cause of death worldwide that increases the likelihood of various diseases, particularly heart disease, type 2 diabetes, and others. It's reported that the obesity epidemic will affect more than 700 million in 2015 and will continue to grow. Each of our guts is colonized by more than 3 pounds of microorganisms. More and more data show that our "other" genome, the microbiome, may have greater consequences on the onset of obesity.
In this study, researchers analyzed the gut bacterial composition of 292 Danish adults by a new analytical approach called quantitative metagenomics. They found two groups of individuals that differ by the number of gut microbial genes and thus gut bacterial richness. A quarter of the cohort is "poor" in bacteria (low bacterial richness), whereas the rest is "rich" (high bacterial richness); Low richness individuals included a significantly higher proportion of obese participants and were as a group characterized by a more marked adiposity.
Their further efforts showed that the low richness microbiota contains higher proportion of pro-inflammatory and lower proportion of anti-inflammatory bacterial species than the high richness one. The two groups of individuals could be almost perfect stratified with very few bacteria, suggesting that simple molecular diagnostic tests, based upon the gut microbiome, can be developed to identify individuals at risk of common morbidities.
When comparing the two groups, they discovered that people with a low richness microbiota have more body fat and less healthy; they are more resistant to the action of insulin, have unfavorably altered blood lipids and show increased blood levels of inflammation markers and white blood cells, bringing them at increased risk of type 2 diabetes and cardiovascular disorders.
Interestingly, researchers also observed that obese people from the low richness group gained on average significantly more weight than the high richness one during the past nine years. Eight particular bacterial species were identified based on their possible protective role against weight gain. These findings could lead to the development of new medical therapies for fighting against weight gain.
Obesity is a major contributor to some of the leading causes of death, and lead to a global metabolic health crisis. The work here provides a solid evidence that studies of alterations in the "other" genome may define subsets of adult individuals with different metabolic risk profiles and thereby contribute to the development of stratified approaches for treatment and prevention of widespread obesity, heart disease, stroke, diabetes and some types of cancer associated with it.