Diversity Matters When It Comes To Gut Microbes

Richness of human gut microbiome correlates with metabolic markers; Nature, August 29, 2013

What is the problem and what is known about it so far?

Experts predict that, by 2015, there will be 700 million obese people in the world, all susceptible to obesity-related conditions such as type 2 diabetes and heart disease. Obesity is caused by a combination of environmental factors and genetics, and now recent evidence suggests that the “good” bacteria that live in the human body may also contribute to a person’s risk for obesity. 

Why did the researchers do this particular study?

The gut contains a wide range of bacterial species. The researchers in this study wanted to analyze the genomes of those species and see whether the diversity of bacterial genes is related to health in obese and lean individuals.

Who was studied?

The study included 123 non-obese and 169 obese Danish people.

How was the study done?

The researchers performed a medical examination of each participant and collected samples from their guts. Then they counted the number of bacterial genes in the guts of each participant—the number of genes is related to the diversity of species. The researchers grouped the participants in to either a high bacterial richness group—meaning they had the most variety in their bacterial genes—or a low bacterial richness group. Then, the researchers compared the groups to see whether bacterial gene richness was related to participant health.

What did the researchers find?

Participants with low bacterial richness were more likely to carry more fat, have high cholesterol, and have insulin resistance—a risk factor for type 2 diabetes—than those with high bacterial richness. Obese people in the low bacterial richness group were also more likely to gain more weight over time.

What were the limitations of the study?

The study only included people from Denmark. Also, this study cannot prove that differences in bacteria are the cause of health disparities between people with high and low bacterial richness.

What are the implications of the study?

This study suggests that doctors could someday identify people at high risk of diabetes and other diseases by testing their bacterial genes. It's also possible that beneficial bacterial species could be identified and used to help lower disease risk in people with low bacterial richness.

  • Last Reviewed: February 13, 2014
  • Last Edited: March 31, 2014

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