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Health Care, Healthcare, Public Health, Science, Uncategorized, Women's Health

Body Weight Is Heavily Influenced By Gut Bacteria, New Study Finds

obesity 4

Previous research has linked both genetic variation and the composition of gut microbes to metabolic disease and obesity. Despite these shared effects, the relationship between human genetic variation and the diversity of gut microbes was presumed to be negligible.

Now, a new study has expanded on this concept, revealing that our genetic makeup shapes what type of bacteria live in the gut, which may affect how heavy we are.

By studying pairs of twins, researchers identified a specific, little known bacterial family that is highly heritable and more common in individuals with low body weight. This microbe also protected against weight gain when transplanted into mice.

The results, published this week in the journal Cell, could pave the way for personalized probiotic therapies that are optimized to reduce the risk of obesity-related diseases based on an individual’s genetic make-up.

In the study, funded by National Institutes of Health (NIH), researchers sequenced the genes of microbes found in more than 1,000 fecal samples from 416 pairs of twins. Of these twins, 171 pairs were identical and 245 were non-identical. Identical twins share 100% of their genes, while non-identical twins share around 50% of their genes.

Gut bacteria are ‘an exciting new target’ for obesity prevention efforts

Results of the analysis revealed that identical twins had a similar abundance of specific types of gut bacteria, compared with non-identical twins. This indicates that genes influence the type of bacteria found in the gut, the researchers say.

What’s more, the team found that the presence of a class of bacteria called Christensenellaceae was most influenced by genes. A certain strain of this bacteria – Christensenellaceae minuta – was found to be more abundant among individuals of a low body weight than in obese individuals. Moreover, mice that were treated with this microbe gained less weight than untreated mice, suggesting that increasing the amounts of this microbe may help to prevent or reduce obesity.

“Our findings show that specific groups of microbes living in our gut could be protective against obesity — and that their abundance is influenced by our genes,” says study author Dr. Tim Spector, Head of the Department of Twin Research and Genetic Epidemiology at King’s College London. “The human microbiome represents an exciting new target for dietary changes and treatments aimed at combating obesity.

Gut bacteria as a modifiable risk factor for obesity

Up until now, variation in the abundances of gut microbes has been explained by diet, the environment, lifestyle, and health, the authors note. This is the first study to firmly establish that certain types of gut microbes are heritable — that their variation across a population is in part due to host genotype variation, not just environmental influences.

“These results will also help us find new predictors of disease and aid prevention,” adds co-author Dr. Ruth Ley, Associate Professor at Cornell University. Indeed, these findings add to a growing body of research indicating that natural gut bacteria play a role in the development of a range of metabolic disorders including obesity, diabetes and cardiovascular disease.

For example, one recent study found that obese individuals have lower levels of a beneficial bacteria in the gun than do thin people; the levels increased with weight loss, suggesting that obesity has a “microbial component.” Results of another recent study suggest that gut bacteria might even trigger the pathogenic processes of insulin resistance, obesity, and diabetes.

These links are further borne out in observational research, which has found that certain dietary factors that alter gut bacteria composition are also associated with the risk of obesity. For example, a study published in September uncovered evidence that consumption of artificial sweeteners — like those found in diet sodas and other sugar-free foods — may increase obesity risk by interfering with gut bacteria. Overuse of antibiotics, particularly in early childhood, is another mechanism through which changes in gut bacteria are thought to influence obesity.

The good news? Research also suggests that the addition of certain  probiotics to the diet may help to prevent weight gain, reduce body fat, and mitigate harmful processes linked with insulin resistance and diabetes.

 

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