Why overweight and obese people gain weight and how to shed it is one of the most prolific areas of written articles and perhaps metabolic research. The study the human gut microbiome and its impact on health and nutritional status is the focus of some of that research.
One question that research at The Gordon Lab, the Center for Genome Sciences & Systems Biology, Medical University, Washington University in St. Louis, is trying to answer is; "Can we intentionally manipulate the functional properties of our gut microbial communities to improve human health?"
Based on a study published in the journal Science and on the ScienceDaily.com website, this research has "led to one of the latest advances in learning what role the bacteria in the gut plays in the weight management."
Vanessa Ridaura, a graduate student at Washington University's School of Medicine, and colleagues, studied "the gut bacteria from pairs of both fraternal and identical twins in which one sibling was lean and one was obese." The gut bacteria from each twin was transplanted into mice that were bred bacteria free ... "the lean twin’s bacteria ("slimming microbiota ") into one group of mice and the obese twin’s bacteria (“fattening microbiota”) into another."
The mice that received the lean twin’s "slimming microbiota " remained lean and the mice that received the obese twin’s "fattening microbiota " were fatter and adopted metabolic changes associated with obesity in humans, even though both groups of mice ate the same "mouse" diet. The components of microbes making up of human microbiota then became the focus of the study.
So, the researchers performed what Jeffrey Gordon, director for the Center of Genome Sciences and Systems Biology at Washington University School of Medicine and a co-author of the Science report called "The Battle of the Microbiota,"
Within 5 days of additional mice getting the microbes from the twins, one mouse from each group of "fattening microbiota" and "slimming microbiota" was placed in a cage. The gut microbes from the mice in each cage got mixed because mice consume each others feces, referred to as, coprophagia.
Previous studies from the literature showed "that the variety of microbial genes in one's gut can influence obesity -- and that high-fiber food, such as fruits and vegetables, tends to boost such bacterial diversity." Some of the pairs of caged mice in the Washington University's School of Medicine study were fed a diet that was high in fruits and vegetables and low in saturated fat.
After these mice had been cage mates for 10 days, the researchers discovered that, both the original "fattening microbiota" and the "slimming microbiota" mice "had adopted "leaner" features, including the metabolic features, when fed a diet that was high in fruits and vegetables and low in saturated fat.
Others mice from the same co-inhabiting groups that were fed a diet high in saturated fat and low in fruits and vegetables. The researchers now discovered that, original "slimming microbiota" mice continued to adopt "leaner" features, including metabolic features. However, the original "fattening microbiota" mice adopted "fatter" features, including metabolic changes associated with obesity in humans.
Conclusions based on theory:
- The "slimming microbiota" were able to invaded the mice, that originally had the "fattening microbes" more freely when the mice were fed a diet high in fruits and vegetables and low in saturated fat because the diet.
- Conversely , they "slimming microbiota" were resisted in invading the mice that originally had the "fattening microbes" when these mice were fed a diet high in saturated fat and low in fruits and vegetables, because this type of diet did not encourage the growth of a more diverse accumulation of microbes in the gut.
- The mice with the original "slimming microbiota" that did not gain weight with either diet started off with a more diverse accumulation of microbes in the gut. This supports previous research that suggests obese people have fewer and less diverse microbes in their gut than lean people.
- “We think the lack of diversity leaves open niches that can be filled by microbes associated with leanness,” explained co-author Gordon. How do the diverse microbes affect weight gain? According to Gordon, the bacteria in "lean mice digested more fiber, so they gave off more short-chain fatty acids than the bacteria in the obese mice." "Short-chain fatty acids are thought to cause "less fat to accumulate in fat cells, boost calorie burning, and increase satiety hormones."
Rob Knight, a microbiologist at the University of Colorado said, “... it’s possible that we could eventually prevent or treat obesity by giving people the right microbes and the right diet.”
This information is not intended to replace a one-on-one relationship with a qualified health care professional and is not intended as medical/nutritional/fitness advice. Information presented is subject to change as additional discoveries are made or additional research is published.
Sources: http://www.sciencedaily.com/, Science 341: 1079, 2013; American Association for the Advancement of Science, http://www.audioenglish.org/dictionary/, www.examiner.com/article/changing-your-gut-bacteria-to-lose-weight?no_cache=1387042581, http://www.colorado.edu/, http://en.wikipedia.org/wiki/,