The Next Diet Fad: Microbiology Style

image_968Kristina Stefanik (12:00 Micro) found this article in Science Daily about the normal microbiota, human diet, and association with body mass index. Another summary of the research was recently up at Here is Katrina’s report:

Just call me the next Dr. Oz (or Bill Nye); I’ve found the secret to becoming skinny! Unfortunately, it’s not in a food or a certain type of exercise…it’s in your breath. You saw it correctly…an indicator in your breath can reveal how likely or unlikely you are prone to weight gain. A study published in The Endocrine’s Society’s Journal of Clinical Endocrinology & Metabolism discovered that people whose breath contains increased concentrations of hydrogen and methane gases are more likely to have a higher body mass index and percentage of body fat.  The presence of these two gases together strongly indicates the existence of a microorganism which supports obesity. It is better known as Methanobrevibacter smithii.

M. smithii takes up residence in the digestive tract- the prime site of absorption of nutrients. Earlier research confirms that this is the principal microorganism in the human gastrointestinal tract responsible for the majority of methane production. About 70% of people have these bacteria in their tract, while 30% have an elevated amount. Under normal circumstances, M. smithii in the digestive tract is viewed as beneficial. It helps us convert food into energy; however, the problem arises when the organism reaches excessive amounts. It operates as hunter for hydrogen emitted from other microbes and uses that hydrogen to produce the methane exhaled in our breath. The other microbes seemingly benefit from this relationship; they flourish and extract nutrients from food more effectively. Therefore, the higher amount of M. smithii, the more efficient the hydrogen-producing bacteria become. Over a long period of time, this uptake of excess nutrients contributes to weight gain. As stated in the article, this essentially allows a person to harvest more calories from their food.

The study analyzed the breath of 792 people. From this, four patterns appeared. The test subjects had normal breath content, increased content of hydrogen, higher concentrations of methane, or higher degrees of both gases. Accordingly, as the article states, the subjects who possessed higher concentrations of both gases had significantly higher body mass indexes and higher percentages of body fat. More specifically, their BMIs were about 2.4 points greater than those with normal levels of the gases and had about six percent more body fat on average.


Ruchi Mathur, MD, director of the Diabetes Outpatient Treatment and Education center, is continuing a study funded by the American Diabetes Association. As the Time article states, she is working with a group of overweight and obese pre-diabetics that tested positive for methane on their breath. Mathur and other researches will begin to test the participants’ glucose tolerance, measure how long it takes for food to travel through their intestinal tract, and take their stool to the lab to determine the amount of calories in it. After this has been established, the participants will then receive an antibiotic to kill the colonies of M. smithii. They will undergo the same procedure and will essentially be able to determine if eliminating the microbes will alter the person’s weight conditions and overall health. It is amazing to think about how something so small could have such a major impact on something like weight gain!


About ycpmicro

My name is David Singleton, and I am an Associate Professor of Microbiology at York College of Pennsylvania. My main course is BIO230, a course taken by allied-health students at YCP. Views on this site are my own.

Posted on September 18, 2013, in Guest Post, You are what you eat and tagged , , , , . Bookmark the permalink. Comments Off on The Next Diet Fad: Microbiology Style.

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