Breath Test Might Predict Obesity Risk

It works by measuring bacteria balance in the gut, researchers say

By Denise Mann

HealthDay Reporter

TUESDAY, March 26 (HealthDay News) -- A simple breath test may be able to tell if you are overweight or will be in the future, a new study suggests.

According to the findings, results from a standard breath test used to assess bacterial overgrowth in the gut can also tell doctors if you have a high percentage of body fat.

The microbiome, or the trillions of good and bad bugs that line your gut, can get out of balance. When bad bacteria overwhelm good bacteria, symptoms such as bloating, constipation and diarrhea may occur. The new study, appearing in the April issue of the Journal of Clinical Endocrinology & Metabolism, suggests that this scenario may also set someone up for obesity.

For the study, individuals drank a sugary lactulose syrup. Breath samples were then collected every 15 minutes for two hours. Participants also had their body fat measured in two ways. One was body mass index (BMI), which takes height and weight into account. The other method uses low-wattage electrical conductivity, which differentiates between lean and fatty tissue.

Those participants whose breath samples showed higher levels of two gases -- methane and hydrogen -- had higher BMIs and more body fat than participants who had normal breath or a higher concentration of only one of the two gases, the study showed. This pattern suggests that the gut is loaded with a bug called Methanobrevibacter smithii, the researchers explained.

It's possible that when this type of bacteria takes over, people may be more likely to gain weight and accumulate fat, said lead study author Dr. Ruchi Mathur, director of the outpatient diabetes treatment center at Cedars-Sinai Medical Center in Los Angeles.

Although there are other ways to measure body fat and BMI, the researchers suggested that individuals with higher methane and hydrogen content in their breath may be more likely to respond to specific weight loss methods down the line. "Obesity is not a one-size-fits-all disease," Mathur said.

If the study findings are confirmed, certain weight-loss treatments could be matched to people who have this breath pattern. One possibility, for instance, might be that probiotics, which help restore and maintain the natural balance of organisms in the gut, could have a role in treating or preventing obesity.

But the science is not there yet, experts cautioned.

"This is an important study looking at bacteria in the intestine and how they are related to BMI," said Dr. Spyros Mezitis, an endocrinologist at Lenox Hill Hospital in New York City. "The more methane and hydrogen in the breath, the higher the body fat." But, "we need more studies to figure out how bacteria is related to the growing obesity epidemic and what happens if we modify it," Mezitis said.

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