New research is finds links between gut flora, the breath and obesity.
Elevated levels of hydrogen and methane on the breath are clues to microorganisms that colonize the digestive tract.
Given the right conditions, ph, temperature, other bacteria, certain bacteria proliferate. In the case of hydrogen and methane breath, the culprit is M.smithil. M. smithii colonization occurs in the small bowel as well as in the colon. The level and extent of M. smithii colonization is predictive of weight gain.
A person whose exhaled breath contains large amounts of methane and hydrogen is likely to have gut colonization withMethanobrevibacter smithii, which scavenges hydrogen and, during its metabolism, releases methane.
The presence of both methane and hydrogen on breath testing is associated with increased BMI and percent body fat in humans. The hypothesis is that this is due to colonization with the hydrogen-requiring M smithii, which affects nutrient availability for the host and may contribute to weight gain.
Intestinal flora have been implicated in many mechanisms that may contribute to weight gain, including:
- enhanced lipopolysaccharide production leading to insulin resistance,
- suppression of fasting-induced adipose factor,
- suppression of [AMP-activated protein kinase]-
- driven fatty acid oxidation in the liver,
- incretin regulation, and
- increased short-chain fatty acid production and absorption, thereby providing
- increased lipogenic substrates to the host,