Methane and SIBO

Many of us are now very familiar with the role bacteria play in our digestive, and systemic, health, but not as many are likely familiar with the role of archaea.

What Are Archaea?

It has been estimated that about 33% of the world’s human population is considered to be methane producers

Archaea are single-celled microorganisms with a structure similar to bacteria. However, they are evolutionarily distinct from bacteria. Archaea are anaerobes, living in environments low in oxygen (e.g., water, soil), but have recently been described in the human intestine also.

Unlike bacteria, which primarily produce hydrogen, the archaea produce methane gas, and thus are sometimes referred to as ‘methanogens’. Also unlike our bacteria, where we have hundreds of different bacterial species, the human body harbors only a handful of methanogen species.

Interestingly, Archaea have been shown to be absent during infancy while omnipresent in school-aged children, suggesting that colonisation may result from environmental exposure during childhood.

In humans, methanogens have been studied in the gastrointestinal tract, mouth, and vagina, and considerable focus has shifted towards elucidating their possible role in the progression of diseaseconditions in humans (Chaudhary et al., 2018).

The Role Of Methane In Health & Disease

Methane production in the gut is known to be associated with slow gut transit

The role of archaea in gut health and disease remains unclear. However, methanogens are associated with periodontal disease, and have been strongly associated with constipation.

Interestingly, elevated levels of methanogens have been found in obesity, but also in individuals who suffer with anorexia.

Convincing evidence is accumulating that links methanogenic populations of the gut to inflammation. Initial studies found that there is a correlation between methane excretion and IBD (Inflammatory Bowel Disease). In UC and CD patients, a mere 10 to 30% were methane producers, compared to 50% in control groups.

However methanogens have also been associated with periodontitis, diverticulitis, anorexia, obesity, and they have also been found in greater levels in elite cyclists compared to amateur cyclists. And most interestingly in this scenario the elite cyclists weren’t constipated.

Testing For Methane Producing Archaea

There are two tests that may be helpful when suffering with digestive complaints, such as constipation.

Firstly, you can assess levels of archaea via stool testing. Click here to order a stool test from Healthpath, and receive a personalised report of your results.

Secondly, breath testing used to assess for small intestinal bacterial overgrowth, or SIBO for short, (a common cause of Irritable Bowel Syndrome) will look at both hydrogen and methane gases. When methane is elevated, especially throughout the test, it may indicate an overgrowth of archaea in the large intestine. Click here to order a breath test to assess for SIBO.


Methanogens in humans: potentially beneficial or harmful for health, Appl Microbiol Biotechnol. 2018 Apr;102(7):3095-3104

Archaea and the human gut: new beginning of an old storyWorld J Gastroenterol. 2014 Nov 21;20(43):16062-78

Archaea and the human gut: New beginning of an old story, Front Microbiol. 2017; 8: 355

Chaudhary et al., (2018) Methanogens in humans: potentially beneficial or harmful for health

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