Intestinal Methanogen Overgrowth (IMO)
Methanogens are microbes that produce methane gas. The more methane someone produces the slower their gut transit time is likely to be, so it’s linked to constipation and harder stools.
Methane positive SIBO has recently been renamed IMO because the overgrowth can also occur in the large intestine. Also, the microbes which produce methane are also not strictly bacteria, they are archaea.
Archaea are also single cell organisms, similar in size to bacteria.
Slow motility
One study found that the total gut transit time for people who have low methane was 48 hours which is considered normal. In people with high methane in the gut the transit time was over 84 hours (around 3.5 days).
Is an overgrowth of methanogens always bad?
Methane is found in the gut of around 30-50% of adults, so some people will have high levels of methane producing microbes and have no issues with their digestion at all.
Signs of IMO
The key signs you might have an overgrowth of methanogens are
- Constipation and slow transit time
- Bloating
- Nausea
- Excessive gas
- Possibly struggling to lose weight.
The more methanogens you have, the worse the constipation is thought to be. The only way you can be sure this is the cause of your digestive issues is to test for IMO.
Testing for intestinal methanogen overgrowth
The best way to test for IMO is through a SIBO breath test. This measures the level of hydrogen or methane gas in your breath, which correlates to how many microbes are in the small or large intestine.
If you have IMO then you’ll see a rise in methane levels. Levels of over 10ppm (parts per million) at any time during the 3 hour test could point to intestinal methanogen overgrowth (IMO).
Treating IMO
Can you get rid of IMO naturally?
The main ways to treat IMO depend on your symptoms, gas levels and other health conditions. Treatments could include
- Antibiotics – using a combination of drugs like metronidazole and rifaximin
- Herbal supplements – e.g. allicin, oregano
- Motility support – prokinetics such as ginger, artichoke or 5HTP
- Diet – a high fibre diet is normally recommended for methane
There are drawbacks and benefits to any kind of treatment, and it depends on your overall health, nutritional status, time constraints and symptoms. For example, if you react to high FODMAP foods you may struggle with a higher fibre diet, but there are ways to slowly, carefully increase your fibre.
Herbal antimicrobial treatments can be effective, but take longer and may be more expensive than taking antibiotics. Antibiotics may not be suitable for everyone with IMO.
Diet variety helps in IMO
One of the worst things you can do with IMO is to slow down your gut by undereating, and avoiding all fibre.
Constipation can be improved in many cases with a balance of bulk forming and gel forming fibres. This involves eating adequate variety in vegetables, fruits, wholegrains, nuts and pulses. Some people with SIBO or IMO can react to these kinds of food so you get trapped not knowing what to eat.
If you don’t eat enough food your digestion will slow down, and you may find gas and bloating becomes worse.
Should you take probiotics with IMO?
Taking probiotics with methane dominant SIBO could increase methane levels (but doesn’t seem to affect hydrogen gas levels). It’s not completely clear why this happens, but it’s another reason not to take supplements unless you know you need them.
Probiotics alone cannot ‘cure’ SIBO, and some people even feel worse when taking live bacteria. Some people get on better with spore-based probiotics such as Bacillus strains, because these are thought to only colonise the large intestine rather than adding to the overgrowth in the small intestine
