SIBO and IBS: diarrhea is hydrogen, constipation is methane

Yoshiharu Uno, MD, PhD

In 2016, the relationship between use of PPI and SIBO was denied (1).

However, in that paper, there were two facts.

Diarrhea type IBS is not related with PPI, but is associated with SIBO.

No methanogenic bacteria were detected in this study.

In 2010, constipation is associated with methane (2), and in the 2006 study (3), methane gas in the small intestine was decreased luminal velocity.
 

Organizing these facts lead to the following.

◎Diarrhea type IBS is not related to PPI, but it is linked to the growth of hydrogen producing bacteria.

◎Constipation type IBS is involved in methanogenic bacteria. It may be linked to the use of PPI.
 

References

1.    Giamarellos-Bourboulis EJ, Pyleris E, Barbatzas C, Pistiki A, Pimentel M.Small intestinal bacterial overgrowth is associated with irritable bowel syndrome and is independent of proton pump inhibitor usage. BMC Gastroenterol. 2016 Jul 11;16(1):67. doi: 10.1186/s12876-016-0484-6

2.    Law D, Pimentel M. Proton pump inhibitor therapy does not affect hydrogen production on lactulose breath test in subjects with IBS. Dig Dis Sci. 2010 Aug;55(8):2302-8

3.    Pimentel M, Lin HC, Enayati P, van den Burg B, Lee HR, Chen JH, Park S, Kong Y, Conklin J. Methane, a gas produced by enteric bacteria, slows intestinal transit and augments small intestinal contractile activity. Am J Physiol Gastrointest Liver Physiol. 2006 Jun;290(6):G1089-95.

＃＃＃Critical problem with the study of ref.1 is that it is not examined about pH rise when used for more than 1 year.

In Japan, there are many patients taking PPI or H2 Blocker on long term.

The pH of the stomach increases in proportion to their duration of use.
 

The bacteria associated with methane production are Methaninobrevibacter smithii and Methanospaera stadmagnae.
 

Reference

Triantafyllou K, Chang C, Pimentel M. Methanogens, methane and gastrointestinal motility. J　Neurogastroenterol Motil. 2014 Jan;20(1):31-40.

The growth pH of Methaninobrevibacter smithii  and Methanospaera stadmagnae is 7 or more.　
It disappears at the usual pH of the stomach, and as the pH in the stomach rises by PPI, it easily enters the small intestine.
In the study of Ref.1, the samples were immediately transported and quantitatively cultured using serial dilutions in sterile NaCl 0.9% under aerobic conditions.

Namely, in the study of Ref.1, it was an aerobic condition of pH 7.4.

However, methanogenic bacterias are anaerobic bacteria.

 Analysis by metagenomics is necessary.

Well then, it is the last question.

Why is hydrogen related to diarrhea? 
 

Why is methane related to constipation?

 

Let's ask Bernoulli.

 

＜日本語解説追加＞
低フォドマップ食では、主に、水素ガスの発生を抑制します。
水素ガスは、下痢と関係しているので、下痢型のIBSでは低フォドマップ食が有効です。
しかし、便秘型のIBSでは、フォドマップ食は下痢型よりも有効性が低いのです。
その理由は、便秘はメタンガスと関連しているためです。
メタンガスは、食物繊維が発酵することで増加します。
ですから、便秘型のIBSでは、低フォドマップ食だけではなく、食物繊維の摂取を控える必要があります。また、メタン産生菌を有している場合には、あらゆる有機栄養によって、ガスが発生する可能性もあります。