Wednesday Aug 27, 2014 (foodconsumer.org) -- Early reported on foodconsumer.org, a new study led by Halmosemail et al. shows that a diet low in fermentable saccharides (oligo-, di- and mono-) and polyols (FODMAPs) lowers gastrointestinal symptoms in patients with irritable bowel symptoms (IBS) including bloating, abdominal pain, passage of wind in IBS patients.

Another recent study conducted by Staudacher et al. explains why a FODMAP diet can effectively help IBS in some patients.  According this and other reports, fermentable carbohydrates excluded from the FODMAP diet would otherwise allow gut bacteria to produce gases like hydrogen and methane that can cause bloating and flatulence.  

Still another new study led by Zhang et al. suggests that intestinal bacteria can produce a potential toxic metabolic called methylglyoxal or pyruvaldehyde from carbohydrates such as sugar and the compound may play a role in symptoms of IBS.   This study may also suggest that taking amino acid/protein supplements may help IBS.

The association between methylglyoxal and IBS found by Zhang et al. may also be another reason why a FODMAP diet can help IBS as high concentrations of fermentable carbohydrates  would otherwise lead to high production of methylglyoxal.

One speculation: If methylglyoxal is indeed linked to IBS, then diabetic patients may be at higher risk of IBS because they tend to have high concentrations of methylglyoxal and other reactive carbohydrate metabolites in their blood.

Actually, James D. Wolosin, MD, FACP, and Steven V. Edelman, MD reported that "as many as 75% of patients visiting diabetes clinics will report significant GI symptoms." and "common complaints may include dysphagia, early satiety, reflux, constipation, abdominal pain, nausea, vomiting, and diarrhea.

It remains unknown whether methylglyoxal plays any role in IBS although Zhang et. al. have found evidence to suggest that high levels of methylglyoxal as one factor may be involved in IBS.

Methylglyoxal is a highly reactive aldehyde that can easily with amino acids and protein causing all sorts of  molecular and cellular damage.  There are two ways to reduce the serum level of methylglyoxal, reducing intake of all fermentable carbohydrates to reduce the production of methylglyoxal and taking protective agents to prevent the damage induced by the metabolite.  

The FODMAP diet excludes fermentable carbohydrates so this diet is known to be helpful.  What can be done to prevent the damage induced by high levels of methylglyoxal and other metabolic aldehydes.  One thing IBS patients can do is take amino acids supplements such as glycine and lysine, the former is cheap and readily available and the other is an essential amino acid, which at high levels can also prevent relapses of herpes infection.  Other amino acids may also help.  High serum amino acids can complete with proteins/enzymes to prevent methylglyoxal and other aldehydes from reacting with protein/enzymes.  This concept has been used in cosmetics, that is, creams and lotions with high peptides and amino acids protect against skin damage induced by reactive chemicals.

If amino acid supplements are not an option, then one should increase intake of protein, which can be hydrolyzed in vivo into individual amino acids.  Protein can come from diet or supplements such concentrate whey proteins or whey protein isolates.   This approach may be helpful to patients with IBS and or diabetes mellitus and even healthy people because exogenous amino acid and protein in the blood may prevent the same detrimental reaction (glycation) and slow the aging process.

Also be aware that high fructose corn syrup contains fairly high levels of reactive dicarbonyls like methylglyoxal, according to a study conducted by Dr. Chi-tang Ho and colleagues at Rutgers University.  This compound is also found high in manuka honey.  Both IBS and diabetic patients may be better off avoiding these sweetners. (David Liu)

Emma P. Halmosemail, et al.  A Diet Low in FODMAPs Reduces Symptoms of Irritable Bowel Syndrome, Gastroenterology, Volume 146, Issue 1, Pages 67–75.e5, January 2014

Staudacher HM, Irving PM, Lomer MC, Whelan K., Mechanisms and efficacy of dietary FODMAP restriction in IBS.  Nat Rev Gastroenterol Hepatol. 2014 Apr;11(4):256-66.

Zhang S, Jiao T, Chen Y, Gao N, Zhang L, Jiang M., Methylglyoxal Induces Systemic Symptoms of Irritable Bowel Syndrome.  PLoS One. 2014 Aug 26;9(8):e105307. 

James D. Wolosin, MD, FACP, and Steven V. Edelman, MD, Diabetes and the Gastrointestinal Tract, CLINICAL DIABETES, VOL. 18 NO. 4 Fall 2000