Does a Low FODMAP Diet Help IBS?

low fodmap spinach
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A novel theory has been proposed regarding the effectiveness of a low FODMAP diet for IBS. FODMAP refers to foods that contain certain short-chain carbohydrates, and stands for Fermentable Oligo-, Di- and Mono-saccharides, and Polyols. The FODMAP theory suggests that when individuals who suffer visceral hypersensitivity and/or motility dysfunction consume high levels of FODMAPs there is an increase in intestinal distension which contributes to digestive symptoms.

A small handful of studies have been published with some promising results. Two studies to date are of particular interest for IBS.

A study published in 2006 devised a diet for IBS patients with fructose intolerance. The diet consisted of four elements: avoidance of foods with high levels of free fructose and "short-chain fructans," limited total fructose load, recommendation of foods with balanced fructose/glucose levels, and intake of free glucose. Telephone follow-ups were conducted following the assignment of the diet within two to forty months after the start of the diet. Results showed an admirable adherence to the diet at a rate of 77 percent. An encouraging 74% of the patients experienced a decrease in abdominal symptoms. These results are promising, but the lack of a comparison control group and the lack of precision in terms of elapsed follow-up time, limits the ability to generalize these results.

A study published in August of 2010 compared the effects of a high FODMAP diet on fifteen IBS patients versus fifteen healthy individuals. Participants were given either high or low FODMAP diets to follow for two days. The high FODMAP diet induced digestive symptoms and lethargy in the IBS patients.

The only symptom reported by the healthy individuals during the high FODMAP days was an increase in intestinal gas.

My Bottom Line

What is most intriguing about the FODMAP theory for IBS is that stress is not even mentioned. We have come a long way, baby! Ten years ago, IBS research was all about psychological factors, with a strong minimization of dietary contributions. In this regard, scientists and patients were clearly ensconced on opposite sides of the fence. The FODMAPs theory thus attempts to address what IBS patients have been saying for years: "My IBS is worse when I eat...".

It is so heartening that continuing research into the area is finding that following a low FODMAPs diet is effective in reducing IBS symptoms in approximately three quarters of  patients.  This suggests that following a low FODMAPs diet is a good option if you have not had success in relieving symptoms through standard medical care.


Ong, D. "Manipulation of dietary short chain carbohydrates alters the pattern of gas production and genesis of symptoms in irritable bowel syndrome" Journal of Gastroenterology and Hepatology 2010 25:1366-1373

Shepherd, S. & Gibson, P. "Fructose Malabsorption and Symptoms of Irritable Bowel Syndrome: Guidelines for Effective Dietary Management" Journal of the American Dietetic Association 2006 106:1631-1639

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