Does a Low FODMAP Diet Improve IBS Symptoms?

A novel theory has found a link between the two

low fodmap spinach
Photo: Lisa Hubbard/Getty Images

If you've been diagnosed with irritable bowel syndrome (IBS), you may be willing to try anything to alleviate the unpleasant symptoms of the disorder, including a low FODMAP diet. If so, you might be on to something, as a novel theory has been proposed regarding the effectiveness of a low FODMAP diet for IBS. With this review, learn what the research says about this diet's impact on the condition.

What Is FODMAP?

Before delving into how effective a low FODMAP diet is for IBS, it's first necessary to know what this term means. FODMAP simply refers to foods that contain certain short-chain carbohydrates. It stands for Fermentable Oligo-, Di- and Mono-saccharides, and Polyols.

The FODMAP theory suggests that when individuals who suffer from visceral hypersensitivity and/or motility dysfunction consume high levels of FODMAPs, there is an increase in intestinal distension, which contributes to digestive upset. A small handful of studies have found promising results about the diet's impact on stomach problems, and two studies are of particular interest for IBS patients.

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 40 months after the start of the diet.

Results showed an admirable adherence to the diet at a rate of 77 percent. An encouraging 74 percent 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 15 IBS patients versus 15 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.

The Bottom Line

What is most intriguing about the FODMAP theory for IBS is that stress is not mentioned. 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 FODMAP 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 FODMAP diet is effective in reducing IBS symptoms in approximately three quarters of patients. This suggests that following such a diet is a good option if you have not had success in relieving symptoms through standard medical care.

Sources:

Ong, D. et.al. "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

Continue Reading