Traditional Dietary Advice vs a Low FODMAP Diet and Gluten-Free Diet for Non-Constipated IBS

The best diet for non-constipated IBS

In the United Kingdom, the most recommended diet for IBS-diarrhea and IBS-mixed is traditional dietary advice (TDA). These recommendations include eating regularly and avoiding large meals; staying hydrated; limiting the intake of ETOH, caffeine, and fizzy drinks; avoiding fatty, spicey, and processed foods; not eating more than three servings of fruit daily; avoiding gas-producing foods including excess fiber, beans, bread and artificial sweeteners; and lastly, removing any food intolerances.

In North America, The FODMaP diet is the top recommended diet for IBS. It reduces fermentable sugars in the diet. A previous study comparing a low FODMaP diet with a diet similar to the TDA showed that both improved IBS symptoms but the FODMaP diet was associated with a greater improvement.

This study also included a low-gluten diet, maybe in part because it was funded by a gluten-free food company. There were 33 individuals in each group and IBS symptoms were followed using the IBS-SSS tool. A positive response was measured by a >50-point reduction. After 4 weeks, the results showed:

Traditional Dietary Advice                     42% (n = 14/33)      % that would continue the diet: 70%

Low FODMaP Diet                               55% (n = 18/33)      % that would continue the diet: 67%

Low Gluten Diet                                    58% (n = 19/33)      % that would continue the diet: 61%

The TDA was the easiest to incorporate into one’s lifestyle.

There is a lot of overlap among these three diets. For example, a gluten-free diet is low in FODMaP sugars (fructans), and the TDA recommends reducing gaseous foods and any intolerant foods (gluten). If we were going to combine the best of all these diets into one recommendation that was relatively easy to incorporate, it might look like the recommendations I have summarized below into a patient handout.

Dietary recommendations for irritable bowel

• Eat regularly and avoid large meals that may cause distension.
• Avoid alcohol, caffeine, and carbonated or fizzy drinks.
• Avoid spicy and processed foods.
• Avoid more than three servings of fruit daily.
• Avoid foods high in sugar. Sugar feeds the bacteria in your gut resulting in fermentation, gas generation, and bloating. Avoid excess foods made from white flower (bread, bagels, pasta, etc). Avoid excess dairy (lactose sugar). Avoid sweeteners, particularly those that end in “-ol” such as xylitol and sorbitol.
• Read food labels. Pay attention to the “added sugar” line. It will include the amount of added sugar per serving. Of note, 5 g will equal one teaspoon of added table sugar. Keep this as low as possible.
• Avoid foods that you may be intolerant to. The two most common are gluten and cow’s milk protein (dairy). Unless you have lactose intolerance or celiac disease, you don’t have to remove these altogether but reducing the total amount in your diet can have beneficial effects.
• Avoid excess fiber. Fiber is one of the most beneficial nutrients; however, excess amounts can also feed the gut bacteria leading to gas generation and bloating. High-fiber foods can be found in beans, uncooked vegetables, nuts, psyllium, bran, and flax seed among others. These foods are good for you, but if you are eating a lot of them, try cutting back.
• Finally, relax and enjoy your meals. Eating while under stress reduces digestive enzymes, increases spasms of the bowels, and can significantly worsen symptoms.