Vegan Diets and Irritable Bowel Syndrome: The FODMAP Approach
By Ginny Messina on March 8, 2016
One of the most frequent questions I get through this website is about the low-FODMAP diet. This popular approach to easing symptoms of irritable bowel syndrome (IBS) eliminates (at least initially) many plant foods. It's definitely a bit of a challenge for vegans, but may be worth it if you suffer from IBS.
The FODMAP Diet
IBS affects as much as 15% of the population in North America, so it is no small problem. And while it's not life-threatening, it can have a significant effect on quality of life.
The idea behind the low-FODMAP diet is that certain fermentable short-chain carbohydrates contribute to symptoms in people with IBS. Some of these carbs are poorly digested and some are not digested at all. Others, like lactose in milk or the sugar fructose, are digested by some but not all people.
Since they aren't digested, these carbs aren't absorbed. Instead, they travel to the colon where they are fermented by bacteria, resulting in gas production. They can also pull water into the lower intestines, creating an uncomfortable feeling of distension. For most people, these effects are not a problem or at least, they are felt to only a minor degree. But people with IBS may be hypersensitive to the effects of water and gas in their lower intestines.
The FODMAP approach limits these fermentable carbs for several weeks to see if IBS symptoms improve. If you feel better after avoiding these foods, the next step is to determine which type of fermentable carbs are responsible for your symptoms. This is achieved by gradually adding foods back one at a time.
Some research suggests that about 75 percent of people with IBS may be helped with the FODMAP approach.