Irritable Bowel Syndrome, or IBS, is commonly divided into two main types: “IBS-C” (IBS with constipation) and “IBS-D” (IBS with diarrhea). This article focuses on IBS-C.
GOLDEN RULE OF IBS-C: IBS-C is primarily about indigestion. If a food is hard to digest, it will slow things down. It’s that simple.
When exploring the connection between your symptoms and these foods for yourself, keep in mind that poorly-digested foods can cause delayed or prolonged symptoms because they are processed so slowly. Most of these foods can affect digestion for several days after you swallow them. It is also important to recognize that sluggish digestion can cause all kinds of other problems north of the intestines, including heartburn and reflux (“GERD”).
THE FIVE MOST COMMON CULPRITS:
- GLUTEN. Gluten is a sticky protein found in wheat, barley, rye, and triticale. This protein has a special globular structure that is very hard for our enzymes to digest.
- CASEIN. Casein is a sticky protein found in most dairy products. Baby cows come with a special enzyme in their stomachs called rennet, which is designed especially to break down casein. Humans do not have rennet, so casein is very hard for us to digest. Hard cheeses and high-protein yogurts (such as “Greek style” yogurts) are especially good at triggering IBS-C.
- CRUCIFEROUS VEGGIES. Lots of veggies happen to be crucifers, including broccoli, kale, and cabbage. This veggie family contains high amounts of an indigestible short-chain carbohydrate (or oligosaccharide) called raffinose. Human enzymes cannot break down raffinose into sugar, but bacteria in the colon love to munch on raffinose and turn it into a lovely gas called methane. This will not only make you unpopular at parties, but can slow digestion and cause significant bloating and discomfort, as well.
- LEGUMES. Legumes are beans and pod vegetables, including soy, lentils, green beans, peas, and garbanzo beans. There are two main reasons why these foods are hard to digest. One is that they contain lots of raffinose (see #3), and the other is that they contain high amounts of soluble fiber. Soluble fiber acts like a sponge in the digestive tract—it absorbs water and swells into a big sticky gel that can form a large, lovely CLOG. Soluble fiber cannot be digested except by bacteria in the colon, so it also eventually forms delightful gases.
- NUTS. Nuts are very closely related to legumes. Nuts and legumes are both types of seeds, and therefore contain similar compounds, namely indigestible short-chain carbohydrates and soluble fiber. All seeds also contain enzyme inhibitors which interfere with our ability to digest the proteins within these foods. These inhibitors are damaged or destroyed by cooking, but we often do not cook nuts before eating them. This may be why some people find nuts even more difficult to digest than legumes, which are always thoroughly cooked before eating.
The above are just the most likely suspects in constipation, but keep in mind that everyone is different, and these are not the only foods that can cause problems for people. In my clinical experience I have had patients tell me that lots of other foods can be problematic, including raw vegetables of all kinds, gelatin (especially if very concentrated, such as in gummi candies), grains (even those that do not include gluten, such as rice), and fruits high in pectin and insoluble fiber, such as apples and bananas.
How about you?
If you have noticed any connection between the foods you eat and your symptoms, and you’d like to share your experience, please leave a comment below so that we can all learn from one another.