Oatmeal is the proverbial poster child for a heart-healthy breakfast. It’s an excellent source of satiating complex carbohydrates and a top source of beta-glucan, a highly viscous soluble fiber that helps reduce high cholesterol levels. As a whole-grain food -- even the instant variety retains all parts of the grain kernel -- oatmeal also contains a significant amount of insoluble fiber, the type that affects digestion.
Fiber and Digestion
Insoluble fiber accounts for roughly 75 percent -- or 3 grams -- of the 4 grams of dietary fiber in a 1-cup serving of regular oatmeal, according to the U.S. Department of Agriculture. Insoluble fiber stimulates digestive activity, helps sweep material through your intestinal tract and promotes bowel regularity. Despite these important health benefits, fiber-rich foods can leave you feeling temporarily bloated and full -- particularly if your diet is otherwise low in fiber. While feeling uncomfortably full or bloated can also be a sign of indigestion, more telltale symptoms include mild discomfort, pain or burning in the upper abdomen.
Effects of Processing
The extent to which oats are processed determines how quickly they cook as well as how easy they are to digest. Because steel-cut oats are simply sliced lengthwise, they’re denser, chewier and longer-cooking than other varieties. Rolled oats are heated and pressed flat to cook faster, while the instant variety is precooked, pressed flat and dried to cook as quickly as possible. Cutting, heating and pressing break down the structure of the grain, which means that more processed oats contain less insoluble fiber -- and are slightly easier to digest -- than less processed varieties. According to the USDA, only about 44 percent of the 4 grams of fiber in a cup of instant oatmeal comes from insoluble fiber.
Anything you do to soften oats -- including soaking, microwaving or boiling -- effectively begins breaking them down before you eat them, thereby making the job a little easier for your digestive system. Raw oats are far harder to digest that cooked oats, which explains why muesli -- a European dish consisting of raw rolled oats, grated apple and walnuts -- is typically soaked in milk prior to serving. Even oats that you plan to cook are easier to digest if you allow them to soak overnight before you cook them. Likewise, steel-cut oats that are cooked to a softer consistency are generally easier to digest than those that remain firm.
Although indigestion has many possible causes, it’s frequently triggered by anxiety or stress, eating too much or too fast, drinking alcohol and eating spicy, fatty or greasy foods. While fiber-rich foods can also trigger indigestion, it’s less likely to occur in people who are accustomed to a high-fiber diet. Consuming smaller portions, eating slowly and chewing your oatmeal thoroughly may help relieve or minimize symptoms of indigestion. Boosting your fiber intake gradually over the course of a few weeks can also help. Be sure to drink plenty of fluids as well -- without enough water, fiber tends to slow the digestive process.