Oats are a healthy grain for most people, and the main ingredient in oatmeal. Oatmeal and bloating usually don't go together, as oats are very rarely one of those foods that cause bloating and gas. But there are some rare instances where oats can trigger bloating.
Oats cause bloating in a limited number of people because of a few unusual factors. People who are sensitive to gluten may eat oats grown or processed around wheat. Or oats can sometimes cause a reaction in people who are adding fiber to their diet, but this is usually temporary.
Oatmeal and Bloating
Oats, and oatmeal, are high in fiber and protein. Oats are high in soluble fiber, which dissolves easily in water. This is the type of fiber that the Mayo Clinic says can help lower blood cholesterol and glucose levels. But if you haven't been consuming a lot of fiber, and suddenly start eating a lot of fibrous foods, including oats, this can cause stomach bloating, gas and cramping, the Mayo Clinic says.
Instead of adding fiber all at once, add it slowly, allowing your body to get used to your new, healthier diet. Also, drink plenty of water, because water helps oats or any other fibrous food to absorb water, which makes your stools soft and bulky.
If you have irritable bowel syndrome (IBS), you may find that you have some trouble with fiber, according to the International Foundation for Gastrointestinal Disorders (IFGD). Most of the time, it's insoluble fiber that's the problem. This is found in legumes, seeds, root vegetables, wheat bran and corn bran. Some people, however, have a problem with soluble fiber, which includes oats, the IFGD says. The best way to determine the culprit, the IFGD says, is trial and error.
Oats and Celiac Disease
Oats have a protein called avenin, which, along with fiber, is why oats are considered to be a healthy food, according to Harvard Health. For many people who eat a gluten-free diet, especially those with celiac disease, oats are a good way to get nutrients often lacking in the gluten-free diet, according to the Celiac Disease Foundation, or CDF.
Oats, however, are sometimes grown around wheat and barley fields. According to Coeliac UK, reactions can occur to people with celiac if they eat oats that have been exposed to wheat, barley or rye. Eating oats that are labeled gluten-free is best.
A January 2015 study in the Journal of Autoimmunity found that celiac patients who eat a normal amount of oats do not have reactions to oats, as long as they are not contaminated with wheat, barley or rye. This is because people with celiac have trouble digesting the gluten protein because of an immune response. Avenin, the protein in oats, doesn't trigger the same immune response in people, according to CDF.
Fiber and Bloating
If your diet has been lacking in lots of fiber, but you've decided to swap out high-calorie, low-fiber foods for foods high in fiber, then you should see some health gains, says the Mayo Clinic. But you may encounter some bloating and gas in the beginning, as your body adjusts to your new diet. This could be why after eating oats gastrointestinal problems occur.
The solution to that is to increase fiber gradually over a few weeks, says the Mayo Clinic. That will allow the natural bacteria in your system to adapt to your new diet. By sticking to this new diet, you will likely control blood sugar spikes better, see better cholesterol numbers, slow or reverse weight gain and have regular bowel movements.
Still, if you have changed your diet, it's best to discuss these changes with your doctor. That way, if you are feeling discomfort, your doctor can work with you to find the cause and make sure you're eating the healthy diet that's right for you.
- Journal of Autoimmunity: "Ingestion of Oats and Barley In Patients with Celiac Disease Mobilizes Cross-Reactive T Cells Activated by Avenin Peptides and Immuno-Dominant Hordein Peptides"
- Mayo Clinic: "Dietary Fiber: Essential For a Healthy Diet"
- Harvard Health: "The Nutrition Source: Oats"
- Coeliac UK: "Oats"
- The Celiac Foundation: "Oats and the Gluten-Free Diet"
- International Foundation for Gastrointestinal Disorders: "About IBS: Dietary Fiber"