Bloating: excess fullness, distended belly, feeling of pressure, sharp pains or cramping. If you have it, you know it. If it is chronic, it may be bothersome — or worse. Bloating is a symptom, not a medical condition. It can be a symptom of many things. Whole books have been written on the subject. Following is a brief summary of some of the most common digestion-related causes. It is not a comprehensive list of every single cause. This article focuses on food, nutrition, and lifestyle. Diagnostics and medical interventions are not covered here.

Upper Abdominal Bloating: Stomach

Gastroparesis is one cause of bloating. A healthy stomach is at least 65 percent empty two hours after eating and at least 90 percent empty after four hours. For those with gastroparesis, stomach emptying is delayed, leading to uncomfortable symptoms such as getting full quickly, lack of appetite, reflux, heartburn, nausea, and/or vomiting. Dietary therapies can help, including eating smaller, more frequent meals; proper meal timing and spacing; pre-blending foods; and adjusting the fat and fiber content of meals.

Classic indigestion is another upper abdominal cause of bloating. It is often associated with acid reflux and is sometimes referred to as acid indigestion. The bloating can feel like you are swelling up with air in the upper stomach area and often comes on soon after eating. Sometimes there is heartburn, reflux, sore throat, nausea, and/or a sour or metallic taste in the mouth. One aim of dietary management is to prevent your stomach from being either too empty or too full. Eating smaller, more frequent meals; avoiding oversized portions; avoiding high-fat meals; and choosing softer foods versus “tougher” foods like popcorn, nuts, and coarse salads can all be helpful.

Functional dyspepsia is another type of bloating with roots in the stomach. In this case, the nerves and muscles of the stomach do not work properly. The stomach does not stretch properly after a meal, or the flow of food within the stomach – from upper to lower – is impaired. This all leads to feelings of being overfull and painful bloating in the stomach region. Heartburn is not a part of this picture. Dietary modifications include eating smaller, more frequent meals; choosing softer-textured and lower fat meals; avoiding liquids with meals; and sipping beverages slowly.

Lower abdominal bloating: Intestines

Constipation-related bloating is a large topic. There are many different causes, including a lack of fiber, Irritable Bowel Syndrome (IBS), Small Intestinal Bacterial Overgrowth (SIBO), slow transit time, pelvic floor dysfunction (PFD), blockage of the colon, and the use of opioid medications. Constipation can refer to difficulty in moving the bowels, a hard-textured stool, or infrequent bowel movements. Bloating results as the colon fills with stool. Often the abdomen can be rock hard. Gas and lower abdominal cramping may occur. Dietary modifications are as varied as the causes. Fiber is great for some, but not all (for some it can make things worse), and tweaking with the type of fiber often can be helpful. If you need more fiber in your diet, do it gradually, and start with adding more fiber to your breakfast. Eating larger, bulkier, more consolidated meals can help to stimulate the colon. Doing a trial FODMAPs elimination diet can be helpful, as can coffee in the morning and certain supplements. Getting to the root cause of your constipation will allow for a more targeted dietary approach.

SIBO is another common cause of bloating. Normally most of our bacteria live in the colon. In SIBO, there is an overgrowth of bacteria in the small intestine, where they do not belong. When food enters the small intestine, the bacteria feast on this food and ferment it, leading to uncomfortable gas and bloating. Some people experience constipation, while others get diarrhea, or a combination. SIBO often leads to consistent bloating and the feeling that, no matter what you eat, you get bloated. Sometimes the bloating gets worse as the day progresses. SIBO should be treated with antibiotics or antimicrobial herbal therapy or, less commonly, an elemental diet. Dietary modification is usually for symptomatic relief. A low-FODMAP diet is a common way to reduce symptoms. Some recommend a lower carbohydrate approach as long-term therapy. SIBO relapse is common, so being aware of root causes is important.

Carbohydrate intolerance is another common cause of bloating. These include lactose (milk sugar) intolerance, a deficiency in the enzyme lactase. Fructose intolerance is another one. Fructose is a sugar naturally found in certain fruits and sweeteners like honey, agave, and high fructose corn syrup. Some of us cannot adequately absorb fructose due to a lack of enough transporters in the small intestine. Sugar alcohol malabsorption occurs because they are not absorbed in the small intestine. Sugar-free foods like gums and candies contain them, but they are also found naturally in some foods like cauliflower, prunes, and avocado. When these unabsorbed carbohydrates enter the colon, the bacteria there feast on them, producing lots of gas, bloating, and sometimes diarrhea. Last, FODMAPs are a type of highly fermentable fiber. Fiber is by its nature indigestible to humans. When they come in contact with the bacteria living in our large (or small) intestines, they again produce lots of gas to varying degree depending on what bacteria you have living inside of you. For some this is not a problem, but for others it can be distressing. Elimination diets can be very helpful here, such as for lactose, fructose, and FODMAPs, to find out if these foods are in issue for you. There are also enzyme supplements that can help with certain foods such as legumes and brassicas (alpha galactosidase) and lactose in dairy (lactase); and there is a newer enzyme on the market designed to help with fructose intolerance (xylose isomerase).

There are myriad causes of bloating, and they are not mutually exclusive; you can have more than one at a time. Also and importantly, there are many other causes of bloating that go beyond the scope of this article, including Celiac Disease, Pancreatic Insufficiency, gynecological conditions, and cancer, to name a few. Is it important to speak with your doctor to rule out potentially serious causes of bloating. In addition, working in conjunction with a knowledgeable dietitian who is familiar with these issues can be very helpful. Remember that bloating is not something to be ignored and that there are solutions out there. Do not give up hope in finding relief.

The information provided in this article is intended for general use only and is not to be used in place of medical advice from a licensed health professional.