Digestion is a complex process that requires coordination of physical and chemical factors. As soon as you place food in your mouth and begin to chew, you are mechanically breaking it down and exposing it to digestive enzymes, releasing nutrients that will eventually be absorbed into your bloodstream. This multifaceted activity continues throughout the length of your gastrointestinal tract. Disruption of any of a number of digestive processes can cause bloating and nausea after eating.
Food Intolerance
Intolerance to a particular food can be manifested by nausea, bloating, belching, excess gas and a change in your bowel habits. Lactose intolerance -- an inability to digest the sugar found in milk -- is relatively common, and many foods contain dairy products. You can develop lactose intolerance at any time, and you could be consuming lactose without even knowing it. Similarly, fatty foods, wheat, sugar and any number of foods can cause stomach upset for some people. Sometimes it helps to keep a food diary to zero in on specific items that cause problems for you.
Hiatus Hernia
A hiatus hernia is a protrusion of a portion of your stomach through the hiatus, which is the opening in your diaphragm leading from your chest cavity to your abdominal cavity. A hiatus hernia can cause an unusual cause of bloating and nausea immediately following a meal, but hiatus hernias are fairly common: At least 40 percent of patients getting chest X-rays are found to have one, according to "The Merck Manual of Diagnosis and Therapy." Food sometimes "sticks" in a hiatus hernia, leading to a sensation of fullness or bloating.
Gastroparesis
Gastroparesis, meaning "paralyzed stomach," is characterized by a reduction in your stomach's normal churning motion, which is needed to mix and liquefy your food. Reduced stomach motion frequently results in feelings of fullness, bloating or nausea after eating. Medications, surgery and diabetes are the most common causes of gastroparesis. A June 2008 review in "American Family Physician" reports that at least 10 percent of diabetics develop gastroparesis as a consequence of their disease.
Ulcers
Ulcers are erosions, or "sores," in the lining of your stomach or duodenum. About half of all ulcers in the United States are caused by infection with Helicobacter pylori, a spiral-shaped bacterium that tunnels into the mucous membrane of your stomach and incites an inflammatory response. Nonsteroidal anti-inflammatory medications, such as aspirin and ibuprofen, are also common causes of ulcers. While ulcers are classically associated with gnawing abdominal pain that is relieved by eating, other symptoms, such as bloating, nausea, heartburn and loss of appetite, can occur.
Pancreas and Gallbladder
Soon after you finish eating, your stomach begins releasing food into your duodenum, where it is mixed with enzymes secreted from your pancreas, and bile released from your gallbladder. Malfunction in either of these organs -- due to gallstones or chronic pancreatitis, for example -- results in alterations in the chemical makeup of the material in your duodenum, which triggers hormonal and neurologic reflexes that interrupt the further release of food from your stomach. You sense this digestive slowdown as bloating and nausea.
Recommendation
A variety of problems can lead to abdominal discomfort after a meal. Most of them are benign and easily diagnosed, while others may require extensive investigation. A change in your diet may be all that is necessary to relieve your symptoms, while some conditions require medical therapy. Rarely, more serious problems, such as cancer, can cause bloating and upset stomach, so any persistent abdominal complaint should prompt a visit to your doctor.
References
- "The Merck Manual of Diagnosis and Therapy, 18th Edition: Hiatus Hernia"; Mark H. Beers, M.D., Editor-in-Chief; 2006
- "American Family Physician"; Gastrointestinal Complications of Diabetes; A. Shakil, et al.; June 2008
- "American Family Physician"; Peptic Ulcer Disease; K. Ramakrishnan, R.C. Salinas; October 2007
