Eating a greasy hamburger could cause an upset stomach in almost anyone. But for the one in five people who have irritable bowel syndrome, or IBS, certain foods like fatty burgers can cause more than a little stomach upset. People with IBS experience painful bloating, abdominal discomfort, stomach cramps, diarrhea, and constipation.
IBS: What's It All About?
When you have IBS, you have an overly sensitive colon, or large intestine. Doctors don’t know why, but people with IBS seem to have trouble with the movement in their colon. In some cases, contents in the colon move too fast and the colon doesn’t absorb enough fluid, which causes diarrhea (called IBS-D). In other cases, the contents don’t move fast enough and too much fluid is absorbed, causing constipation (called IBS-C).
For this reason, people either experience chronic diarrhea or chronic constipation, says Steven Field, MD, a gastroenterologist and clinical assistant professor of medicine at New York University School of Medicine in New York City. In some cases, symptoms alternate between diarrhea and constipation, he says.
IBS: What Triggers It
Two things may trigger IBS: certain foods and stress. “Fried and greasy foods tend to bother people with IBS,” Dr. Field says. There’s also a high incidence of lactose intolerance among people with IBS, he notes, where there is a difficulty breaking down milk sugar.
Field recommends that people with IBS keep a food journal for about two weeks to pinpoint the foods that cause symptoms. “When you review a journal, certain patterns emerge that weren’t obvious from the beginning,” he says.
Stress can also trigger IBS symptoms because your colon is connected to your brain through nerves. When you feel nervous “butterflies,” it’s the nerves in your colon responding to stress, but if you have IBS your colon may have a stronger, more painful response to stress. “Many patients note that their symptoms are worse when they’re under stress,” Field says. In fact, a significant number of patients with IBS have symptoms of depression or anxiety.
IBS: Possible Causes
Doctors don’t know why some people have IBS, but one theory has to do with the neurotransmitter serotonin. “Serotonin is best known as a chemical in the brain that helps regulate mood, but surprisingly, only about 5 percent of the body’s serotonin is found in the brain,” Field says. Close to 95 percent of it is located in the cells of the gut wall, where it regulates contraction, the movement of the bowel, and the secretion of fluid in the bowel.
When there’s an abnormal amount of serotonin in the gut, or if there’s an abnormality in the function of serotonin, it can lead to abdominal pain, cramping, and changes in bowel habits, especially loose stools, Field says. That may explain why antidepressants — many of which work on serotonin — can help relieve IBS symptoms, Field says.
Another theory is that IBS is caused by a bacterial overgrowth in the gut. Researchers found that some people with IBS have gotten better when they’re treated with antibiotics, according to Field.
IBS: Who Gets It
IBS can hit at any age, but it’s more common between the ages of 18 and 35. That could be because people in that age group typically go through a lot of change — such as going to college, getting a job, getting married, and having kids — and stress can bring on the symptoms of IBS. It is also more commonly seen in women.
If you’re in your 40s, 50s, or 60s and experience IBS symptoms, your doctor will want to rule out a more serious disease such as diverticulosis or colon cancer before giving you a diagnosis of IBS, Field says.
Be sure to tell your doctor about these red flags that may indicate a more serious problem: blood in your stool, fevers, weight loss, or symptoms that awaken you from sleep. “Your doctor will also be checking your blood for findings like anemia or other abnormalities, which may indicate another diagnosis,” Field says.
The good news: Although IBS can be extremely uncomfortable, it doesn’t lead to cancer or other serious diseases. When you keep a food journal to learn which foods trigger your symptoms and limit the amount of stress in your life, you may find that your symptoms disappear.