When she was 47 years old, Bonnie was referred to my clinic because of her symptoms of gas, bloating, loose stools, and lower abdominal pain. She said that the symptoms started approximately one year before our appointment and that she was somewhat embarrassed to even talk about them. Because of her excess gas, she was finding it hard to be around others, and she was worried that her symptoms represented something dangerous.
As I continued to ask Bonnie about the reasons for her visit, Bonnie admitted that she had read in a magazine that bloating is a sign of ovarian cancer. She is not usually a nervous or anxious person, but the magazine article made her worry about her symptoms. Bonnie told me that she typically had two to three somewhat urgent, loose stools each day and that these were always preceded by spasms and cramps in her lower abdomen. The stools were never bloody.
When her symptoms began, she had had a severe sinus infection and had taken several courses of antibiotics. Around the same time, she had started a new diet, because she had gained several pounds during the previous few years. None of Bonnie’s family members had a history of cancer or celiac disease, although both of her parents were lactose intolerant. On physical examination, I noted that her abdomen was slightly distended and tympanic (when I tapped on it, it sounded like a drum, which indicated that gas was present in her GI tract). Her internist had ordered a complete blood count (CBC) and celiac blood tests, and these were both normal. Bonnie’s gynecologist had performed a careful examination and ordered a pelvic ultrasound just to be on the safe side; both were normal.
When I asked Bonnie about her diet, she told me that she drank several glasses of low-fat milk each day (to provide calcium and vitamin D) and that she had a dish of ice cream every night. She had recently decided to become a vegetarian and she consumed large amounts of fresh fruits, fresh vegetables, beans, and whole-grain foods. She didn’t like the taste of coffee, so to help stay alert at work she often drank three to four cans of a caffeinated cola drink each day. Bonnie also started off each morning with a large glass of orange juice, and when she went to the gym, she often drank a commercial sports drink afterward to rehydrate.
At the suggestion of a friend, Bonnie had tried digestive enzymes to help with her symptoms, but these did not help. Before work meetings, she would sometimes use an over-the-counter product such as Gas-X or charcoal capsules, but she was not sure that these helped either. She wondered what the cause of her problem was and what could be done to help.
Bonnie’s case is not unusual. Although it is ideal to have one simple explanation for the cause of someone’s symptoms, I knew that it was likely that Bonnie’s symptoms had developed for several reasons. One, she had been treated with several courses of antibiotics just before the onset of her symptoms. Her normal gut flora was probably changed by the antibiotics, which can create problems with gas and bloating. Two, Bonnie was consuming a fairly large quantity of dairy products each day. It was probable that she was lactose intolerant and that the undigested milk sugars were fermenting when they reached the colon, creating excess gas and bloating. Three, Bonnie was consuming a large amount of fructose each day in the form of orange juice, commercial sodas, and sports drinks (the latter two are usually made with high-fructose corn syrup). Many people who have IBS are fructose intolerant. When fructose is not absorbed in the upper GI tract, it breaks down in the colon and causes gas. Four, Bonnie had become a vegetarian one year ago, around the time she started noticing symptoms. She was trying to eat very healthfully by avoiding fats and red meat. However, she had substantially increased her intake of beans, fruits, and vegetables. All of these products contain insoluble fiber, which cannot be digested and ends up being fermented in the colon. In addition, dried and canned beans (red beans, black beans, garbanzo beans, lentils, and kidney beans) contain complex carbohydrates, and most individuals do not have the enzyme needed to break these down completely in the GI tract.
After we discussed her treatment options, Bonnie said that she did not want to try probiotics, antibiotics, or other medications to treat her symptoms. Rather, she wanted to try to identify the cause of her symptoms. We both agreed that it was likely that dietary factors were playing a role. I told Bonnie that she could go on a strict elimination diet (see Chapter 10) to get rid of most of the troublesome substances all at once, or she could try to eliminate the worst offenders. She chose the latter, and shortly afterward, Bonnie stopped her intake of all foods and liquids with dairy, instead substituting Lactaid, rice, soy, or almond milk products. Bonnie also stopped drinking commercial sodas and orange juice (which contain high-fructose corn syrup and natural fructose, respectively) and substituted water or unsweetened green tea. Finally, she eliminated all dried and canned beans, and she limited her fiber intake to no more than 30 gm per day (which is still above the recommended daily dose of 25 gm).
When Bonnie modified her diet in these ways, her symptoms essentially resolved. She still had occasional spasms and cramps with some urgency when she had a bowel movement, but she said that these symptoms were tolerable. She no longer had problems with bloating and gas. In addition, by cutting out the juice and soft drinks, Bonnie lost two pounds every month, until she was back to her previous weight.
Treating the symptoms of gas and bloating can be one of the most difficult tasks for gastroenterologists. Everybody makes gas in the intestinal tract; on average, a person makes approximately 750 to 1,000 ml of gas each day. Not surprisingly, most gas forms after the ingestion of food. Foods that are high in insoluble fiber are more likely to create gas than food products that consist of protein and simple carbohydrates.
Many different gases are present in the GI tract. The five most common are nitrogen, oxygen, hydrogen, carbon dioxide, and methane. Nearly all of the nitrogen and oxygen within the upper GI tract comes from swallowed air. Carbon dioxide in the GI tract comes from swallowed air and from carbonated beverages. It is also a side product of the neutralization of acids and alkalis (bases) and of bacterial fermentation of undigested foodstuffs. Hydrogen gas is also produced as a result of bacterial fermentation, as is methane (although much less common).
Most intestinal gas forms in the colon due to the action of the colonic microflora, which consist of the approximately five hundred to one thousand different species of bacteria that normally reside within the colon. There are more live bacterial cells in the colon than there are live nonbacterial cells in the entire rest of the human body; if collected and weighed, the normal bacteria in the colon would amount to 4 to 5 pounds. These bacteria serve a variety of functions—they help protect the colon and they aid in the immune system of the gut. One of their major roles is to complete the digestion of unabsorbed foodstuffs. When that occurs, gas is produced.
Bloating is defined as a sense of gassiness or a sense of being distended. Distention is when the abdomen is clearly swollen and larger in size than normal, all due to the presence of excess intestinal gas. Some people who have irritable bowel syndrome feel gassy and bloated, but their abdomens are never distended; other people who have IBS may feel gassy and bloated and also develop distention. Individuals who have bloating and distention usually feel better in the morning, because there is little food in the GI tract at the beginning of the day and thus less gas can be formed. Predictably, as the day goes on and people eat and drink, gas forms, leading to sensations of being gassy and bloated and the physical manifestation of distention.
Bloating is one of the most difficult gastrointestinal conditions to treat. Some treatment options for IBS actually worsen bloating (for example, products with excess fiber). Dietary modification, rather than medication, is often the best treatment for people who have bloating (see Chapter 15). Probiotics and antibiotics may improve symptoms of bloating in some individuals. Unfortunately, medications designed specifically to alleviate gassiness and bloating are usually ineffective in most patients. Trial and error may be the only way to find which medication, if any, may improve your symptoms.
Some of the most commonly used medications for bloating are available over the counter. See Table 19.1 for a list of medications used to treat bloating.
Some studies have shown that probiotics, live bacterial supplements, improve the health and balance of native intestinal microflora. Probiotics are found in yogurt or can be taken in capsule form. The theory behind the use of probiotics for bloating is that excess gas may develop from an imbalance of the normal bacteria in the GI tract or from the lack of a specific bacterium and that probiotics may rebalance or replace these bacteria.
Research studies on the use of probiotics to treat bloating have shown mixed results. In two studies of people who had IBS and diarrhea, a probiotic (VSL#3) containing eight different strains of three bacterial species (Streptococcus, Bifidobacterium, and Lactobacilli) improved symptoms of abdominal bloating. Lactobacillus plantarum 299V was found to improve bloating and distention in only one of three studies that were performed. Another study found that Lactobacillus GG did not improve symptoms in a group of 24 patients who had IBS. Bifidobacterium infantis (sold as the probiotic Align) has shown some ability to improve symptoms of bloating and abdominal discomfort in people who have IBS and diarrhea. Flora-Q is another probiotic being heavily marketed to treat a variety of gastrointestinal disorders, but there are no large prospective studies evaluating its efficacy in individuals who have IBS.
Some researchers and physicians strongly believe that bloating is due to the presence of too much bacteria in the intestinal tract (see Chapter 11) and that antibiotic therapy should therefore improve symptoms of bloating by destroying the overabundant bacteria. Indeed, some health care providers routinely use antibiotics to treat symptoms of bloating. But bacterial overgrowth of the GI tract is an uncommon condition, and in most cases it does not cause bloating. I do not recommend antibiotics as a first-line treatment for patients who have bloating because antibiotics can be expensive and entail risks with routine use, such as adverse reactions, medication interactions, the possibility of developing a severe infection of the colon (C. difficile colitis), and the potential to develop resistance to the antibiotic. Antibiotic resistance can be very dangerous if a person develops a severe infection and cannot be treated with the necessary antibiotic because he or she no longer responds to it. When I am concerned about bacterial overgrowth in patients who have persistent bloating and have failed to respond to dietary interventions (see Chapter 15) as well as trials of over-the-counter medications and probiotics, I schedule a hydrogen breath test (see Chapter 11). If this test is positive, I treat the patient with antibiotics.
Table 19.1. Medications Used to Treat Bloating
Antiflatulents Simethicone (Mylicon, Gas-X, Phazyme) Charcoal Enzyme replacements Smooth-muscle antispasmodics Hyoscyamine (Levsin) Dicyclomine (Bentyl) Librax (chlordiazepoxide + clidinium) Donnatal (phenobarbital + atropine + hyoscyamine + scopolamine) 5-HT3 antagonists (that is, Alosetron) Chloride channel activators (for example, lubiprostone) Guanylate cyclase C activators (for example, linaclotide) Probiotics Antibiotics |
Over-the-counter products like Gas-X and Phazyme contain simethicone, which breaks up large gas bubbles into smaller ones in the stomach. Smaller bubbles are easier to belch or burp up when gas is in the stomach. However, simethicone rarely helps when gas is in the small intestine or colon, and that is the major problem for most people who have IBS.
Activated charcoal is used in many different filtering systems to clean water or air in kitchens and bathrooms. It is also sold in capsule form to be swallowed, because it can absorb some intestinal gas and thus improve its odor. Some patients find that charcoal improves their symptoms of bloating to a small degree. Charcoal capsules generally need to be taken before each meal. They can darken the stool (a worrying side effect for some patients because very dark stool can be a sign of internal bleeding).
Some people develop bloating because they do not have enough of the right enzymes to break down specific food products properly. For example, people who have lactose intolerance do not have enough of the enzyme lactase so, to avoid GI problems when they eat milk products, they may need to take additional lactase (see Chapter 15 for more information). Lactose intolerance is present in at least 30 percent of people who have IBS.
Fructose intolerance is another enzyme deficiency that is fairly common in people who have IBS (one study reported that up to 50 percent of people who have IBS and diarrhea are fructose intolerant) and that can lead to symptoms of gas and bloating. Unfortunately, there is no medication to treat fructose deficiency (or the other enzyme deficiencies that may contribute to the development of gas and bloating).
The most popular over-the-counter enzyme replacement is Beano. This product contains galactosidase, an enzyme that helps break down complex sugars, including raffinose and stachyose. These two sugars are found in many of the cruciferous vegetables (broccoli, cauliflower, cabbage) and legumes (beans, peas) that often cause intestinal gas. Available in both tablet and liquid forms, Beano is typically taken before any meal that contains food that may cause gas (for example, beans). Beano does not break down fiber, however, which is a major source of gas production in the GI tract.
Other enzyme replacements are available over the counter in health food stores or may be prescribed by a physician. These replacements include pancreatic enzymes, such as lipase, protease, or amylase (Creon, Pancrease, and Viokase). The normal human pancreas makes more than enough of the enzymes needed to break down ingested foods and liquids and to promote the absorption of all necessary nutrients. Enzyme replacements are beneficial for people whose pancreas has been injured and cannot produce enough enzymes (a condition called pancreatic insufficiency). However, there is no evidence that people who have IBS have a higher-than-normal incidence of pancreatic insufficiency.
Overall, I would not recommend enzyme replacements as routine treatment for the bloating experienced with IBS. These medications have never been scientifically evaluated in a group of patients who have IBS.
The theory behind the use of antispasmodic medications (described in Chapter 18) to treat gas and bloating is that spasms of the colon or small intestine can trap gas, thereby leading to sensations of bloating. By relaxing the smooth muscle of the GI tract, the spasms are resolved and the gas can be expelled more easily. Some patients taking antispasmodics do report some relief of gas and bloating, but most do not. As a group, smooth-muscle antispasmodics are useful for relieving abdominal pain, but they cannot be recommended specifically for relief of gas and bloating.
As mentioned throughout this book, many people who have IBS experience a variety of coexisting symptoms. When some patients who have IBS and constipation are treated with lubiprostone (Amitiza) or linaclotide, they also note a significant improvement in their symptoms of gas and bloating. Other people who have IBS and diarrhea report an improvement in bloating and gas symptoms when treated with alosetron (Lotronex). See Chapters 16 and 17 for more information on the use of these prescription medications.
• Bloating is a common symptom in people who have IBS. In fact, it is the second most common reason individuals who have IBS seek medical attention (abdominal pain is the number one reason).
• Bloating is a sensation of gassiness; distention is the physical manifestation of excess intestinal gas (or gas that is difficult to eliminate).
• Dietary factors often play a role in symptoms of gas and bloating. Lactose intolerance, fructose intolerance, and insoluble fiber are the worst offenders.
• Probiotics have been shown to improve symptoms of gas and bloating for many people who have IBS.
• Antibiotics can be safely used to treat symptoms of gas and bloating; a breath hydrogen test is useful to help guide treatment.
• Although frequently used and quite safe, over-the-counter agents that are advertised to decrease problems with gas and bloating are rarely effective.