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Digestive Health Special Report

You've Got Gas and What You Can Do About It

Johns Hopkins Health Alerts Digestive Health Gas, Burping, Flatulence

When are flatulence, burping, and belching the signs of a serious problem? Sergey V. Kantsevoy, M.D. , Assistant Professor of Medicine at Johns Hopkins, provides the answers.

Some people find gas -- and the belching (burping), flatulence, and stomach bloating that go with it -- an embarrassing subject, but it’s actually a normal occurrence. In fact, the human body produces between one and four pints of gas a day, which it releases via the mouth or the rectum about 14 times a day.

Where Does Gas Come From?

Gas gets into the digestive tract when you swallow air (oxygen) and during the normal metabolism of carbohydrates.

Swallowed air. You swallow small amounts of air when you’re eating and drinking, and you take in greater amounts when you eat or drink rapidly, don’t chew your food completely, suck on hard candies, chew gum, smoke cigarettes, or wear loose dentures. Most swallowed air escapes from the stomach via the mouth when you burp, or belch. The rest of the air travels to the small intestine; some of it is absorbed there, while the remainder moves into the large intestine and then is released through the rectum.

Undigested carbohydrates. Gas is also produced in the digestive tract during digestion. Your body is not able to adequately digest some carbohydrates (sugars, starches, and fiber) in the small intestine, which is where the food you eat is normally metabolized and absorbed. Instead of being absorbed, these undigested carbohydrates go into the large intestine (the colon), where they are broken down by bacteria that reside there. In the process, the bacteria -- which are harmless -- produce the odorless gases hydrogen, carbon dioxide, and sometimes methane. The bacteria may also release the malodorous gas, sulfur. Like stool, the gases are then passed out of the body through the rectum. During the digestive process, the gases that are formed may cause stomach bloating or even discomfort. Stomach bloating can also be due to weak abdominal muscles. This is the case when bloating worsens as the day goes on and gets better when you lie down.

Several types of carbohydrate-containing foods are notorious for causing gas. These foods include:

  • vegetables such as artichokes, asparagus, broccoli, Brussels sprouts, cabbage, corn, onions, and potatoes
  • fruits such as apples, peaches, and pears
  • beans (especially baked beans)
  • carbonated beverages
  • wheat products such as pasta and whole grain breads and cereals.

Many people also develop gas after consuming milk products that contain the sugar lactose. This is because they make insufficient amounts of the enzyme lactase, which the body needs to digest lactose. As you age, your lactase level naturally declines. Fats and proteins rarely cause gas.

When Gas-related Symptoms Require a Doctor’s Attention

Most cases of gas are normal. But an unusual amount of gas (more than 23 episodes of flatulence or belching/burping a day on a regular basis) or symptoms like abdominal bloating and discomfort may indicate lactose intolerance or a more serious disorder. If this is the case, you should make an appointment with your doctor.

Chronic belching can be a sign of gastroesophageal reflux disease (GERD) or a peptic ulcer, while stomach bloating can be a sign of irritable bowel syndrome, gastroparesis (delayed emptying of the stomach), or Crohn’s disease. People who’ve had hernias in their digestive tract, have undergone many surgeries to their digestive tract, or have scar tissue in their digestive tract may also have problems with bloating and pain. From a review of your diet and the number of times you pass gas a day, a doctor can often determine the cause of your symptoms. If a diagnosis is not obvious (for example, excess gas is not related to lactose intolerance or consumption of a large amount of gas-causing foods), your doctor may suggest you have a sigmoidoscopy, colonoscopy, or upper GI series to determine if you have a serious disorder.

Here are some easy steps you can take to reduce the amount of gas you pass:

  • Eat and drink slowly and chew your food well. This will help reduce the amount of air you take in when you swallow.
  • If you’re prone to gas, avoid chewing on gum and sucking on hard candies.
  • If you have dentures, check with your dentist to make sure they fit properly.
  • Identify the foods that cause gas for you. You probably won’t have to avoid these foods altogether. Instead, you’ll just have to reduce the amounts you currently eat. So experiment to see how much of these gas-causing foods your body can handle before gas becomes a problem.
  • If you’re adding fiber (more fruits, vegetables, and whole grains) to your diet, do so slowly so your body can adjust without producing excess gas.
  • If you experience gas after eating dairy products, you can take lactase supplements (Lactaid, Lactrase) before eating to reduce how much gas your body produces. You can also buy lactose-reduced milk and other products such as Lactaid and Dairy Ease.
  • Try the over-the-counter digestive aid, Beano, which contains an enzyme that helps you to digest the sugar in beans and vegetables. You can add Beano to your food as a liquid or take tablets before eating.
  • Take a nonprescription antiflatulent with simethicone, such as Gas-X or Mylanta Gas Relief. Simethicone works by breaking up gas bubbles in your digestive tract.
  • Engage in regular physical activity (30 minutes a day on most, and preferably all, days of the week). Doing so will help speed the clearance of excess gas.
  • Strengthen your abdominal muscles by pulling in your stomach several times a day, regularly doing exercises such as sit-ups, or wearing a support garment. Strengthening your abdominal muscles will also help decrease bloating.

  • For more Digestive Health articles, please visit the Digestive Health Topic Page

    Posted in Digestive Health on January 10, 2007

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