Over the weekend, I noticed an interesting question in a column by The People’s Pharmacy’s Joe and Teresa Graedon that addressed the topic of flatulence due to diet. The person who wrote in said that her son is a vegetarian who eats a lot of beans and dairy for protein, as well as lots of vegetables. He especially eats a lot of broccoli, Brussels sprouts, cabbage and carrots. “He is so flatulent, we can hardly stand it,” the mother wrote.
Smelly gas is one thing, but as I did a little research, there can be other outcomes from gas, such as misdiagnosis of other health issues. For instance, gas in the intestines can cause severe pain for some people, leading to misdiagnosis for a more severe condition. When pain from gas is on the left side of the colon, doctors can confuse it with heart disease. When the pain is on the right side, doctors may suspect gallstones or appendicitis.
So what is gas? Why does it occur? Why does it become smelly? What foods cause it? And how can you avoid it?
Well, actually you can’t avoid gas, per say. According to the U.S. Department of Health and Human Services’ National Digestive Diseases Information Clearinghouse (NDDIC), everybody has gas. In fact, most people create between 1-4 pints a day and pass gas approximately 14 times each day.
Gas in the digestive tract comes either from swallowed air or the normal breakdown of foods by natural good bacteria in the colon. This can lead to belching and flatulence. The gas primarily consists of odorless vapors, including oxygen, carbon dioxide, nitrogen, hydrogen and methane. However, the unpleasant odor of flatulence, which occurs when gas passes through the rectum, is caused by bacteria in the large intestine that releases small amounts of gases that contain sulphur.
Since this is a diet and exercise site, let’s focus on undigested foods. NDDIC reports that the body doesn’t digest and absorb some sugars, starches and fiber in many foods in the small intestine due to a shortage of specific enzymes that assist with digestion. These foods then move to the large intestine to be broken down by natural bacteria. The breakdown results in hydrogen, carbon dioxide, and – in a third of the population -- methane. All of these gases eventually exit through the rectum. The NDDIC notes that common bacteria in the large intestine are believed to destroy the hydrogen that is created by other bacteria. “The balance of the two types of bacteria may explain why some people have more gas than others,” the clearinghouse website states.
Researchers also have found that specific foods do not universally cause gas in everyone. However, carbohydrates have been found to have a propensity to cause gas more often than fats and protein. In fact, flatulence is believed to be caused by malabsorption of carbohydrates. Three groups seem to be the culprits:
- Sugars, including raffinose (found in beans, cabbage, brussels sprouts, broccoli, asparagus, other vegetables and whole grains), lactose (found in milk, cheese, ice cream, bread, cereal and salad dressing), fructose (found in onions, artichokes, pears, wheat and as a sweeter in some soft drinks and fruit drinks), and sorbitol (found in fruits such as apples, pears, peaches and prunes as well as in artificial sweeteners used in some soft drinks and fruit drinks).
- Starches, which produce gas when broken down in the large intestine. Interestingly, most starches – including potatoes, corn, pasta and wheat – produce gas; however, rice does not.
- Fiber – Soluble fiber, which dissolves easily in water and becomes a soft, gel-like texture in the intestines, can cause gas. Foods with soluble fiber include oat bran, beans, peas and most fruits. However, insoluble fiber, found in wheat brain and some vegetables, passes through the digestive tract unchanged and produces little gas.
So how can you control gas? Health professional suggest an initial review of the diet and amount of gas passed to determine if specific foods are related to the symptoms. If specific foods are found, people may be asked to lower consumption of this food. In addition, over-the counter supplements have digestive enzymes that can help with the digestion of carbohydrates. Doctors also may prescribe medications to reduce symptoms for people with digestive disorders.