Most foods that contain carbohydrates can cause gas. By contrast, fats and proteins cause little gas.
Sugars- the sugars that cause gas are raffinose, lactose, fructose, and sorbitol:
- Raffinose: beans contain large amounts of this complex sugar. Smaller amounts are found in cabbage, Brussel sprouts, brocolit, asparagus, and other vegetables and whole grains.
- Lactose: lactose is the natural sugar in milk. It is also found in milk products such as cheese and ice cream. It can also be found in processed foods such as bread, cereal, and salad dressings. Many people, particularly those of Africa, Native American or Asian backgrounds, normally have low levels of the enzyme lactase needed to digest lactose after childhood. Also, as people age, their enzyme levels decrease. As a result, older people may experience increasing amounts of gas after eating foods containing lactose.
- Fructose: fructose is naturally present in onions, artichokes, pears and wheat. It is also used as a sweetener in some soft drinks and fruit drinks.
- Sorbitol: Sorbitol is a sugar found naturally in fruits, including apples, pears, peaches and prunes. It is also used as an artificial sweetener in many diabetic foods and sugar-free candies and gums.
Starches – most starches, including potatoes, corn, noodles and wheat produce gas as they break down in the large intestine. Rice is the only starch that does not cause gas.
Fiber – many foods contain soluble and insoluble fiber:
- Soluble fiber dissolves easily in water and takes on a soft, gel-like texture in the intestines. Soluble fiber is not broken down until it reaches the large intestine, where digestive causes gas. Foods that are particularly high in soluble fiber are: oats, beans, beets, psyllium (found in supplements and some cereals), apples, oranges, nectarines, peaches and carrots.
- Insoluble fibers, on the other hand, pass essentially unchanged through the intestines and produce little gas. Foods that are particularly high in insoluble fiber are: whole wheat bread, baked goods, whole grain breads, vegetables and fruits (especially the skins), peanuts and brown rice.
- The key is to get a good balance of these fibers. The recommended total fiber intake per day is 25-30 grams, depending on your sex, age and weight.
The problem with noxious flatus odor is that certain bacteria in the colon make sulfide gases in very tiny amounts, but it is enough to be noticeable. Foods containing moderate amounts of sulfate are: broccoli, cauliflower, brussel sprouts, cabbage, dates, dried apples, apricots, prunes, raisins, pasta and wheat.