Upper gas, what we call belching or burping, generally consists of swallowed air, which is largely nitrogen. This gas reflects the air around us, so burping rarely smells bad. However, flatulence, or passing gas from the rectum, is determined by the food you eat and the activity of the bacteria in your colon. When undigested food reaches the large intestine, it is broken down by the bacteria that are normally found there into hydrogen, carbon dioxide and, in one-third of individuals, methane. It is not clearly understood why some people produce methane and others do not, and it may have something to do with the balance of different bacteria in the colon.
Causes of Gas
Dairy Products and Lactose Intolerance
"My friend told me that dairy products cause gas, so I cut these out of my diet but I still get very bloated."
Dairy products contain the sugar lactose, and in some people lactose can produce gas. Lactose is found not only in milk, but in cheese and ice cream as well. It is very important to read labels and look not only for lactose, but for 'casein' and 'whey.' These ingredients also contain milk sugars, and can be found in cereals, salad dressings and processed foods.
Lactose intolerance is a deficiency of the enzyme 'lactase' in the small intestine, the enzyme required to digest lactose. This decrease occurs as a result of ‘growing up’, or growing older. Those of African, Native American, Asian or Ashkenazi Jewish descent, may have even greater propensity for lactose intolerance. Unfortunately lactose is not the only sugar that causes gas. The other sugars or carbohydrates that cause gas are raffinose, sorbitol and fructose.
