The main source of gas, though, is the normal bacterial fermentation in our colon of undigested sugars. Dairy products are a
leading cause of excessive flatulence, due to poor digestion of the milk sugar lactose, though even people who are lactose tolerant may
suffer from dairy. One of the most flatulent patients ever reported in the medical literature was effectively cured once dairy products were removed from his diet. The
case, reported in the
New England Journal of Medicine and submitted to the Guinness Book of World Records, involved a guy who, after consuming dairy, experienced “70 passages in one four-hour period.” Cutting the cheese, indeed.
Other poorly digested sugars include sorbitol and xylitol in sugar-free candies. The fizziness in soda is carbon dioxide, which gets absorbed by our gut, but the high fructose in the soda’s corn syrup may be another
culprit. Cruciferous vegetables may also
contribute (kale-force winds?). Some grains can do it—the word pumpernickel
stems from Middle German and means, roughly, “goblin that breaks wind.”