gastrointestinal disorders
Gas Related Complaints
Introduction
The gut contains<200 mL of gas, whereas daily gas expulsion averages 600 to 700 mL after consuming a standard diet plus 200 g of baked beans. About 75% of flatus is derived from colonic bacterial fermentation of ingested nutrients and endogenous glycoproteins. Gases include hydrogen (H2), methane (CH4), and carbon dioxide (CO2). Flatus odor correlates with hydrogen sulphide concentrations. Swallowed air (aerophagia) and diffusion from the blood into the lumen also contribute to intestinal gas. Gas diffuses between the lumen and the blood in a direction that depends on the difference in partial pressures. Thus, most nitrogen (N2) in the lumen originates from the bloodstream, and most hydrogen in the bloodstream originates from the lumen. 