Gastric emptying in ethnic populations: possible relationship to development of diabetes and metabolic syndrome.

Direct as well as indirect evidence suggests that rapid gastric emptying may be occurring in Mexican Americans, American Indians, and other ethnic groups. Mexican Americans have been shown to have a more rapid rate of gastric emptying compared to non-Hispanic Whites after matching for weight, sex, and body mass index. Indirect evidence also suggests that American Indians and other ethnic groups may have an accelerated rate of gastric emptying of carbohydrate solutions. The rate of gastric emptying of carbohydrate-containing meals has been demonstrated to positively correlate with postprandial glucose levels (r=.58, P<.05). Accelerated absorption of carbohydrates following rapid gastric emptying in these ethnic groups could be a contributing factor to the increased risk of diabetes and metabolic syndrome. An abnormally accelerated gastric emptying of rapidly absorbed processed carbohydrates could be a genetic adaptation related to the paucity of rapidly absorbed carbohydrates in the native diets of certain ethnic populations. Further investigation is required to study gastric emptying in these different ethnic groups by using scintigraphy or other accurate methods. Ethnic populations with a high incidence of diabetes and impaired glucose tolerance might particularly benefit from therapeutic approaches with agents that slow gastric emptying.