Intestinal absorption of sucrose.

Abstract

Abstract: Sucrose in synthetized in the green leaves of plants. With increasing economical status the sucrose from sugar cane and beets, like fat, supplies an increasing fraction of our food. Sucrose is easily metabolized and utilized. Too high consumption is, however, not desirable from nutritional point of view, since this highly refined product contains calories but no essential nutrients.The general concept is that animals (and humans) do not synthesize sucrose. A single report of a sucrose‐synthesizing patient needs confirmation from other sources before it can be accepted.The intestinal absorption of sucrose can only occur if the hydrolyzing enzyme, invertase (sucrase), is present in the mucosal cells. Acid hydrolysis in the stomach has been suggested, but does not occur. The intestinal invertase is an a‐glucosidase.In the human intestine invertase, as well as the other a‐glucosidases, is developed very early in fetal life — much earlier than lactase. In the animals studied so far, in contrast, intestinal invertase and other a‐glucosidases are weak until the weaning period, when lactase disappears and the a‐glucosidase develops. The reason for these species differences is yet unexplained.Human populations with low sucrose consumption have approximately equally high intestinal invertase activity as those in countries with high sucrose consumption. In Greenland Eskimos the adults have for a very long period of time (probably thousands of years) consumed nearly no carbohydrates at all. The average intestinal activity of invertase and the other a‐glucosidases in the Greenland Eskimos is nevertheless nearly the same as ours. Specific enzyme defects, which among us occur only as very rare cases of «inborn errors of metabolism« are, however, rather frequent in the Greenland Eskimos.