tailieunhanh - The Encyclopedia Of Nutrition And Good Health - G

Bách khoa toàn thư - Dinh dưỡng và sức khỏe tốt - Vần G | G galactose A simple sugar found in the diet in milk sugar lactose . Galactose is a six-carbon sugar as is the more common glucose blood sugar . Unlike glucose however it does not occur by itself in foods. digestion of lactose by the intestinal enzyme lactase yields equal amounts of galactose and glucose. Before galactose can be used by the body for energy it must first be transformed into glucose by the liver. Certain people have a genetic susceptibility to galactose accumulation. See also CARBOHYDRATE METABOLISM GALACTOSEMIA. galactosemia A rare genetic disease due to an inability to degrade the sugar galactose normally. The most common defect is the inability to convert galactose to glucose an essential preliminary step for galactose to be used for energy production. Because galactose cannot be extensively degraded when the path to glucose is blocked it accumulates in the blood of galactosemic patients. This leads to severe mental retardation unless special galactose-free milk-free diets are administered shortly after birth. The prevalence of galactosemia is about one in 50 000. See also carbohydrate metabolism. gallbladder A dark green organ that concentrates and stores bile from the liver. Bile is a mixture of powerful emulsifiers needed to digest and absorb fat and oils and fat-soluble vitamins. When the intestine detects food and fat released by the stomach the intestine releases the hormone cholecystokinin into the bloodstream which causes the gallbladder to release bile into the duodenum the upper section of the small intestine. See also DIGESTIVE TRACT. gallstones Gravel-like deposits in the gallbladder in which bile is stored the gallbladder releases bile during meals to aid fat digestion and absorption. Many people consuming Western diets develop gallstones although the causes of gallstones are unknown. Risk factors include high-FAT Iow-fiber diets female gender obesity aging crohn s disease cystic fibrosis and alcoholic cirrhosis of the liver. The more