Influence of Caffeine-containing Beverages on the Growth, Food Utilization and Plasma Lipids of the Rat

Abstract

It has been suggested that coffee-drinking may be a factor in the causation of cardiovascular disease, and tea drinking a factor in its prevention. In the present study, freeze-dried tea, decaffeinated coffee, coffee and pure caffeine were fed to rats, for 54 days, in a starch-based diet devoid of recognized atherogenic agents. None of the dietary supplements affected growth rate, the efficiency of food conversion or the weights of the organs. Changes produced in the plasma lipid values were proportional to the caffeine content of the diets. With increasing intake of caffeine, plasma cholesterol and phospholipid concentrations rose, while the triglyceride concentration fell. Feeding sucrose affected the plasma lipids in the opposite direction; triglycerides were increased whereas cholesterol and phospholipids were unaltered. This difference in response is attributed to a difference in the rate of lipid synthesis in the liver. The activity of pyruvate kinase, which was used as an index of lipogenesis, was unaffected by coffee, but was doubled by the substitution of sucrose for starch in the diet. Results are discussed briefly in relation to current views on the role of plasma lipids in atherogenesis.