In Reply.—We appreciated the comments of Vellas et al. First, regarding the age of our subjects in enteral hyperalimentation: At 64 ±2 years, with a history of heavy alcohol and smoking, with only 74% of ideal body weight, these were not "too young," but biologically very old. Their small intestine was not affected with malignancy, so we find it difficult to understand why these subjects were "very different than older patients previously described."
Second, regarding the capacity of the aging gut to absorb fat. None of the authors quoted by Vellas et al showed an age-related decrease in the functions affecting fat digestion or absorption. On the contrary, Greenberg et al reported increased pancreatic lipase in aging rats. In Holt's study the cellularity of intestinal villi responded to starvation and refeeding similarly in young and old rats. Jejunal thymidine kinase, which is related to DNA synthetic activity and mucosal