Yogurt and fermented-then-pasteurized milk_ effects of short.pdf

Yogurt and fermented-then-pasteurized milk: effects of short- Am J C/in Nutr l989;49:823-7. Printed in USA. ? 1989 American Society for Clinical Nutrition 823 term and long-term ingestion on lactose absorption and mucosal lactase activity in lactase-deficient ,2 E Lerebours, C N’Djitovap Ndam, A Lavoine, MF He/lot, JMAntoine, and R Co/in Introduction ABSTRACT Lactase-deficient subjects absorb lactose in yogurt more effectively than bac- tose in other dairy products. However, as all previous studies were performed without a double- blind design and only after a single ingestion of the test product, the mechanism of this en- hanced absorption remains unclear. The aims of this double-blind study were 1) to evaluate lactose absorption after prolonged ingestion of yogurt and fermented-then-pasteurized milk (FPM) and 2) to assess the modification of the lactase activity ofthe duodenab mucosa. In 16 lactase-deficient subjects we confirmed that yogurt enhances lactose digestion, this beneficial effect being destroyed by pasteurization. Moreover, the long-term (8 d) ingestion of either yogurt or 1PM does not modify the results of hydrogen breath tests in comparison with a 24- h ingestion. The mucosal lactase (Dahlquist method) and fl-galactosidase (ONPG method) activities were not significantly modified by yogurt or FPM ingestion. These results suggest that in bactase-deficient subjects no adaptation occurs after eating yogurt or FPM and that the increased lactose absorption in yogurt must be mainly related to an intraluminal process. AmfClinNutr 1989;49:823-7. KEY WORDS Lactose digestion, yogurt, pasteurized yogurt, lactase, /3-gabactosidase Methods Primary bactase deficiency is predominant in most nonEuropean human populations (1). Previous human studies have shown that lactase-deficient subjects more effectively absorb lactose in yogurt than in milk or other fermented dairy products (2-4). Furthermore, pasteur- ization of yogurt eliminates the enhanced digestion of lactos