Angiotensin converting enzyme inhibitory peptides from a lactotripeptide-enriched milk beverage are absorbed intact into the circulation

Abstract

Food products containing angiotensin converting enzyme (ACE) inhibitory peptides reportedly play a role in treatment of mild hypertension. The aim of this placebo-controlled crossover study was to assess the bioavailability of Ile-Pro-Pro and 7 other ACE-inhibiting peptides present in a lactotripeptide (LTP)-enriched yogurt beverage and whether meal intake affects Ile-Pro-Pro bioavailability. Six male and female subjects randomly consumed an LTP-enriched yogurt beverage or a placebo in the fasted state and an LTP-enriched yogurt beverage in the fed or fasted state. The area under the curve (AUC) of Ile-Pro-Pro after the LTP treatment in the fasted state was 2.1-fold of that after the placebo treatment (P < 0.001). The maximum peptide plasma concentration (Cmax) value was greater after consumption of the LTP-enriched beverage (897 ± 157 pmol/L) than after the placebo treatment (555 ± 0.09 pmol/L; P < 0.001) with a greater time after ingestion when reaching Cmax (Tmax) in the placebo treatment. Plasma concentrations of the peptides Leu-Trp, Phe-Tyr, Ile-Tyr, and Leu-Pro-Pro increased compared with baseline (P < 0.05) in the LTP-enriched and placebo treatment when consumed in the fasted state. However, ΔCmax values differed significantly between the placebo and LTP-enriched treatment only for Leu-Pro-Pro. Meal intake affected Ile-Pro-Pro concentrations. When the beverage was consumed after a meal, the AUC of Ile-Pro-Pro was 1.3-fold (P < 0.05) of the AUC derived from premeal intake. This was due to an increase in the plasma elimination half-life (P < 0.05); Cmax and Tmax were not affected by meal intake. In summary, this is the first demonstration, to our knowledge, that the tripeptide Ile-Pro-Pro selectively escapes from intestinal degradation and reaches the circulation undegraded. © 2007 American Society for Nutrition.