High blood pressure is considered as a significant health problem worldwide. In addition to numerous preventive and therapeutic drug treatments, important advances have been achieved in the identification of dietary compounds that may contribute to cardiovascular health. Among these compounds, peptides with antihypertensive properties received special attention in the past 15 years. Although milk proteins are still the main source of antihypertensive peptides, recently a remarkable increase has been noticed in the report of antihypertensive peptides released from other dietary sources. Most of these peptides have demonstrated their properties by in vitro assays. However, the evidence for their beneficial antihypertensive effects has to be based on animal experiments and clinical trials. This paper reviews the current data of the blood pressure-lowering activity of food-derived peptides demonstrated in vivo (animal models and humans). Other aspects, such as the mechanism of action and bioavailability of these peptides which play a key role in their antihypertensive effects are also summarized in this review.

The human colon adenocarcinoma cell line HT29, is not only used to study the biology of human colon cancers, but it is receiving special interest in studies focused on food digestion and bioavailability due to the ability to express characteristics of mature intestinal cells. In the differentiated phenotype, they are able to form a monolayer with tight junctions between cells and a typical apical brush border. In addition, these differentiated cells express brush-border-associated hydrolases typical of the small intestine although the enzymatic activity is lower than that found in vivo. Although they represent a valuable model due to their similarities with enterocytes of the small intestine, their limitations and the relevance to the in vivo situation are also considered in this chapter. The application of this cell line to transport studies of drugs and food compounds is illustrated, especially when the effect of the mucus layer is considered or used as co-culture in combination with Caco-2 cells. They have also been frequently used to study the intestinal immune response to bacterial infection, and microorganism survival, adhesion or invasion. Finally, the use of these cells to evaluate the effect of several food compounds and mucin secretion is summarized.