Beneficial Effects of Collagen Hydrolysate: A Review on Recent Developments

Collagen is the main structural protein of the different connective tissues, such as skin, bone, cartilage and tendons, and comprises about one-third of total proteins in mammals. Collagen extracted from collagen-rich materials with hot water is known as gelatin. The common materials used for extracting gelatin include pig skin (46%), bovine hide (29.4%), bones (23.1%) and other sources (1.5%) [1]. However, fish gelatin has received great attention in recent years due to the religions, cultures and health concerns. The further enzymatic hydrolysis of gelatin results in collagen hydrolysate (CH). CH has long been used in pharmaceuticals and foods in many countries and regions, such as United States, Europe, China and Japan. Approved as Generally Recognized As Safe (GRAS), the safety of CH has been affirmed by the Food and Drug Administration (FDA) Center for Food Safety and Nutrition. The bioavailability and absorption of CH have also been widely studied. It has been reported that CH is more easily absorbed and has higher bioavailability than gelatin [2,3]. Besides free amino acids, small peptides especially dipeptide and tripeptide are also absorbed into body by peptide transporter 1 (PepT1) [4]. To date, more than30 peptides (mainly dipeptides and tripeptides) have been identified in blood after gelatin and CH intake, and Pro-Hyp is the most abundant collagen-derived peptide [5-7]. These peptides may exert various beneficial effects on body health as previous studies reported [8-9]. In this paper, we will mainly focus on the recent findings (year 2010-2017) regarding the beneficial effects of CH in animal experiments and clinical trials (Figure 1). The possible mechanisms underlying CH will also be briefly discussed.