Exploring the "MEAT FACTOR": enhancement of non-heme iron bioavailability

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Certain components in muscle tissue can enhance non-heme-iron absorption (Fe) – this phenomenon is called the “meat factor”. Iron deficiency anemia is a common nutritional disorder where 20% to 50% of the world’s population does not have adequate dietary iron. Seniors in Canada have a higher prevalence of anemia compared to younger people, and interestingly, iron deficiencies in the developed world are commonly not an issue of dietary iron alone, but rather, represent an absorption problem. We are interested in exploring the meat factor to create foods that can help people absorb Fe better. One meat factor molecule is a carbohydrate called glycosaminoglycans (GAGs), found in all the tissues associated with meat. GAGs are made of unbranched chains of sugars that are attached to proteins. They are not only found in meat, but also in connective tissue like cartilage, tendon, and skin, and represent an undervalued and underutilized by-product of the meat processing industry. GAGs have been shown clinically to help with joint problems like osteoarthritis (e.g. Chondroitin sulfate) when taken as an oral supplement, but more research is needed to show how GAGs can be used in other applications like improving Fe absorption. We are also adding certain sugars onto connective tissue collagen peptides to increase Fe bioavailability. The main goal of our research program is to better understand the molecules responsible for increasing Fe absorption. Parallel research projects will be coordinated representing specific and interrelated objectives. Specific objectives are: i) To understand the chemistry and mechanism of how GAGs from different tissue types, such as skin, cartilage, and meat, promote Fe bioavailability; ii) To investigate the role of specific meat collagen peptides on Fe bioavailability; iii) To add sugars to collagen peptides, both enzymatically and chemically, to determine their subsequent effects on Fe bioavailability; iv) To develop the potential of connective tissue culturing techniques to produce bioactive GAGs for future potential markets. The first project evaluates the ability of GAGs from different tissues to increase the bioavailability of Fe. GAGs are extracted using methods optimized in our laboratory, and tested using a “Caco-2” cell culture screening system. Iron transporter expression and the production of an iron storage protein, ferritin, within Caco-2 cells, are key factors we monitor to evaluate Fe bioavailability. This system allows us to do preliminary research efficiently without using laboratory animals. The second project evaluates the binding of collagen peptides to Fe to increase its solubility and bioavailability. The third project evaluates the ability of enzymatically and chemically produced glycopeptides to increase Fe bioavailability. Lastly, the fourth project is a tissue engineering approach developing the potential to create a consistent and sustainable future supply of GAGs. The supply of connective tissue raw materials may decrease in the foreseeable future due to ethical, environmental, and agricultural issues related to meat production and consumption. Bioactive GAGs can be produced from cultured fibroblasts isolated in our laboratory from different fish species. Ultimately, as we purify and control this “meat factor”, it represents the foundation to verify, improve, and build upon more sustainable resources and technologies, for designing special food formulations to increase Fe availability. This research will mostly benefit vulnerable Canadians, such as women, infants, and seniors, against Fe deficiency.