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

肌肉组织中的某些成分可以增强非血红素铁的吸收——这种现象被称为“肉因子”。缺铁性贫血是一种常见的营养失调，世界上20%至50%的人口没有足够的膳食铁。与年轻人相比，加拿大的老年人患贫血的比例更高，有趣的是，发达国家的缺铁通常不仅仅是饮食中的铁问题，而是吸收问题。我们感兴趣的是探索肉类因素，创造出可以帮助人们更好地吸收铁的食物。一种肉类因子分子是一种被称为糖胺聚糖（GAGs）的碳水化合物，存在于与肉类有关的所有组织中。gag是由附着在蛋白质上的无支链糖构成的。它们不仅存在于肉类中，也存在于软骨、肌腱和皮肤等结缔组织中，是肉类加工业中被低估和未充分利用的副产品。临床已经证明，作为口服补充剂，GAGs可以帮助治疗骨关节炎等关节问题（例如硫酸软骨素），但还需要更多的研究来证明GAGs如何用于其他应用，如改善铁的吸收。我们还在结缔组织胶原蛋白肽中添加了某些糖，以提高铁的生物利用度。

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.