Several weeks ago, I attended UC Davis’s Bioavailability conference in Pacific Grove, CA where researchers from around the world presented on numerous topics relating to micronutrient bioavailability that revealed exciting new research underway.
Iron was a centerpiece of many discussions because it is the most common micronutrient deficiency worldwide, technically challenging to fortify, and complex interactions control its bioavailability.
Various mechanisms in the body regulate iron homeostasis by sensing dietary iron content, iron storage levels, and erythropoietic iron requirements and then adjust iron absorption and transport accordingly (Sharp P., Srai SK. World J Gastroenterol 2007;13(35):4716-4724). In the lumen, specific iron transporters and/or dietary factors help reduce ferric iron to ferrous iron for absorption into the cell system, while others are responsible for duodenal iron transport and homeostasis. Day-to-day variability in iron absorption is governed by the presence of iron “enhancers” and/or “inhibitors” in the diet. Numerous enhancers exist including ascorbic acid, citric acid and other small organic acids, “meat factors” and certain amino acids. Phytates and polyphenols are two of the most strongly inhibitory factors present in cereal products and tea, but other iron inhibitors may include calcium, phosphates, oxalates and egg protein. Diet factors may also influence gene expression of iron transporters. For example, the dietary polyphenol (-) -epigallocatechin-3-gallate (EGCG) is a strong inhibitor of iron transport in Caco-2 cells (Kim, Eun-Young, Ham, Soo-Kyung, Shigenaga, Mark K., Han, Okhee. J. Nutr. 2008 138: 1647-1651). Iron homeostasis is also controlled by various systemic regulators and of these hepcidin is the key regulator of iron metabolism.
The research underway to better understand these mechanisms and how they interact with dietary factors, inflammatory states (including obesity) and genetic polymorphisms may lead to future advances in nutrient bioavailability. These issues are important to PepsiCo because we have committed to providing consumers with innovative, highly nutritious food products. We look forward to future dialogue and potential collaboration with researchers involved in nutrient bioavailability research as a means of helping improving nutrition in developing and developed countries.