Iron Absorption From The Whole Diet: Comparison Of The Effect Of Two D :: essays research papers fc

Iron Absorption from the Whole Diet Comparison of the Effect of Two DifferentDistributions of Daily Calcium IntakeHypothesis - If a woman distributes her daily use of goods and services of calcium by having lessof it in her lunch and dinner meals and more in her breakfast and evening meals,then this would centre the repressive effects calcium has on heme crusade andnonheme iron absorption.Background Information - This experiment is one of many that addresses calciumsinhibitory affects on iron absorption. In 1994, the Consensus Development Panelin Optimal Calcium Intake suggested an increase of the current RecommendedDietary Allowances of calcium(Whiting, p.77). This goal of this increase was to attending in the prevention of osteoporosis and other bone diseases. Unfortunately,this attempt at prevention could have an adverse affect on the human bodys world power to absorb iron.Recent studies have shown that eating a normal daily allowance ofcalcium cuts iron absorption by as much as 50-60%(Hallberg et al. p.118). Otherstudies examine the affect of iron bioavailability on menstruating, pre-menopausal, and post-menopausal women(Rossander-Hulten et al and Gleerup et al).One of the fears of an increased amount of calcium intake is the increasedpossibility of anemia in women who are already susceptible to this condition.The iron inhibition by calcium is a classical example of how the correction ofone nutritional problem croup be the cause of another.The physiological mechanism of this calcium-iron relationship remains amystery, however there are two feasible theories. One states that calciumcompetes for an iron binding site on intestinal epithelial cells. It isbelieved calcium binds to the protein mobilferrin on the epithelial cells, whichis the iron transport protein(Whiting, p.78). some other group of scientiststheorizes that iron is able to be transported into the epithelial cells withoutproblem, however the iron then has trouble getting into the blood strea m. Thepresence of calcium inhibits irons ability to leave the epithelial layer.Another very interesting theory is not on the microscopic level but inthe evolutionary plane. Eaton et al. state that one possibility for thisphenomenon could lie in the Homo sapiens genetic ancestry. As little as 200years ago humans had almost double the amount of calcium intake as they do inthe show, because humans evolved in a high-calcium nutritional environment.With the decrease in calcium, there has also been a large decrease in physicalactivity(Eaton et al.). The inhibitory effect of calcium on iron absorptioncould be related to the low intakes of iron and calcium in conjunction with thepresent low-energy lifestyle(Glerrup et al. p. 103).Terms -Extrinsic radioisotopic iron tracer - Radioisotopes of iron (59Fe and 55Fe)