AP BIOLOGY

Detailed explanation-1: -Fe, Cu, and Zn are cofactors in processes of protein synthesis. This explains why their role is essential in the functioning of many organs and systems (Figure 1) [2]. Some proteins act as enzymes while others play a structural role; for example, the hemoglobin and DNA.

Detailed explanation-2: -Several studies showed that high iron concentrations can negatively affect zinc absorption in adults when these trace minerals are given in solution. However, when iron and zinc are given in a meal, this effect is not observed.

Detailed explanation-3: -Zinc and iron interact competitively during intestinal absorption. When both nutrients are ingested simultaneously in aqueous solutions at levels commonly used in supplements, there is evidence that an excess of iron inhibits zinc absorption (1, 2) and that excess zinc inhibits iron uptake (3).

Detailed explanation-4: -We have demonstrated that zinc induces iron uptake and transcellular transport in intestinal cells via induction of DMT1 and FPN1 expression [16, 17, 19, 20]. Therefore, zinc appears to be a key modulator of intestinal iron absorption and tissue iron distribution possibly mediated via regulating the DMT1 and FPN1 levels.

Detailed explanation-5: -Iron and zinc deficiencies are the most common nutritional deficiencies worldwide. Combined zinc and iron supplementation are one of the strategies used to prevent these deficiencies. Zinc has an inhibitory effect on iron absorption.