Question

Assignment: Using the text and LibGuides Describe the interaction between 1) copper and iron 2) copper and zinc and 3) zinc and iron - specifically with absorption and transportation in the body. Use at least 50 words for each of the 3

Answer 1

Ans) 1) There is a recognized and poorly understood relationship between iron and copper metabolism in our bodies. Some cases of iron deficiency anemia cannot be relieved by the consumption of iron but can be successfully treated by the consumption of copper.

The best current explanation of the relationship of iron to copper is based on the protein caeruloplasmin (ceruloplasmin),which binds copper and acts as an iron carrier in our bodies. When copper absorption is low due to low consumption the caeruloplasmin levels drop. This means that less caeruloplasmin is available to transport iron around the body where it is needed to make red blood cells. The iron remains where it is stored and the result appears to be a deficiency of iron resulting from a deficiency of copper. Iron deficiency appears the same as does copper deficiency anemia on laboratory tests of red blood cells.

It has been know since 1928 that copper could improve the blood’s hemoglobin formation. Now, we know that a person who has borderline iron deficiency can become overtly anemic when his or her blood levels of copper drop.

It is not known how low copper levels reduce caerulopasmin. Ninety-five percent of the copper is bound to caeruloplasmin. Caeruloplasmin does not transport copper about the body as it does for iron. Copper balance is partly controlled by the release of copper in the bile and increased amounts of bile production will result in loss of more copper from the body. The average daily intake of copper is .6 to 1.6 mg per day.

2) The zinc metal is coated with dark-black elemental copper. The copper metal, however, has no reaction with the ZnSO4 solution.

The iron metal is coated with red-bronze metallic copper.

Explanations (including important chemical equations):

Zn (s) + CuSO4 (aq) ----> Cu (s) + ZnSO4 (aq)

stronger reducing agent stronger oxidizing agent weaker reducing agent weaker oxidizing agent

Cu (s) + ZnSO4 (aq) ---> Zn (s) + CuSO4 (aq)

Fe (s) + CuSO4 (aq) ---> Cu (s) + FeSO4 (aq)

Oxidation occurs when the oxidation number of an atom becomes larger. Reduction occurs when the oxidation number of an atom becomes smaller. Oxidizing agents gain electrons while reducing agents lose electrons. Generally, when metals are fully reduced, they form elemental metal and "plate" the site where they were reduced.

In the first reaction, the copper ion is able to oxidize the zinc metal. However, in the second reaction, the zinc ion is not able to oxidize the copper metal. Zinc is a better reducing agent than copper. Strong reducing agents have weak conjugate oxidizing agents. Zn2+ is a weak conjugate oxidizing agent compared to Cu2+. Conversely, strong oxidizing agents have weak conjugate reducing agents. The second reaction did not occur because the reactants were the weaker reducing and oxidizing agents. In the third reaction, iron is a better reducing agent than copper, however iron is not as good as zinc.

3) Iron deficiency is the most common nutritional deficiency in the world; zinc deficiency is associated with poor growth and development and impaired immune response. Several Third World countries are taking measures to increase the dietary intake of iron and zinc with fortification of foods or dietary supplements. 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. The total amount of ionic species affects the absorption of zinc and that a total dose of >25 mg Fe may produce a measurable effect on zinc absorption. This could occur if iron supplements are taken with a meal, and iron experts recommend that iron supplements be taken between meals. Recent studies using stable isotopes showed that fortifying foods with iron at current fortification amounts has no adverse effect on zinc absorption. There are 5 zinc salts listed as generally recommended as safe (GRAS) by the US Food and Drug Administration for food fortification. From 1970 to 1987, the total amount of zinc salts used in food continually increased, with zinc oxide and zinc sulfate showing the largest increases. Twelve iron sources are listed as GRAS; elemental iron has become the source of choice because it is less expensive to produce and has fewer organoleptic problems. Use of ferrous fumarate is also increasing.