2. Iron in Food and Nutrition
People in former days often adopted sound nutritional habits without really knowing why those habits were good ones. For example, we are told that parents in Eastern European nations formerly inserted-iron nails into apples which they later gave their children to eat. Without knowing the correct nutritional explanation, these people had discovered that iron somehow improved the health of their children. Today, we have a better chemical understanding of what happens in this process. Acids in the apple react with and dissolve a small amount of iron from the nail. That iron is then ingested when the apple is eaten, satisfying the small, but essential, requirement for iron that humans have. In earlier days, humans also obtained iron when food was cooked in iron pots and when water was stored and transmitted through iron
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In recent years, some chemists have been interested in learning more about the effects on nutrition of not having nails stuck into apples, not cooking foods in iron pots, and not drinking water from iron pipes. In some w’s, the obvious result has been to reduce the amount of iron we obtain naturally every day from -normal cocking, eating, and drinking habits. But studies have shown that there may be benefits from these changes also.
Those benefits arise from the fact that the dissolving of iron from nails, iron pots, and iron pipes is a complex chemical process involving other nutrients. For example, vitamin C (ascorbic acid) promotes the dissolving of iron by converting iron alp ions to iron (H) ions. During the dissolving process, the ascorbic acid is oxidized to a less stable form, dehydroascorbic acid. This form of the vitamin is still nutritionally useful, but it is much more easily destroyed by heat and oxidation
0 CHOHCH2OH
H
HO’ ‘OH
ascorbic acid Fe 3+
Fe 2+ dehydroascorbic aC d
The advent of stainless steel pots and copper pipes has been, therefore, a mixed blessing from a nutritional standpoint. We probably get less iron, an important nutrient, from the environment than we once did. But the vitamin C in our foods is probably in a more stable form than it once was.
Questions and Problems I . Answer a) or b): apescribe how iron and hemoglobin interact. How are they used by our bodies? b)Describe a biological function of hemoglobin. Write the chemical reaction fir the function.
2. Find out what difference it makes from a nutritional standpoint (if any) whether iron exists in the body . as ferric or as ferrous ion.
3. What is the minimum daily requirement of iron?
4. What are negative effects of having too much iron in de body? What disease may it cause?
