Question

Heme is the iron-containing structure in the proteins hemoglobin and myoglobin. In red blood cells, hemoglobin enables oxygen uptake and transport. Myoglobin in muscle cells helps oxygen enter the cells. The oxygen carried by hemoglobin and myoglobin is critical for energy production.

Because meat contains hemoglobin and myoglobin, beef, fish, and poultry contain more heme iron than most plant foods. The remaining iron in meat, as well as all the iron in vegetables, grains, dietary supplements, and fortified or enriched foods, is nonheme iron. More heme iron than nonheme iron is absorbed in the intestinal tract. Absorption of heme iron ranges from 15 to 35%, whereas absorption of nonheme iron ranges from 2 to 20%.

Products made from enriched cereal grains are other important dietary sources of iron. However, the small intestine absorbs only about 5% of the iron salts that have been added to grain products, because iron salts are not as bioavailable as heme iron. Dairy products are poor sources of iron.

Under normal conditions, the body closely regulates iron absorption and conservation. The digestive system of healthy people absorbs only 5 to 8% of the iron that is in a typical diet. However, the intestinal tract can absorb more iron when the body’s need for the trace mineral increases. For example, absorption of nonheme iron can be as high as 23% in women who are iron-deficient.

1.Hyponatremia is associated with dehydration because a loss of body water results in a high blood salt concentration.True or False

2. ________ helps oxygen enter muscle cells.

A.Transferrin

B. Hemoglobin

C. Myoglobin

D. Ferritin

3. Which of the following is the best source of heme iron?

A. Milk

B. Black beans

C. Enriched cereal

D. Fish

4. Heme iron ________.

A. is more readily absorbed than nonheme iron

B. is found predominately in plant food sources

C. competes with vitamin C for absorption

D. All of the choices are correct.

5. The amount of nonheme absorbed ________ during pregnancy (a time of greater need for iron).

A. does not change

B. increases

C. decreases

Answer 1

Note: Only the first four parts/questions can be answered at once. Therefore question (1-4) have been answered properly with explanations.

Question 1:

Answer: False.

Explanation: Hyponatremia is a condition in which blood sodium level is too low due to excess water intake which dilutes the sodium in the body which causes swelling of cells. It is not associated with dehydration but rather associated with overhydration.

Question 2:

Answer: Option B. Hemoglobin.

Explanation: Hemoglobin is the red-pigmented particle which binds with the oxygen molecules and carries it within the bloodstream.

Question 3:

Answer: Option D. Fish.

Explanation: Heme iron is associated with iron sources associated with animal meat. Therefore, it can be found in excess in meat products only. And among the options given only fish is a meat/flesh product. Therefore, fish is the best source for heme iron.

Question 4:

Answer: Option A. is more readily absorbed than nonheme iron.

Explanation: Heme iron is more easily absorbed and therefore it serves as a large source of dietary iron for people whereas Non-heme iron is generally less readily absorbed than heme iron. The other options are incorrect and false.