Iron

Question 1

• Iron-sulfur complex (aconitase) in the Krebs cycle links the iron content with energy production via oxidative phosphorylation.

Answer 1

• Iron-sulfur complex (aconitase) in the Krebs cycle links the iron content with energy production via oxidative phosphorylation.

Question 2

Heme Iron 25% abs.

Answer 2

Heme Iron 25% abs.

Question 3

Non-Heme Fe- found in plant derived foods – only 17% of this Fe is absorbed.

Answer 3

Non-Heme Fe- found in plant derived foods – only 17% of this Fe is absorbed.
• Fe deficient people absorb hig

Question 4

Mean rate of absorption from all sources is 18% from vegetarian diets (no MFP). It can vary from 2% in GI disease, to 35% in a healthy growing child.

Answer 4

Mean rate of absorption from all sources is 18% from vegetarian diets (no MFP). It can vary from 2% in GI disease, to 35% in a healthy growing child.

Question 5

Surplus Fe is stored in the protein ferritin in the liver, spleen, & bone marrow.

Answer 5

Surplus Fe is stored in the protein ferritin in the liver, spleen, & bone marrow.

Question 6

When dietary intake excessive, ferritin hemosiderin (Fe storage protein).
• Hemosiderin releases Fe more slowly than ferritin—protective mechanism:
free Fe acts as a free radical, attacking cell lipids, DNA, proteins.

Answer 6

When dietary intake excessive, ferritin hemosiderin (Fe storage protein).
• Hemosiderin releases Fe more slowly than ferritin—protective mechanism:
free Fe acts as a free radical, attacking cell lipids, DNA, proteins.

I

Question 7

Surplus Fe is stored in the protein ferritin in the liver, spleen, & bone marrow.

Answer 7

Surplus Fe is stored in the protein ferritin in the liver, spleen, & bone marrow.

Question 8

RBC lives about 4 months
Liver & spleen remove RBC from circulation, dismantle
Salvaged Fe is attached in the liver to blood transferrin
transport Fe back to bone marrow

Answer 8

RBC lives about 4 months
Liver & spleen remove RBC from circulation, dismantle
Salvaged Fe is attached in the liver to blood transferrin
transport Fe back to bone marrow

Question 9

Serum Ferritin – reflects iron stores, low in 1st stage of Fe deficiency
- - the most valuable determinant of iron status

Serum Iron – marks 2nd stage of Fe deficiency

Serum Transferrin – Fe carrier protein; In the 2nd stage of Fe deficiency, it increases to enhance Fe absorption.

Question 10

Prior to the occurrence of Fe-deficiency anemia, even a Mild Fe deficiency
Impaired pyruvate oxidation

Answer 10

Prior to the occurrence of Fe-deficiency anemia, even a Mild Fe deficiency
Impaired pyruvate oxidation

Question 11

• Iron overload – also known as hemochromatosis, is a genetic disorder that enhances Fe absorption (1.5 million people in the US, the most common genetic problem in the US), potentially due to deficiency of hepcidin, which supports iron homeostasis. Can also be caused by repeated blood transfusions, large doses of supplemental Fe.

Question 12

Hemochromatosis : genetic disorder that enhances Fe abs. Deficiency of hepcidin which supports iron homeostasis

Question 13

Hemosiderosis – a condition characterized by large deposits of Fe storage protein hemosiderin in the liver & other tissues; caused by long-term over-consumption of Fe. More common in men than women.

Question 14

Heart Disease
• In certain diseases free radicals attack ferritin
release Fe from storage.
• Free iron = oxidant, generating more radicals:
-Fe oxidizes LDL, which may lead to heart disease.
-Repeat blood donors have lower risk of CHD, perhaps due to low Fe.
• The protection of pre-menopausal women from heart disease may also be due in part to lower Fe stores.
Cancer
• Free Fe radicals can damage DNA.
• Fiber may be protective, partially due to its phytates binding Fe.

Answer 14

Heart Disease
• In certain diseases free radicals attack ferritin
release Fe from storage.
• Free iron = oxidant, generating more radicals:
-Fe oxidizes LDL, which may lead to heart disease.
-Repeat blood donors have lower risk of CHD, perhaps due to low Fe.
• The protection of pre-menopausal women from heart disease may also be due in part to lower Fe stores.
Cancer
• Free Fe radicals can damage DNA.
• Fiber may be protective, partially due to its phytates binding Fe.

Question 15

Hormone hepcidin produced by liver maintains blood iron by inhibiting absorption and transport to storage as needed.

Answer 15

Hormone hepcidin

Question 16

Hemochromatosis-Inhances Fe absorption-deficiency in hepcidin

Question 17

• Hemosiderosis – a condition characterized by large deposits of Fe storage protein hemosiderin in the liver & other tissues; caused by long-term over-consumption of Fe. More common in men than women.