Iron, Copper, and Zinc
19
T.S. Dharmarajan, Srinivas Guptha Gunturu,
and C.S. Pitchumoni
Questions and Answers
1. Which one of the following has highest bioavailable iron
content?
a. Chicken liver
b. Spirulina
c. Spinach
d. Almonds
Answer: a
Heme iron has better bioavailability than non-heme iron;
absorption of non-heme iron is subject to food component
interactions, such as phytates in greens. Although spirulina has highest non-heme iron content, its bioavailability
is less compared to chicken liver heme-iron. Spinach and
almonds are low in iron (below 5 mg per 100 g of food).
2. What is the role of hepcidin?
a. It promotes iron absorption
b. It inhibits iron absorption
c. Its role depends on the iron stores in the body
d. All of the above
Answer: b
Hepcidin is a 25-amino acid peptide produced by hepatocytes; production is dependent on iron status, inflammation,
hypoxia, and erythropoietin activity; this regulation of
iron absorption is termed the “gut–liver axis.” Hepcidin
inhibits iron absorption; its level is upregulated in the
presence of inflammation and iron overload and is downregulated in the presence of hypoxia, anemia, and erythropoietic activity.
3. An 80-year-old female comes to the clinic for weakness,
decreased exercise tolerance, irritability, decreased taste
sensation, and loss of appetite. She is obese and has had a
gastric bypass procedure. Routine lab: Hb: 8 g/dL, Hct: 24,
MCV 70 fL. Her ferrokinetics demonstrate transferrin saturation to be 7%, ferrtin level 12 ng/mL. EGD, colonoscopy,
small bowel series, hemoglobin electrophoresis, and sickle
screen are negative. What is the best modality of replacing
her iron?
a. Oral iwron
b. Iron sucrose
c. Iron dextran
d. All of the above
Answer: b
The patient has iron deficiency anemia. Using Ganzoni’s
formula: body weight [kg] × (target hemoglobin-actual
hemoglobin) [g/dL] × 2.4 + depot iron [mg], her total iron
deficit is [13.5–8 g/dL × 2.4 + 0.5 g] 13.7 g of iron. Oral
iron will be poorly absorbed with a history of gastric
bypass, and her anemia is severe. In this situation the best
option is parenteral iron. Iron dextran has a risk of anaphylactic reactions, life threatening in 1% of the patients
exposed, so this may not be an ideal choice today.
Intravenous iron sucrose can be given up to 1,000 mg in a
2-week period, and replenish iron stores in weeks.
4. A 70-year-old female with diabetes, hypertension, and
systemic lupus erythematosis has anemia. Lab values:
Hb: 10 g/dL, Hct: 33%, transferrin saturation is 14%, ferritin: 100 ng/mL. B12 and folate levels are in normal
limits. She has history of total abdominal hysterectomy
and bilateral salpingo-ophorectomy. She denies any history of menorrhagia or post-menopausal bleeding. Her
lupus flares up 2–3 times a year. She had EGD, colonoscopy, and small bowel series, without detecting any source
of bleeding. She was started on oral iron preparations 6
months earlier, but there was no improvement. What is
the cause of treatment failure?
a. Compliance issues
b. Chronic inflammation with increase in hepcidin activity,
interfering with iron reutilization
c. Both
d. None of the above
C.S. Pitchumoni and T.S. Dharmarajan (eds.), Geriatric Gastroenterology,
DOI 10.1007/978-1-4419-1623-5_19, © Springer Science+Business Media, LLC 2012
189
190
Answer: b
This patient has anemia of chronic disease, as a result of
ongoing inflammatory activity, which increases hepcidin
production in the liver. The higher hepcidin levels will
decrease gut iron absorption and decrease iron reutilization from macrophages leading to less functional iron
availability for erythropoiesis.
5. Copper absorption can be decreased by
a. Iron salts
b. Zinc salts
c. Both
d. None
Answer: c
Divalent metals such as copper, zinc, molybdenum,
cobalt, cadmium, nickel, and lead are competitively
absorbed at divalent metal ion transporter (DMT1) receptor in the enterocytes. When dietary zinc is excessive or
large amounts of zinc are administered over prolonged
periods, copper deficiency can result. While zinc induces
T.S. Dharmarajan et al.
intestinal metallothionein (MT), copper has greater
affinity for MT than zinc and displaces zinc, getting
trapped. Supplemental iron provided as ferrous form
(more so than ferric form) also has an inhibitory effect on
zinc absorption; the basis is competition for uptake at the
receptor level.
6. True statements about zinc deficiency include
a. Loop diuretics can cause zinc deficiency
b. Chronic oral iron therapy may cause zinc malabsorption
c. Zinc deficiency can result in loss of taste or altered taste
d. All of the above
Answer: d
Loop diuretics decrease zinc absorption at the loop of
Henle; chronic administration of oral iron supplements in
diabetes mellitus can cause zinc loss in the urine, mechanisms not clear. Iron supplementation for prolonged periods will decrease gut zinc absorption through competitive
action. Taste disturbances (aguesia and dysguesia) may
result from zinc deficiency.