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7/29/2019 The Effects of Oral Iron Supplementation
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The effects of oral ironsupplementation oncognition in older children and
adults:
a systematic review and meta-analysis
Martin Falkingham1, Asmaa Abdelhamid1,Peter Curtis1, Susan Fairweather-Tait1,Louise Dye2, Lee Hooper1
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Iron
Iron plays an important role in biology,forming complexes with molecular oxygenin hemoglobin and myoglobin: these twocompounds are common oxygentransport proteins
Iron is a chemical element with thesymbol Fe (from Latin: ferrum), which includeferrous and ferric compounds, have manyuses.
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HEME Iron Food SourceServing
Size (oz.)
Iron
(mg)
*Beef, chuck, lean 3.0 3.2
Beef, corned 3.5 1.9Beef, eye of round, roasted 3.0 2.2
*Beef, flank 3.5 3.3
Beef, lean ground; 10% fat 3.0 3.9
Beef, liver 3.0 7.5
*Beef, round 3.5 3.1
Beef, tenderloin, roasted 3.0 3.0
Chicken, breast, roasted, 3.0 1.1
Chicken, leg, meat only, roasted 3.5 1.3
Chicken, liver 3.5 12.8
Clams, breaded, fried, cup 3.0
Oysters, breaded and fried 6 pieces 4.5
Turkey, dark meat 3.5 2.3
Turkey, white meat 3.5 1.6
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NON-HEME Iron
Food SourceServing Size Iron (mg)
Baked beans, canned cup 2.0
Black beans, boiled 1 cup 3.6Kidney beans, boiled 1 cup 5.2
Lentils, boiled 1 cup 6.6
Lima beans, boiled 1 cup 4.5
Molasses, blackstrap 1 tbsp. 3.5Navy beans, boiled 1 cup 4.5
Oatmeal, fortified instant, prepared 1 cup 10.0
Pinto beans, boiled 1 cup 3.6
Soybeans, boiled 1 cup 8.8
Spinach, cooked (boiled, drained) cup 3.2
Spinach, canned, drained cup 2.5
Spinach, frozen, boiled, drained cup 1.9
Tofu, raw, firm cup 3.4
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The following factors will increase the
iron absorption from non-heme foods
A HEME and NON-HEME food eaten
together A good source of vitamin C (ascorbic acid) -
i.e., oranges, grapefruits, tomatoes, broccoli
and strawberries, eaten with a NON-HEME
food A NON-HEME food cooked in an iron pot,
such as a cast iron skillet
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The following factors will decrease the
iron absorption from non-heme foods
Excess consumption of high fiber foods or
bran supplements (the phytates in suchfoods inhibit absorption).
Large amounts of tea or coffee consumed
with a meal (the polyphenols bind the iron).
High intake of calcium - take your calciumsupplement at a different time from your iron
supplement.
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Iron
Metabolism
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Iron Deficiency
Causes
Chronic bleeding (hemoglobin contains iron)
excessive menstrual bleeding
non-menstrual bleeding bleeding from the gastrointestinal tract (ulcers, hemorrhoids,
etc.)
rarely, laryngological bleeding or from the respiratory tract
Inadequate intake (special diets low in dietary iron)
Substances (in diet or drugs) interfering with iron absorption Malabsorption syndromes
Fever where it is adaptive to control bacterial infection
Blood donation
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Iron Deficiency
Symptom
Fatigue
Pallor
Hair loss Irritability
Weakness
Pica
Brittle or grooved nails
Plummer-Vinson syndrome: painful atrophy of the mucousmembrane covering the tongue, the pharynx andthe oesophagus
Impaired immune function
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Iron Supplements
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Iron Supplements
Iron supplementation is indicated when diet
alone cannot restore deficient iron levels tonormal within an acceptable timeframe.
Supplemental iron is available in two forms:
ferrous and ferric. Ferrous iron salts (ferrous
fumarate, ferrous sulfate, and ferrousgluconate) are the best absorbed forms of
iron supplements
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Iron Supplements
Therapeutic doses of iron supplements, may
cause gastrointestinal side effects such asnausea, vomiting, constipation, diarrhea,
dark colored stools, and/or abdominal
distress
Starting with half the recommended doseand gradually increasing to the full dose will
help minimize these side effects
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Anemia
Anaemia, defined as a reduction in the
quantity of the oxygen-carrying pigmenthaemoglobin in the blood, is a major global
public health problem.
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Anemia
Microcytic
Microcytic anemia is primarily a result of hemoglobin synthesisfailure/insufficiency, which could be caused by severaletiologies:
Heme synthesis defect
Iron deficiency anemia
Anemia of chronic disease (more commonly presenting asnormocytic anemia)
Globin synthesis defect alpha-, and beta-thalassemia
HbE syndrome
HbC syndrome
and various other unstable hemoglobin diseases
Sideroblastic defect
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Anemia
Macrocytic
Megaloblastic anemia, the most common cause of macrocyticanemia, is due to a deficiency of either vitamin B12, folicacid (or both). Deficiency in folate and/or vitamin B12 can bedue either to inadequate intake or insufficient absorption. Folatedeficiency normally does not produce neurological symptoms,while B12 deficiency does.
Hypothyroidism
Alcoholism commonly causes a macrocytosis, although not
specifically anemia. Other types of liver disease can also causemacrocytosis.
Methotrexate, zidovudine, and other drugs that inhibit DNAreplication.
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Anemia
Normocytic
Normocytic anemia occurs when the overall
hemoglobin levels are always increased, but the redblood cell size (mean corpuscular volume) remainsnormal. Causes include:
Acute blood loss
Anemia of chronic disease Aplastic anemia (bone marrow failure)
Hemolytic anemia
http://en.wikipedia.org/wiki/Mean_corpuscular_volumehttp://en.wikipedia.org/wiki/Mean_corpuscular_volume7/29/2019 The Effects of Oral Iron Supplementation
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Cognition
Cognition refers to mental processes. These
processes include attention, remembering,producing and understanding language,
solving problems, and making decisions.
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Background
In observational studies anaemia and iron
deficiency are associated with cognitivedeficits, suggesting that iron supplementation
may improve cognitive function. However,
due to the potential for confounding by socio-
economic status in observational studies, thisneeds to be verified in data from randomised
controlled trials (RCTs).
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Aim
To assess whether iron supplementation
improved cognitive domains: concentration,intelligence, memory, psychomotor skills and
scholastic achievement.
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Result
Attention/Concentration
The effect of iron supplementation on attention or
concentration was assessed in 3 groups of anaemicparticipants (146 people) and two groups of irondeficient and/or replete participants (33 people)
One study in Indonesian primary school children found
an improvement in attention and concentration relatedto iron supplementation, while the remaining fourstudies (in US adolescents and pre-menopausalwomen, New Zealand teenagers and Mexican primaryschool children) found no statistically significant effects
on measures of attention or concentration
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Result
Intelligence
The effect of iron on intelligence quotient (IQ)was assessed in three groups of anaemic
participants, two of iron deficient people and
six groups of those who were iron replete at
baseline Overall there was no evidence of an effect of
iron supplementation on intelligence
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Result
Memory
Four studies addressed the effect of ironsupplementation on memory in anaemic
participants, none in iron deficient people
There was no evidence overall
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Result
Psychomotor function
The domain of psychomotor function wasinvestigated by 4 studies in those anaemic at
baseline, 2 in iron deficient and/or replete
participants and 1 in iron replete participants
There was no suggestion of an effect of ironsupplementation on psychomotor function
overal
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Result
Scholastic achievement
The effects of iron supplementation on scholastic
achievement appeared highly heterogeneous - two
studies showed statistically significant improvement,
and two showed statistically significant impairment to
scholastic achievement from iron supplementation
compared with the control group at end of study. Overall, there was no suggestion of a significant
effect
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Conclusions
There was some evidence that ironsupplementation improved attention,
concentration and IQ, but this requiresconfirmation with well-powered, blinded,independently funded RCTs of at least oneyears duration in different age groups
including children, adolescents, adults andolder people, and across all levels ofbaseline iron status.
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