The Effects of Oral Iron Supplementation

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_volume


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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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Documents

The Effects of Oral Iron Supplementation