Some truths about iron

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Friday, February 28, 2014

THE importance of iron in the normal physiologic functions of our body cannot be overemphasized.

Iron is involved mainly in the transfer of oxygen, which is needed by the body at numerous cellular levels.

It is a vital element needed by the body especially during pregnancy, lactation, growth, extraneous physical activities and in times of morbidities that involve iron loss such as bleeding.


In cases when insufficient iron exists, iron-deficiency anemia may result.

According to the guidelines set by the World Health Organization (WHO), the amount of daily absorbed iron needed by the body are as follows: adult males- 1.14 mg; menstruating women- 2.38 mg; lactating women- 1.31 mg; and post-menopausal women- 0.96 mg.

For pregnant women, however, WHO recommends a total of 1,000 mg of absorbed iron throughout the course of pregnancy.

Notice that these literatures emphasize the word 'absorbed'; meaning, it is not to be equated with the actual or raw amount of iron derived from the diet or food supplements as in the case of vitamin capsules.

The reason for this is that not all the iron we consume—through food or supplements—are readily absorbed.

Basically, iron is derived from the diet.

As a matter of fact, one source states that the amount of iron present in a Filipino diet is 11 grams but only 5 to 10 percent is absorbed in the stomach.

The remaining 90 to 95 percent of the total iron consumed either goes to the circulation (blood as plasma), where it functions as a reservoir in times of needs or are stored to the bone marrow to form hemoglobin, a component of the red blood cell that functions as vessels of oxygen for it to be transported to the rest of the body.

However, another source shares that there are two forms of iron: heme and non-heme iron.

The 'heme' type of iron is contained in food sources like meat, fish and blood products.

On the other hand, the 'non-heme' is common to plant sources of food like vegetables, fruits, grains and nuts.

Studies have long proven that the heme type of iron is well absorbed in the body compared to the non-heme iron.

Conversely, one can enhance the absorption of the non-heme iron by consuming ascorbic acid, amino acids or ingestion of meat, fish and poultry.

On the contrary, non-heme iron absorption is inhibited by calcium, soybeans and tea.

Unfortunately, the iron contained in an egg-yolk has a substance called 'phosvitin' which also inhibits iron absorption.

Generally speaking, iron is excreted regularly in the feces, urine and sweat.

It therefore follows that athletic people (especially those who engage in body building and contact sports), people with diarrheal and urinary problems lose more iron than an average healthy person and therefore may need to increase oral intake of iron.

A menstruating woman, for example, loses about 37 to 70 mL of blood that would have contained 16 to 32 mg of iron.

For infants, the best source of iron is the breast milk compared to iron-fortified formula milks despite the fact that the latter contains more iron than the former.

However, the iron contained in the breast milk is more readily absorbed compared to formula.

Other conditions that cause iron loss include blood loss, parasitism (like malaria and hookworm infections) and haemolytic anemia (blood destruction due to an autoimmune process, bacterial toxin or food poisoning).

In another vein, too much consumption of iron may lead to iron toxicity or poisoning with the following symptoms: bleeding, metabolic acidosis, liver damage and kidney failure.

In worst scenarios, death can occur in 12 to 48 hours.

Meanwhile, WHO shares the following figures in determining the amount of elemental iron contained in commonly prepared iron supplements: per 200 mg ferrous fumarate contains 66 mg elemental iron; per 200mg ferrous sulfate has 74 mg; and per 300mg ferrous gluconate has 36 mg.

Most pharmaceutical companies manufacturing iron supplements in the form of ferrous sulfate warn that intake beyond 150mg of elemental iron causes gastrointestinal discomforts like abdominal cramping, diarrhea and gastrointestinal bleeding.

According to Maurice Vincent Revilla, a practicing chemist, an elemental iron refers to the pure form of the metal iron (or in the absence of sulfate in the case of ferrous sulfate).

In fact, one commercial ferrous sulfate supplement that is available in the market contains 325 mg of ferrous sulfate per tablet but its elemental iron content is only 65 mg.

Lastly, the following are some of the things to observe when taking iron supplements: stool may appear dark; do not bite the table form as it may stain the teeth; and too much iron can causes stomach upsets.

Sources: Basic Diet Therapy for Filipinos; Comprehensive School health Education; Focus on Nursing Pharmacology; Preventing & Controlling Iron Deficiency Anemia; World Health Organization


Published in the Sun.Star Cagayan de Oro newspaper on February 28, 2014.


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