Pregnancy iron requirements

Iron deficiency affects more than 1.7 billion people worldwide and has been called the most widespread health problem in the world by the World Health Organization. Due to severe iron deficiency, more than 60 000 women die in pregnancy and childbirth each year, and almost 500 million women of childbearing age suffer from anemia. Dietary iron requirements depend on mrmerous factors, for example, age, sex, and diet composition. Recommended daily intake in the USA varies dependent on gender and age. Potato is a modest source of iron. A study of cultivated varieties showed 0.3-2.3 mg of Fe in a 100 g tuber (True et al., 1978). Ranges of iron content from 6 to 158 p,g/g of DW have been reported (Andre et al., 2007 Wills et al.. 

Pregnancy. The extra iron required by mother and fetus totals 1000 mg, chiefly in the latter half of pregnancy. The fetus takes iron from the mother even if she is iron deficient. Dietary iron is seldom adequate and iron and folic acid (50-100 mg elemental iron plus folic acid 200-500 micrograms/day) should be given to pregnant women from the fourth month. Opinions differ on whether all women should receive prophylaxis or only those who can be identified as needing it. There are numerous formulations. Parents should be particularly warned not to let children get at the tablets. 

In all cases of iron deficiency anaemia it is important to diagnose the underlying condition, especially malignant disea.se. the presence of intestinal parasites or any other intestinal pathology which may cause chronic blood loss. Iron deficiency may also develop during pregnancy, even in well-nourished women, due to the increased iron requirements of the developing fetus. 

IRON REQUIREMENTS AND THE AVAILABILITY OF DIETARY IRON Iron requirements are determined by obligatory physiological losses and the needs imposed by growth. Thus, adult men require only 13 /ig/kg/day ( 1 mg of iron), whereas menstruating women require 21 /ig/kg/day (-1.4 mg). In the last two trimesters of pregnancy, requirements increase to -80 /ig/kg/day (5-6 mg), and infants have similar requirements due to their rapid growth. These requirements (Table 53-3) must be considered in the context of the amount of dietary iron available for absorption. 

To attempt to meet iron requirements during pregnancy, iron absorption becomes more efficient in the second and third trimesters. Iron absorption nearly doubles in the second trimester and can increase up to four times in the third trimester. Despite this dramatic increase in iron absorption, it... 

Figure 2 The discrepancy between iron requirements and availability of iron from dietary absorption in pregnant women beyond 20weeks of gestation. The resulting iron deficit is maintained as pregnancy progresses into the second and third trimesters. (Reproduced with permission from the Food and Agriculture Organization of the United Nations (2001) Iron. In Human Vitamin and Mineral Requirements Report of a Joint FAOA/VHO Expert Consultation, Bangkok, Thailand, pp. 195-221. Rome FAO.)...

Pregnant women rarely have sufficient iron stores and consume diets adequate to maintain positive iron balance, particularly in the latter half of pregnancy, as previously discussed. They cannot meet their iron requirements through diet alone even in developed countries, where high iron content diets with high bioavailability are common. 

Pregnancy - Elemental iron 15 to 30 mg/day should be adequate to meet the daily requirement of the last 2 trimesters. 

Use and exposure Zinc is available as a silver or bluish-white foil or powder. It is incompatible with amines, cadmium, sulfur, chlorinated solvents, strong acids, and strong bases. The important use of zinc is to coat iron or steel in a process called galvanization to prevent rust. Zinc powder is very flammable. Zinc is another essential micronutrient that is important in immunity and antioxidation. Zinc is an essential mineral that is found in almost every cell function. It stimulates the activity of approximately 100 enzymes, which are substances that promote biochemical reactions in the body. Zinc supports a healthy immune system that the body requires for wound healing. It helps to maintain a sense of taste and smell and is needed for DNA synthesis. Zinc supports normal growth and development during pregnancy, childhood, and adolescence. ... 

Epoetin combined with parenteral iron is effective and safe for moderate and severe iron deficiency anemia during pregnancy (26), and iron supplementation is often required (27). The use of epoetin in combination with intravenous iron makes collection of larger numbers of autologous erythrocyte units feasible. However, epoetin does not synergize with G-CSF for the mobilization of peripheral blood progenitor cells in healthy donors (28). 

In monogastric species iron absorption takes place primarily in the upper small intestine (1). Not all the iron present in foods is absorbed into the body. In the normal adult with adequate stores of iron, usually less than 10% of the iron in foods is absorbed (2). Because of the body s limited capacity to excrete iron, the ability to refrain from absorbing unneeded iron is regulated in the duodenum and is referred to as the mucosal block (1). When the requirement for iron increases as in growth and pregnancy and in various disease and deficiency states, the mucosal block is modified and Increased iron absorption occurs. The explanation offered by Underwood (3) is as follows iron taken into the mucosal cell is converted to... 

The dietary requirement for iron depends on the amount and composition of the food, the amount of iron lost from the body, and variations in physiological state such as growth, onset of menses, and pregnancy. The average North American diet contains about 6 mg of iron per 1000 calories and supplies about 10-15 mg/d. Of that ingested, 8-10% (1-1.5 mg/d) is absorbed. Thus, dietary factors that affect absorption are more important than the iron content of the diet and may be more important for correction of iron deficiency than addition of iron to the diet. 

As has already been stated there is an increased requirement for the vitamin during pregnancy. This means that large numbers of women in the lower socioeconomic groups in many if not most countries will become folate deficient during pregnancy unless they are given additional folate to supplement that present in their diets. A similar problem exists with iron, and several pharmaceutical companies market a capsule which contains both iron and folic acid. 

Iron deficiency is the most common nutritional cause of anemia in humans. It can result from inadequate iron intake, malabsorption, blood loss, or an increased requirement, as with pregnancy. When severe, it results in a characteristic microcytic, hypochromic anemia. Iron is an essential component of myoglobin heme enzymes such as the cytochromes, catalase, and peroxidase and the metalloflavoprotein enzymes, including xanthine oxidase and the mitochondrial enzyme a-glycerophosphate oxidase. Iron deficiency can affect metabohsm in muscle independent of the effect of anemia on delivery, possibly due to a reduction in the activity of iron-dependent mitochondrial enzymes. Iron deficiency also has been associated with behavioral and learning problems in children, abnormahties in catecholamine metabolism, and impaired heat production. 

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