Prevention of Micronutrient Deficiencies Tools for Policymakers and Public Health Workers (1998) / Chapter Skim
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3 PREVENTION OF IRON DEFICIENCY
3 PREVENTION OF IRON DEFICIENCY
Pages 45-102
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From page 45... ...
Iron deficiency also impairs the transformation of the thyroid hormones, T4 to T3, in peripheral tissues, the production and metabolism of epinephrine and norepinephrine, and leads to difficulty in maintaining body temperatures upon exposure to cold (Beard, 1990~. Functional consequences of severe iron-deficiency anemia during pregnancy include increased rates of premature delivery, perinatal complications in mother and newborn, low birthweight, low iron stores, and indications of iron deficiency and anemia in the newborn or in later infancy.
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From page 46... ...
Because of the high iron requirements of pregnancy, iron deficiency is the rule, particularly in teenage gestations and in women with frequent pregnancies. The stages in the development of iron deficiency are the depletion of iron stores, as indicated by low plasma ferritin; interference with biochemical processes, indicated by low transferrin saturation and elevated free erythrocyte protoporphyrin and serum transferrin receptors; and, finally, anemia, as indicated by low hemoglobin.
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From page 47... ...
Prepregnancy iron nutrition and hemoglobin level markedly influence the development of gestational anemia (Kauffer and Casanueva, 1990~. There is thus a need to consider interventions that will improve prepregnancy iron reserves and provide extra amounts of iron, in addition to that in the diet, during gestation (Sloan et al., 1992; Viteri, 1994a,b, in press a,b)
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From page 48... ...
It is favored by the ingestion of sufficient iron in food (native, or added through fortification) in a bioavailable form or through iron supplementation.
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From page 49... ...
>20 1 2.0-1 9.9 5.0-1 1.9 2. Records of anemia in health centers and clinics, as well as among hospital inpatient and outpatient pregnant women, women of childbearing age, and children between 6 and 36 months of age.
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From page 50... ...
In normal individuals, heme iron absorption fluctuates between 15 and 30 percent, but can increase up to about 50 percent in iron-deficient anemic subjects and can decrease to about 5-8 percent when the amount of heme iron is around SO mg (Cook, 1990; Layrisse et al., 1973; Viteri et al., 1978~. The nonheme iron pool is made up of all other sources of irons.
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From page 51... ...
Cook (1990) has also summarized the importance of iron nutritional status on heme and nonheme iron absorption in a single meal containing= both kinds of iron (see Table 3-2~.
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From page 52... ...
In humans, the absorption data are not as clear, but they suggest that for less than 1 week of daily iron supplementation, or even with 2 to 4 daily doses, the blockage is minor, if it operates at all, among nonanemic and normal or mildly iron-deficient subjects (Cook and Reddy, 1995; Hoglund, 1969; Norrby, ]
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From page 53... ...
Vitamin A is involved in mobilization of iron reserves, in Hb synthesis, and appears to favor iron absorption in the presence of inhibitors (Hodges, et al., 1978; Layrisse et al., 1997; Mejia et al., 19794. Low dietary iron intakes- particularly where much of the iron is in nonheme form combined with the increased iron needs of growth or pregnancy, and even the small chronic iron losses of mildly excessive menstrual flow, increase the risk of developing iron deficiency and anemia.
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From page 54... ...
Heart failure from myocardial dysfunction and diabetes brought about by pancreatic disease are suggested rare consequences, but this remains highly controversial (Lynch, 1995~. The adoption of general iron fortification of foods in the developing world, where iron deficiency is highly prevalent, has been slowed further by fears of accelerating iron overload conditions in genetically prone individuals, even though this is a relatively rare clinical problem.
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From page 55... ...
, but IUDs can be effectively used in combination with some form of iron supplementation. Birth spacing and delaying pregnancy beyond the teen years allow the deposition or recovery of iron reserves after the pubertal growth spurt or a previous pregnancy (Beard, 1994; Bothwell et al., 1979; INACG, 19813.
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From page 56... ...
56 Cal as ._ sit ~2 o A: o Ad C: so: Ce ·Cal Cat ._ ~ I: ¢ _ 1 Ce - t:: o =: U: ~ ~:5 ._ o o C)
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From page 57... ...
57 A: Cal ~ ._ .
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From page 58... ...
This investigation compared the effect of daily and weekly iron supplementation on iron nutrition by studyin~, all of the children, whether or not they were iron deficient or anemic. In that population, 39 percent of the children were iron deficient (serum ferritin <20
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From page 59... ...
. Children were randomly assigned to 3 months of directly supervised iron supplementation.
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From page 60... ...
. This program was extensively evaluated and proved that it could effectively prevent iron deficiency and increase iron reserves in menstruating adolescent girls attending school, reducing the proportions of girls with serum ferritin < 20 ~g/1 from 33 to 17 percent.
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From page 61... ...
Only recently has attention been given to menstruating, women as targets for iron supplementation. In the United States, an ad hoc expert panel on iron deficiency in women of childbearing age recommended that nonpregnant women be treated with 60 to 180 mg of iron/day if they are found anemic and their serum ferritin levels < 20 Gal (Anderson, 1991~.
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From page 62... ...
~, - ~ Pregnant Women The regulation of iron metabolism in pregnancy is unique, because profound hormonal changes, functional adaptations, and large increments in iron requirements occur during this time. Iron absorption increases as pregnancy advances (Barrett et al., 1994; Hahn et al., 1951; Heinrich, 1970; Svanberg' 1975; Whittaker et al., 1991~.
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From page 63... ...
Hb concentration usually reaches its lowest concentration by 20-28 weeks gestation, and many ofthe women who develop anemia remain anemic after delivery (Hytten and Duncan, 19569. Iron supplementation of pregnant women has been viewed as the main global strategy for controlling iron deficiency and anemia.
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From page 64... ...
, which was directed to the developing world, recommended universal iron supplementation for pregnant women (60 mg of elemental iron and 250 as, of folio acid, once or twice daily) through the primary health care system.
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From page 65... ...
Nevertheless, no women in either of the groups ended with a Hb value below 95 g/1, indicating that daily and weekly iron supplementation were both effective in reducing risks. Current evidence indicates that the absorption of supplemental iron is lower in multivitamin and multimineral antenatal supplements than when it is administered alone.
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From page 66... ...
shows that iron supplementation among, poorly nourished, pregnant Indian women reduced anemia prevalence and severity at term, as well as low birthweight, with an odds ratio of 0.3 ]
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From page 67... ...
(1985) reported an additional effect of iron supplementation with vitamin B2 in The Gambia, where the deficiency of this vitamin is endemic.
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From page 68... ...
Research on the importance of certain green leafy vegetables as a source of bioavailable iron is urgently needed, because there is currently not enough information to evaluate the effectiveness of their contribution to improving iron nutrition (de Pee et al., 1996~. Correcting other nutrient deficiencies that may alter iron absorption and metabolism through dietary changes is also a worthwhile measure.
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From page 69... ...
can only be perceived after many months or years and because increments in total dietary iron absorption are moderate (Hulten et al., 1995~. Food Fortification Iron fortification of foods is a preventive measure that aims at improving and sustaining iron nutrition on a permanent basis (Bauernfeind and Lachance, 1991~.
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From page 70... ...
EDTA itself (for example, FeNaEDTA, CaNaEDTA, or Na2EDTA) , at a molar ratio to nonheme iron ~ 1, also enhances iron absorption by a factor of approximately 3 or 4 (MacPhail et al., 1994~.
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From page 71... ...
. This program effectively prevented iron deficiency and increased iron reserves in menstruating adolescent girls attending, school, reducing the proportion of girls with serum ferritin < 20 ~g/1 from 33 to 17 percent.
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From page 73... ...
73 I.~^ o oo _ ~o a~ o ~_ ~5 .
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From page 74... ...
. There are five large studies in developing countries that address the effectiveness of general iron fortification, one each in Thailand, India, South Africa, Guatemala, and Venezuela (Ballot et al., 1989a; Garby and Areekul, 1974; Layrisse et al., 1996; Viteri et al., 1983, l995b; Working Group on Fortification of Salt with Iron, 1982)
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From page 75... ...
Iron administration during pregnancy also reduced the prevalence of serum ferritin values <10 Gal at 36~0 weeks gestation in relation to unsupplemented women (odds ratio 0.05, 95 percent confidence interval 0.02-0.1 1~. Given the clear benefit of iron supplementation during pregnancy to both mother and child among populations where iron deficiency is a serious public health problem, why has this intervention not had more success in reaching the
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From page 76... ...
Current practices of iron supplementation rely almost exclusively on the health care system. Lack of commitment on the part of medical and other health personnel, inadequate operation of the health system, insufficient and inconsistent supplies of the needed supplements, and difficulty =,aini'~g access to medical facilities are all reasons that have been given for low coverage rates of pregnant women.
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From page 77... ...
Preventive supplementation of women of childbearing age before and after pregnancy, through repeated reproductive cycles, offers the best potential for reducing iron deficiency. The historical development of iron supplementation programs and general efforts to control iron deficiency have suffered from several factors: Iron deficiency has no evident and dramatic health effects until it is extremely severe, although its hidden functional and health effects may be more widespread and equally important in their detrimental effects on individual, social, and economic development and well-being.
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From page 78... ...
As a response to these issues, "preventive supplementation" based on a eommunity-eentered regimen of weekly iron doses to populations or groups within populations at risk of developing iron deficiency has been proposed (Viteri 1993, 1994b, 1995~. This proposal originated from animal studies showing that synchronizing the administration of iron supplements Title the turnover of the intestinal mueosa improved the efficiency of iron absorption by a factor of more than 2.5 (Viteri et al., 1995a)
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From page 79... ...
Absorption may be as high as 40 percent or more in irondeficient anemic subjects, providing the equivalent of 3.8 mg/day. The longterm effect would be to correct iron deficiency and increase iron reserves to desired levels (currently found in only 50 percent of women of childbearing age in the United States Cook et al., 1986 and few women in most developing countries)
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From page 80... ...
. bConsidering that in spite of iron fortification and adequate prepregnancy iron reserves, prophylactic iron supplementation will still be recommended during pregnancy.
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From page 81... ...
Short-Term 1. Each country should draw up a plan of action that will lead to the following medium- and long-term goals: The 5-year, medium-term goal: Reduce to one-third the current prevalence estimates of anemia in pregnant women and children from 9 months
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From page 82... ...
These should include the adoption of the concept that pregnancy is a part of the life of mature women, and that it should not be considered in isolation. The chosen plan of action, including the suitable interventions, should be coordinated with efforts to control vitamin A deficiency and other nutritional and relevant health problems that impinge on the iron nutritional situation ofthe population, with emphasis on the pregnant and lactating woman, early childhood, and women of childbearing age.
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From page 83... ...
APPENDIX Five Studies in Developing Countries Addressing the Effectiveness of Iron Fortification The Thai Study Garby and Areekul (1974) evaluated fish sauce fortified with NaFeEDTA to a concentration of 0.5 to 1 mg of iron/ml.
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From page 84... ...
. Iron nutritional status was evaluated in children > 10 years old and adult male and female members of 135 families in a South African community.
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From page 85... ...
The populations studied were previously characterized by iron nutritional status, masala consumption, organoleptie characteristics, and acceptability of the fortified product (Ballot et al, 1989b) , and iron absorption from the added NaFeEDTA (Lamparelli et al., 1987~.
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From page 86... ...
Clinical trials of small-scale fortification had also been conducted satisfactorily, and the absorption of NaFeEDTA-iron and nonheme iron in Guatemalan diets had been measured previously (Viteri et al., 1978~. Experimental studies had also been performed on the stability, acceptability, organoleptic characteristics, and availability of iron and vitamin A in the doubly fortified sugar and on the effect of NaFeEDTA on zinc absorption and turnover in rats.
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From page 87... ...
With few exceptions, iron stores did not change significantly in the control community, but increased progressively in all age and gender groups in the fortified communities. Estimates of total iron absorption based on changes in iron stores fall within those expected from previous iron absorption studies.
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From page 88... ...
The study consisted of an evaluation of the changes in the prevalence of anemia, iron deficiency, and serum ferritin levels that have taken place in crosssectional samples of schoolchildren of low socioeconomic status at the ages of 7, 11, and 15 years between the years 1989 and 1990, and in 1992. In 1994, additional data were obtained from a sample of children in the capital city of Caracas, about 1 year after fortification of both precooked maize flour and white wheat flour was introduced in the country.
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From page 89... ...
Mean estimates of per capita consumption of precooked maize and wheat flour were 80 g/d and 74 g/d. The 1994 evaluation of the Caracas public school population, compared with those performed in 1989-1990 and 1992, should reflect the effect of the iron fortification program in the schoolchildren of the city's lower socioeconomic strata.
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From page 90... ...
1976. Iron supplementation for infants.
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From page 91... ...
Weekly iron supplementation is as effective as 5 per-day iron supplementation in Bolivian schoolchildren living at high altitude.
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From page 92... ...
1996. Comparison of weekly and daily iron supplementation to pregnant women in Guatemala (supervised and unsupervised)
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From page 93... ...
1996. Adherence to iron supplementation during pregnancy in Tanzania: determinants and hematological consequences.
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From page 94... ...
1974. Iron supplementation in Thai fish sauce.
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From page 95... ...
1996. Population Study of Relative Effectiveness of Weekly and Daily Iron Supplementation in Infants and Toddlers.
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From page 96... ...
1987. Curry powder as a vehicle for iron fortification: effects on iron absorption.
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From page 97... ...
1996. The effectiveness of weekly iron supplementation regimen in improving the iron status of Chinese children and pregnant women.
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From page 98... ...
1996. Effects of weekly iron supplementation on pregnant Indonesian women are similar to those of daily supplementation.
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From page 99... ...
biweekly iron supplementation in Indonesian preschool children with low iron status.
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From page 100... ...
1982. Effect of iron supplementation on serum ferritin levels during and after pregnancy.
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From page 101... ...
1997a. Effective iron supplementation does not happen in isolation.
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From page 102... ...
1996a. Weekly iron supplementation of fUrtile-age women achieves a progressive increment in serum ferritin.
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