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Instituto de Investigación Nutricional, Lima, Peru and * University of North Carolina, Chapel Hill, NC
4To whom correspondence should be addressed.
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ABSTRACT |
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 TOP ABSTRACT INTRODUCTIONRESEARCH DESIGN AND METHODSRESULTSDISCUSSIONREFERENCES |
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KEY WORDS: • iron deficiency anemia • dietary iron • adolescents
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INTRODUCTION |
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TOPABSTRACTINTRODUCTIONRESEARCH DESIGN AND METHODSRESULTSDISCUSSIONREFERENCES |
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,
Murphy et al. 1986
). In adolescent girls, it can have an
adverse effect on educational performance, productivity and
well-being. Preventing iron deficiency and increasing iron stores
in adolescent girls can improve their iron status in preparation for
pregnancy and benefit their current health and well-being.
Peru has high rates of iron deficiency anemia. From a 1996 national
survey, the prevalence in nonpregnant women of fertile age is 35%
(Demographic and Health Surveys 1997
). A study
by Zavaleta (personal communication) found that 24.7% of adolescent
girls from low income families participating in community kitchens in
periurban Lima were anemic. In a second study (Zavaleta et al., 2000
), the prevalence ranged from 9.9–12% in girls from four
schools in Lima of different socioeconomic levels.
The major cause of anemia in this population is low dietary iron
intake. Strategies for reducing anemia include supplementation,
fortification and improving the diet. Stoltzfus (1993)
postulated that improving iron bioavailability of diets may have a
greater effect than increasing the total quantity of dietary iron
consumed. In many developing countries, access to iron-rich foods
and/or iron absorption–enhancing foods such as fruits and vegetables
is limited and other strategies are necessary. Although Peruvian diets
are typically low in bioavailable iron, in periurban Lima, less
expensive heme sources of iron (e.g., chicken offal, blood and fish),
beans and sources of vitamin C are available throughout the year. Thus
dietary modifications to improve iron status using locally available
foods (Layrisse and García-Casal 1997
) are
possible.
This paper reports on a community-based, randomized behavioral and dietary intervention trial to improve dietary iron intake, iron bioavailability and iron status among adolescent girls in Lima, Peru. The intervention was conducted through local community kitchens (CK)5 in control and intervention periurban populations of Lima. Formative research assessment formed the basis of the intervention, which consisted of an educational campaign to improve the menus of the community kitchens to provide low cost heme iron sources and the promotion of dietary enhancers (i.e., vitamin C with the meal). The strategy also included motivating adolescent girls to understand their nutritional vulnerability and to improve their diets to benefit their health and well-being.
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RESEARCH DESIGN AND METHODS |
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TOPABSTRACTINTRODUCTIONRESEARCH DESIGN AND METHODSRESULTSDISCUSSIONREFERENCES |
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Girls (n = 72) were enrolled initially for the baseline evaluation in the intervention group and 66 in the control; of these, 71 and 50, respectively, accepted having their blood taken and were included in the cohort. In the final evaluation, six girls were lost to follow-up in the intervention group and eight from the control group.
In the formative research stage, in-depth interviews were conducted with 16 girls (two randomly selected from each of the CK) on topics relating to their perceptions of food and nutrition, health and anemia. The interviews were recorded and the expanded notes analyzed by topic using dtSearch Software (Arlington VA).
On the basis of the results of the formative research, an educational campaign was designed and implemented for a period of 9 mo; the intervention consisted of participatory training sessions with the adolescent girls and the CK leaders. Iron-rich menus were developed with the CK members. During the first 5 mo, increased accessibility to less expensive sources of heme iron (chicken liver and blood) was facilitated at cost price from a commercial chicken producer. Educational materials included an attractive school folder, pencil case and T-shirt for the adolescents, promoting the relationship between consuming iron-rich foods and iron enhancers and school performance. Posters, recipe booklets and a mobile promoting iron-rich foods were materials used in the CK.
The effect of the intervention was evaluated by estimating dietary
intake before and after the education intervention using a quantitative
dietary 24-h recall methodology conducted on two successive days by
trained nutritionists. The evaluation was conducted during the months
of June to August 1996 before the intervention and in the same months
in 1997 after the intervention to ensure similar seasonal food
availability. Food intake was converted to nutrients using Peruvian
food composition tables (Instituto de Investigación Nutricional 1998
) and including food composition data from
other Latin American and United States tables where necessary. Mean
intakes were calculated by averaging the nutrient intake for two
consecutive days for each girl and then calculating the mean for all
girls in each study group.
Bioavailable dietary iron was calculated using the algorithm of
Tseng et al. (1997)
in which absorbable iron is
calculated for each meal. Heme iron absorption was assumed to be 25%,
due to the presence of iron deficiency in this population. An
adaptation of the formula of Tseng et al. (1997)
was
used for calculating the bioavailability of nonheme iron, including
enhancer factors, ascorbic acid and flesh food protein, and tea and
infusions as an inhibitor factor. The inhibiting potential of phytate
was not included in the calculation because of the lack of available
data from local food tables.
Iron status was evaluated by blood hemoglobin (Hb) and serum ferritin (SF). Hb was analyzed using the cyanomethemoglobin method. SF was measured according to the RIA method (double antibody Ferritin 125I RIA) using a commercial kit. The use of this method for serum was compared with ELISA from a subsample of nine adolescent girls, yielding a correlation of R2 = 0.997. Anemia in girls was defined as Hb<120 g/L and iron deficiency as SF levels <12.0 µg/L.
Socioeconomic characteristics, knowledge and exposure to the campaign were evaluated by questionnaire. Heights and weights were obtained before and after the intervention.
Descriptive statistics were calculated for each variable for baseline and postintervention data, and comparisons made between study groups. Paired comparisons were made between pre-and postintervention data for each study group. The Mann-Whitney nonparametric test was used to test the hypothesis that the medians of the variables of interest between independent groups were different. The Wilcoxon test was used for paired comparisons in which the variables did not have a normal distribution.
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RESULTS |
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TOPABSTRACTINTRODUCTIONRESEARCH DESIGN AND METHODSRESULTSDISCUSSIONREFERENCES |
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Foods were selected for promotion on the basis of availability, accessibility, acceptability, and cost-nutritional benefit. The "best buys" for iron included blood, spleen, beans and liver. For vitamin C, the "best buys" included oranges, papaya, cabbage, mandarin orange and lemon.
As a result of a behavioral analysis, in which each behavior was evaluated for potential nutritional effect and feasibility of adoption, the primary dietary recommendations selected for the intervention were to increase heme iron food sources in stews prepared in the CK and increase consumption of vitamin C–rich salads and/or drinks with meals containing nonheme iron sources (mostly beans).
No differences were found between the intervention and control groups at baseline on sociodemographic characteristics or dietary intake. Knowledge regarding what foods to eat to improve iron status was higher in the intervention group, particularly with respect to key messages referring to the timely preparation of vitamin C–containing drinks and salads and their consumption with beans at meal times.
Total daily iron intake increased significantly in the intervention
group (P < 0.01) from 7.75 ± 3.5 to 9.42
± 5.0 mg/d after the campaign, whereas in the control group there
was no change (Fig. 1
). Interestingly, intake of heme iron tripled in the intervention group,
from 0.21 ± 0.17 to 0.66 ± 1.35 mg/d, and was significantly
higher than that of the control group after the campaign (Fig. 2
). There was also a significant increase in total ascorbic acid intake
from 44 ± 39.6 to 67 ± 45 mg/d in the intervention group,
with no change in the control group (41 ± 34.6 pre and 40 ± 27.6 mg/d post). There was a small but significant increase in
absorbable iron intake (Fig. 3
) in the intervention group, from 0.33 ± 0.16 pre to 0.43 ± 0.41 mg/d post, with no change in the control group: 0.35 ± 0.13
pre to 0.37 ± 0.22 mg/d post.
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DISCUSSION |
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TOPABSTRACTINTRODUCTIONRESEARCH DESIGN AND METHODSRESULTSDISCUSSIONREFERENCES |
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).
The change in knowledge had a positive effect on behavior; dietary iron
intake improved, whereas it did not in the control community. Although
the behavioral change was significant, it was small; iron intakes were
still low, and absorbable iron, even without adjusting for phytate, was
still well below recommended intakes after the intervention. However,
the results showed an encouraging trend in the adoption of the
recommended practices. The 9-mo intervention period was not sufficient to improve hemoglobin levels significantly. Nevertheless, there appeared to be a protective effect from the intervention in maintaining the iron status of the girls in comparison with the control group.
This study shows that dietary change to improve iron intake is possible in this sample of adolescent girls. A multidietary strategy using an educational campaign combined with identifying and promoting best buys for iron is required to increase consumption of animal sources of iron and vegetable sources with iron absorption enhancers such as vitamin C. These strategies are potentially applicable in urban populations such as Lima where 70% of the country’s population is located and access to a variety of cheaper sources of these nutrients is possible. The results from this study with the adolescent girls was extremely encouraging. The education campaign and materials used captured the girls’ interest and stimulated their motivation to influence their health, nutrition and diet. The potential of applying this experience through schools and other organizations reaching adolescent girls provides an exciting and feasible opportunity.
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ACKNOWLEDGMENTS |
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FOOTNOTES |
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2 This publication was made possible in part through support provided by the Office of Health and Nutrition, USAID, under terms of contract no. HRN-C-00-93-00038-00, and the MotherCare Project, John Snow, Incorporated (JSI). The contents and opinions expressed herein are those of the authors and do not necessarily reflect the view of USAID or JSI.
3 The project was approved by the Ethics committee of the Instituto de Investigación Nutricional, number 081–95/CEI.
5 Abbreviations used: CK, community kitchen; Hb, hemoglobin; SF, serum ferritin.
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REFERENCES |
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TOPABSTRACTINTRODUCTIONRESEARCH DESIGN AND METHODSRESULTSDISCUSSIONREFERENCES |
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1. Demographic and Health Surveys (1997) Encuesta Demográfica y de Salud Familiar 1996. Instituto Nacìonal de Estadística e Informática. Lima, Peru. Macro International Inc., Calverton, MD.
2. Garn S. M., Ridella S. A., Petzold A. S., Folkner F. Maternal hematologic levels and pregnancy outcomes. Semin. Perinatol 1981;5:155-162[Medline]
3. Instituto de Investigación Nutricional Tabla de composición de alimentos 1998 Lima Perú.
4. Kanani S. Combate de la anemia en niñas adolescentes: informe de la India. Bol. Alim. Inf. Nutr. Mat. 1994;13:1-3
5. Layrisse M., García-Casal M. N. Strategies for the prevention of iron deficiency through foods in the household. Nutr. Rev. 1997;55:233-239[Medline]
6. Murphy J. F., O’Riordam J., Pearson J. F. Relation of hemoglobin levels in first and second trimesters to outcome of pregnancy. Lancet 1986;1:992-994[Medline]
7. Stoltzfus R. Iron deficiency and strategies for its control 1993 Report prepared for Office of Nutrition AID.
8.
Tseng M., Chakraborty H., Robinson D. T., Mendez M., Kohlmeier M. Adjustment of iron intake for dietary enhancers and inhibitors in population studies: bioavailable iron in rural and urban residing rural women and children. J. Nutr. 1997;127:1456-1468
9. Zavaleta, N., Respicio, G., & Garcia, T. (2000). Efficacy of an intermittent iron dose compared to daily iron supplementation in adolescent girls. J. Nutr. (in press).
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