RESUMO
Biofortification of crops that provide major food staples to large, poor rural populations offers an appealing strategy for diminishing public health problems attributable to micronutrient deficiencies. The objective of this first-stage human study was to determine the increase in quantity of zinc (Zn) absorbed achieved by biofortifying wheat with Zn. Secondary objectives included evaluating the magnitude of the measured increases in Zn absorption as a function of dietary Zn and phytate. The biofortified and control wheats were extracted at high (95%) and moderate (80%) levels and Zn and phytate concentrations measured. Adult women with habitual diets high in phytate consumed 300 g of 95 or 80% extracted wheat as tortillas for 2 consecutive days using either biofortified (41 mg Zn/g) or control (24 mg Zn/g) wheat. All meals for the 2-d experiment were extrinsically labeled with Zn stable isotopes and fractional absorption of Zn determined by a dual isotope tracer ratio technique. Zn intake from the biofortified wheat diet was 5.7 mg/d (72%) higher at 95% extraction (P < 0.001) and 2.7 mg/d (68%) higher at 80% extraction compared with the corresponding control wheat (P = 0.007). Zn absorption from biofortified wheat meals was (mean +/- SD) 2.1 +/- 0.7 and 2.0 +/- 0.4 mg/d for 95 and 80% extraction, respectively, both of which were 0.5 mg/d higher than for the corresponding control wheat (P < 0.05). Results were consistent with those predicted by a trivariate model of Zn absorption as a function of dietary Zn and phytate. Potentially valuable increases in Zn absorption can be achieved from biofortification of wheat with Zn.
Assuntos
Farinha/análise , Alimentos Fortificados/análise , Triticum/química , Zinco/química , Zinco/metabolismo , Adolescente , Adulto , Estudos Transversais , Suplementos Nutricionais , Feminino , Humanos , México , Adulto Jovem , Zinco/urina , Isótopos de ZincoRESUMO
BACKGROUND: Biofortification is an agricultural process that attempts to increase the iron and zinc content of staple food crops. Improving the absorption of zinc and iron could contribute to reducing the high rates of deficiency of these micronutrients in developing-country settings. OBJECTIVE: To simulate the effects of biofortification of staple food crops (maize, wheat, rice, and beans) on the absorption of zinc and iron among women and children in Mexico. METHODS: We analyzed dietary data from the 1999 Mexican National Nutrition Survey. On the basis of the intake of the four staple food crops and the increase in zinc and iron content that could be achieved by conventional breeding in the short term, the prevalence of inadequacy in the amounts of absorbed zinc and iron was determined. The mean increase in the amounts of absorbed zinc and iron was compared according to rural and urban residence and according to region of the country. RESULTS: In rural areas, simulated biofortification of maize resulted in a reduction in the prevalence of absorption of inadequate amounts of zinc of 47% in children and 56% in women but had no effect on the prevalence of absorption of inadequate amounts of iron. The increase in zinc absorption was greater in rural populations and in the Central and Southern regions (p < .05). CONCLUSIONS: Biofortification of maize could significantly improve zinc absorption among children and women in Mexico living in areas most vulnerable to zinc deficiency. Studies of the biological impact of biofortified maize on zinc status are warranted.
Assuntos
Alimentos Fortificados , Ferro/farmacocinética , Desnutrição/dietoterapia , Modelos Biológicos , Zinco/farmacocinética , Absorção , Adulto , Anemia Ferropriva , Pré-Escolar , Coleta de Dados/métodos , Grão Comestível , Feminino , Humanos , Ferro/uso terapêutico , Deficiências de Ferro , Masculino , México , Inquéritos Nutricionais , Zinco/deficiência , Zinco/uso terapêuticoRESUMO
BACKGROUND: Universal fortification of staple foods with iron has been widely promoted as a cost-effective strategy to reduce iron deficiency in developing-country populations. Nonetheless, relatively few efficacy trials have been reported to date to demonstrate impact on iron status. The Ultra Rice technology provides a means of delivering fortificant iron via rice. OBJECTIVE: The objective of this study was to test the efficacy of rice fortified with microencapsulated, micronized iron pyrophosphate to improve the iron status of women in Mexico in a randomized, controlled intervention trial. METHODS: Nonpregnant, nonlactating women 18 to 49 years of age were recruited from six factories. The women received a daily portion of cooked rice 5 days per week for a period of 6 months, before and after which iron status indicators were determined in venous blood samples. RESULTS: The average intake of iron from the fortificant was 13 mg/day. Mean plasma ferritin concentration and estimated body iron stores were significantly higher, and transferrin receptors were lower, in the iron-fortified rice group following the intervention. Mean hemoglobin concentration also increased in the treatment group, but the increase was significant only when the analysis was restricted to those with baseline hemoglobin < 12.8 g/dL. The absolute reduction in anemia and iron deficiency was 10.3 and 15.1 percentage points, respectively. Total iron intake from fortificant was a significant covariate of change in body iron stores. The overall prevalence of anemia was reduced by 80%. CONCLUSIONS: Fortification of rice with iron using this technology is an efficacious strategy for preventing iron deficiency.
Assuntos
Anemia Ferropriva/tratamento farmacológico , Alimentos Fortificados , Hemoglobinas/metabolismo , Ferro da Dieta/uso terapêutico , Estado Nutricional , Oryza , Adolescente , Adulto , Anemia Ferropriva/sangue , Anemia Ferropriva/epidemiologia , Anemia Ferropriva/prevenção & controle , Difosfatos/administração & dosagem , Difosfatos/uso terapêutico , Feminino , Ferritinas/sangue , Hemoglobinas/efeitos dos fármacos , Humanos , Ferro/administração & dosagem , Ferro/uso terapêutico , Ferro da Dieta/administração & dosagem , México/epidemiologia , Pessoa de Meia-Idade , Prevalência , Receptores da Transferrina/metabolismo , Resultado do TratamentoRESUMO
The objective of this study was to estimate the amount of bioavailable iron (FeBIO) in the diet of Mexican children aged 12-59 mo through the application of algorithms that use dietary variables and analyze the association between estimated FeBIO and hemoglobin (Hb) concentration. Data were analyzed for 919 children aged 12-59 mo old who participated in a national probabilistic survey on nutrition, in which a 24-h dietary recall was applied and Hb concentration was determined through the use of portable photometers. Dietary intakes were determined for total iron, heme and nonheme iron, vitamin C, phytates, and meat (red meat, poultry, and fish). Using these dietary variables and distinct scenarios on body iron reserves, we used algorithms to estimate the amount of FeBIO in the diet. Linear regression models were adjusted to evaluate the association between FeBIO and Hb. The mean iron intake was 6.2 +/- 4.4 mg/d and the mean estimated FeBIO ranged between 0.14 and 0.37 mg/d depending on different assumptions about iron reserves, representing 2.7-6.1% of total iron intake. The Hb concentration, adjusted for altitude and presence of diarrhea, was positively associated with FeBIO in children 12-23 mo old (P < 0.05) but not in children 24-59 mo old. The estimated FeBIO is low in relation to physiological requirements and is compatible with existing high iron deficiency prevalence rates in Mexico. Although Hb is not a specific indicator of iron status, it was significantly associated with FeBIO.
Assuntos
Anemia/sangue , Hemoglobinas/metabolismo , Ferro da Dieta/farmacocinética , Disponibilidade Biológica , Pré-Escolar , Humanos , Lactente , MéxicoRESUMO
OBJECTIVE: To describe supplement use practices among non-pregnant, non-lactating Mexican women (12-49 y) and estimate their impact on the proportion of women with intakes below the Estimated Average Requirement (EAR) and above the Upper Limit (UL) using data from a national probabilistic nutrition survey in Mexico (1999). METHODS: Information was collected by questionnaire on the frequency and duration of supplement use in the previous 6 months (n = 17,794). Dietary intakes by 24-hour recall were determined in a representative sub-sample (n = 2,599). Frequency of use and available information on the nutrient content of supplements was used to estimate daily equivalent intakes. RESULTS: 17.6% of women reported to have used supplements. The majority of these took supplements once daily (71%) and for < or =2 months (75%). While nutrient intakes from diet alone did not differ between users and non-users, the proportion with intakes of Vitamins A, B(6), B(12), and C, folate, iron, and zinc < EAR were significantly greater among the supplement non-users when intakes from supplements were also considered. The proportion of women with intakes > UL was greater among supplement users than non-users for iron, folate and Vitamin B(6). CONCLUSION: Supplement use contributes to the adequacy of nutrient intakes but may also increase the possible risk of toxic intakes of some nutrients among Mexican women.
Assuntos
Suplementos Nutricionais/estatística & dados numéricos , Minerais/administração & dosagem , Política Nutricional , Necessidades Nutricionais , Vitaminas/administração & dosagem , Adolescente , Adulto , Criança , Estudos Transversais , Feminino , Humanos , Rememoração Mental , México , Pessoa de Meia-Idade , Inquéritos NutricionaisRESUMO
UNLABELLED: BACKGROUND. Optimal feeding of infants and young children in developing countries includes daily feeding of animal-source foods. OBJECTIVE. To evaluate constraints on the availability of animal-source foods at the community level, access to animal-source foods at the household level, and intake of animal-source foods at the individual level among children under 3 years of age in case studies in five developing countries: Mexico, Peru, Haiti, Senegal, and Ethiopia. METHODS: Data were obtained from published and unpublished research and from program experiences of health and agriculture specialists. RESULTS: In Ethiopia, 27% to 51% of case-study children had consumed an animal-source food on the previous day; from 56% to 87% of children in the other case-study sites had consumed an animal-source food on the previous day. Data on intake of animal-source foods in grams were only available for the Latin American case-study sites, where daily milk intake was high in Mexico and Peru (195 and 180 g/day, respectively) and the intakes of meat, fish, and poultry (MFP) (29.0 and 13.6 g/day) and of egg (18.4 and 4.9 g/day) were low. The conceptual model guiding this work identified more constraining factors at the community and household levels than at the individual level. The most common constraints on feeding animal-source foods to young children were poverty, animal health, and land degradation at the community level; cost of animal-source foods and limited livestock holdings at the household level; and caregivers' perceptions of giving animal-source foods to children at the individual level. CONCLUSIONS: For program planning, it is useful to simultaneously consider factors that affect community availability of household access to, and children's intake of animal-source foods. Efforts to overcome individual-level constraints on intake of animal-source foods should be coupled with activities to address community and household constraints.
Assuntos
Laticínios , Dieta , Abastecimento de Alimentos , Carne , Adolescente , Adulto , Animais , Fenômenos Fisiológicos da Nutrição Infantil , Pré-Escolar , Países em Desenvolvimento , Etiópia , Feminino , Haiti , Humanos , Lactente , Masculino , México , Pessoa de Meia-Idade , Valor Nutritivo , Peru , Pobreza , SenegalRESUMO
The fortification of staple foods with zinc may play an important role in achieving adequate zinc intakes in countries at risk of zinc deficiency. However, little is known about the relative bioavailability of different zinc compounds that may be used in food fortification. The objective of this study was to measure and compare fractional zinc absorption from a test meal that included a maize tortilla fortified with zinc oxide, zinc sulfate, zinc oxide + EDTA, or sodium-zinc EDTA. A double isotopic tracer ratio method ((67)Zn as oral tracer and (70)Zn as intravenous tracer) was used to estimate zinc absorption in 42 Mexican women living in a periurban community of Puebla State, Mexico. The test meal consisted of maize tortillas, yellow beans, chili sauce, and milk with instant coffee; it contained 3.3 mg zinc and had a phytate:zinc molar ratio of 17. Fractional zinc absorption did not differ significantly between the test groups (ANOVA; P > 0.05). Percent absorptions were (mean +/- SD) zinc oxide, 10.8 +/- 0.9; zinc sulfate, 10.0 +/- 0.02; zinc oxide + EDTA, 12.7 +/- 1.5; and sodium-zinc EDTA, 11.1 +/- 0.7. We conclude that there was no difference in zinc absorption from ZnO and ZnSO(4) when added as fortificants to maize tortillas and consumed with beans and milk. The addition of EDTA with zinc oxide or the use of prechelated sodium-zinc EDTA as fortificants did not result in higher zinc absorption from the test meal.
Assuntos
Alimentos Fortificados , Absorção Intestinal , Zea mays , Óxido de Zinco/metabolismo , Sulfato de Zinco/metabolismo , Zinco/metabolismo , Quelantes , Dieta , Ácido Edético , Humanos , México , Sódio , Zinco/urinaRESUMO
BACKGROUND: The risk of zinc deficiency in populations can be estimated by comparing serum zinc data with statistically defined lower cutoffs derived from a presumably healthy population. Serum zinc data are available from a large sample of the US population assessed during the second National Health and Nutrition Examination Survey (NHANES II). Although the original analysis of these data considered fasting status and the time of day of blood sampling, it did not account for potentially confounding variables that may affect the serum zinc concentration, such as age, sex, and health status. OBJECTIVE: The objective was to describe variations in serum zinc concentration by age, sex, and other characteristics and to recommend lower cutoffs for presumably healthy persons. DESIGN: Serum zinc data from NHANES II were analyzed by using analysis of variance and covariance models to identify and describe variables significantly associated with serum zinc concentration; 2.5th percentile curves were produced and used to establish age- and sex-based lower cutoffs. RESULTS: Age and sex were significant confounders of serum zinc concentration, so separate lower cutoffs were derived for children and adolescent and adult males and females. Other minor confounding variables were identified. Tentative lower cutoffs for pregnancy and oral contraceptive use were also derived. CONCLUSIONS: The interpretation of population serum zinc data with the use of lower cutoffs should account for the age and sex of the subjects, pregnancy and oral contraceptive use, and fasting status and time of day of blood collection.
Assuntos
Vigilância da População , Zinco/sangue , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Fatores de Confusão Epidemiológicos , Jejum , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Inquéritos Nutricionais , Estado Nutricional , Estados UnidosRESUMO
This paper describes the proceedings of a workshop that was convened at the 11th International Symposium on Trace Elements in Man and Animals (TEMA-11) symposium to review recent advances concerning the assessment of the trace element status of individuals and populations, using zinc and copper as the primary examples to illustrate basic principles and recent advances in assessment methods. The workshop was initiated with a brief review of the importance of zinc nutriture for human health and a discussion of the likely common occurrence of zinc deficiency worldwide. This overview was followed by presentations on selected issues concerning the assessment of zinc status, with particular attention devoted to dietary assessment techniques, the use of isotopic tracers to assess zinc homeostasis and the relationship of these methods to biochemical indicators of zinc status. Because relatively little information is available on zinc toxicity, the discussion concerning the definition of excess intake of trace elements focused primarily on recent work concerning risk assessment of copper toxicity.