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1.
J Am Coll Nutr ; 18(3): 213-22, 1999 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10376776

RESUMO

OBJECTIVE: To determine whether supplementation of vitamin A and/or zinc (Zn) improved serum levels of these nutrients and/or height and weight gains in preschool children, 22 to 66 months, living in Belize, Central America. METHODS: Subjects received either Zn, vitamin A, Zn and vitamin A or a placebo, (70 mg Zn and/or 3030 RE vitamin A, once per week) for 6 months in a 2x2 factorial design. Forty-three children, from a population of 104 prescreened, completed the study; they were selected, prior to treatment, for low/marginal serum concentrations of these micronutrients. RESULTS: Serum Zn levels were greater (16%, p<0.001) for those who received Zn. In contrast, after vitamin A treatment there were no differences in serum vitamin A among groups. Although increases in height (+4.4 cm, p<0.001) and weight (+0.79 kg, p<0.001), compared with baseline values, were numerically greatest for children who received both supplements, only the vitamin A supplementation effect was significant, resulting in increased height (+1.4 cm, p<0.002) and greater weight gain (+0.15 kg, p<0.03) compared to those receiving no vitamin A. Vitamin A supplementation alone significantly increased (p<0.001) hemoglobin concentration. CONCLUSION: The results suggest that the preschool children in this study, prescreened for low/marginal serum concentrations from a larger population prior to treatment, were enduring inadequate vitamin A and, to a lesser degree, Zn nutriture. Height and weight gain were significantly increased in the subjects who received a single weekly supplement 3030 RE of vitamin A.


Assuntos
Estatura/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Suplementos Nutricionais , Vitamina A/administração & dosagem , Vitamina A/sangue , Zinco/administração & dosagem , Zinco/sangue , Belize , Criança , Pré-Escolar , Cromatografia Líquida de Alta Pressão , Método Duplo-Cego , Combinação de Medicamentos , El Salvador/etnologia , Hemoglobinas/efeitos dos fármacos , Humanos , Refugiados
2.
J Am Coll Nutr ; 18(3): 213-22, Jun. 1999.
Artigo em Inglês | MedCarib | ID: med-1348

RESUMO

OBJECTIVE: To determine whether supplementation of vitamin A and/or zinc (Zn) improved serum levels of these nutrients and/or height and weight gains in preschool children, 22 to 66 months, living in Belize, Central America. METHODS: Subjects received either Zn, vitamin A, Zn and vitamin A or a placebo (70 mg Zn and/or 3030 RE vitamin A, once per week) for 6 months in a 2x2 factorial design. Forty-three children, from a population of 104 prescreened, completed the study; they were selected, prior to treatment, for low/marginal serum concentrations of these micronutrients. RESULTS: Serum Zn levels were greater (16 percent, p < 0.001) for those who received Zn. In contrast, after vitamin A treatment, there were no differences in serum vitamin A among groups. Although increases in height (+4.4 cm, p<0.001) and weight (+0.79 kg, p<0.001), compared with baseline values, were numerically greatest for children who received both supplements, only the vitamin A supplementation effect was significant, resulting in increased height (+1.4 cm, p<0.002) and greater weight gain (+0.15 kg, p<0.03) compared to those receiving no vitamin A. Vitamin A supplementation alone significantly increased (p<0.001) hemoglobin concentration. CONCLUSION: The results suggest that the preschool children in this study, prescreened for low/marginal serum concentrations from a larger population prior to treatment, were enduring inadequate vitamin A and, to a lesser degree, Zn nutriture. Height and weight gain were significantly increased in the subjects who received a single weekly supplement 3030 RE of vitamin A.(Au)


Assuntos
Criança , Pré-Escolar , Estudo Comparativo , Humanos , Estatura/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Suplementos Nutricionais , Vitamina A/administração & dosagem , Vitamina A/sangue , Zinco/administração & dosagem , Zinco/sangue , Cromatografia Líquida de Alta Pressão , Método Duplo-Cego , Combinação de Medicamentos , El Salvador/etnologia , Hemoglobinas/efeitos dos fármacos , Refugiados
3.
Am J Clin Nutr ; 64(5): 726-30, 1996 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-8901792

RESUMO

Suggestions that carotenoid-containing foods are beneficial in maintaining health have led to several studies of circulating carotenoid concentrations of adults. Because few data are available for children, we report serum carotenoid concentrations of 493 children in Belize. Carotenoid concentrations were determined as part of a survey of vitamin A status of children, most between 65 and 89 mo of age. Reproducibility was tested by collecting a second blood sample 2 wk after the first collection from a subset of children (n = 23) who consumed their habitual diet with no treatment during the interim. Predominant serum carotenoids were lutein/zeaxanthin and beta-carotene, which accounted for 26% and 24% of median total carotenoids, respectively. The three provitamin A carotenoids, alpha- and beta-carotene and beta-cryptoxanthin, constituted 51% of median total carotenoid concentrations. Partial correlations of each carotenoid with fasting retinol concentration indicated that beta-carotene had the highest correlation. Concordance correlation coefficients (rc) for fasting carotenoid concentrations determined 2 wk apart were > or = 0.89 for lycopene, beta-cryptoxanthin, and alpha- and beta-carotene. The rc for lutein/zeaxanthin and total carotenoids was lower, 0.59 and 0.68, respectively, because of higher lutein/zeaxanthin concentrations at the second sampling than at the first. The reproducibility of the concentrations suggests both that individuals have characteristic profiles and that serum carotenoid concentrations can be measured randomly over > or = 2 wk without significant bias.


Assuntos
Carotenoides/sangue , Belize/epidemiologia , Criança , Pré-Escolar , Cromatografia Líquida de Alta Pressão , Criptoxantinas , Dieta/normas , Humanos , Luteína/sangue , Licopeno , Reprodutibilidade dos Testes , Vitamina A/sangue , Vitamina A/uso terapêutico , Deficiência de Vitamina A/sangue , Deficiência de Vitamina A/tratamento farmacológico , Deficiência de Vitamina A/epidemiologia , Xantofilas , beta Caroteno/análogos & derivados , beta Caroteno/sangue
4.
Am J Clin Nutr ; 64(5): 726-30, Nov. 1996.
Artigo em Inglês | MedCarib | ID: med-2489

RESUMO

Suggestions that carotenoid-containing foods are beneficial in maintaining health have led to several studies of circulating carotenoid concentrations of adults. Because few data are available for children, we report serum carotenoid concentrations of 493 children in Belize. Carotenoid concentrations were determined as part of a survey of vitamin A status of children, most between 65 and 89 mo of age. Reproducibility was tested by collecting a second blood samples 2 wk after the first collection from a subset of children (n = 23) who consumed their habiitual diet with no treatment during the interim. Predominant serum carotenoids were lutein/zeaxanthin and beta-carotene, which accounted for 26 percent and 24 percent of median total carotenoids, respectively. The three provitamin A carotenoids, alpha- and beta-carotene and beta-cryptoaxnthin, constituted 51 percent od median total carotenoid concentrations. Partial correlations of each carotenoid with fasting retinol concentrations indicated that beta-carotene had the highest correlation. Concordance correlation coefficients (rc) for fasting carotenoid concentrati9ons determined 2 wk apart were > or = 0.89 for lycopene, beta-cryptoxanthin, and alpha- and beta-catotene. The rc for lutein/zeaxanthin and total carotenoids was lower, 0.59 and 0.68, respectively, because of higher lutein/zeaxanthin concentrations at the second sampling than at the first. The reproducibility of the concentrations suggest both that individuals have characteristic profiles and that serum carotenoid concentrations can be measured randomly over > or =2 wk without significant bias. (au)


Assuntos
Criança , Pré-Escolar , Humanos , Carotenoides/sangue , Carotenoides/sangue , Carotenoides/sangue , Cromatografia Líquida de Alta Pressão , Dieta/normas , Vitamina A/sangue , Vitamina A/uso terapêutico , Deficiência de Vitamina A/sangue , Deficiência de Vitamina A/tratamento farmacológico , Deficiência de Vitamina A/epidemiologia , Luteína/sangue
5.
J Am Coll Nutr ; 15(5): 439-49, 1996 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-8892169

RESUMO

OBJECTIVE: A study of children (2-8 years; n = 613) in Belize, Central America, was conducted to determine what proportion of the children might be at risk of vitamin A (vit A) deficiency. The data provide an opportunity to compare results of three methods of assessing vit A status in a population which was not severely malnourished. Serum retinyl ester concentrations were also determined; their relevance to one of the tests, the relative dose response (RDR) test, is discussed. METHODS: The three methods of assessing vit A status were: RDR test, fasting serum retinol concentration, and conjunctival impression cytology (CIC). Retinol-binding protein (RBP), serum retinyl esters and serum zinc concentrations were also determined. RESULTS: Inadequate vit A status was indicated for 17% of subjects by the RDR test (14% cutoff), for 24% by fasting serum retinol concentration (< 0.87 mumol/L), and for 49% by "abnormal" CIC score. Retinyl esters constituted 24% of serum retinoids at the time (5 hours after a retinyl palmitate dose) at which the second blood sample is taken for the RDR test. Regression tree analyses (CART) indicated ethnicity was a predictor of RDR score; ethnicity, stunting and age were predictors of fasting serum retinol concentration; ethnicity and stunting were predictors of 0-hour retinyl ester concentration. CONCLUSION: The three indices of vit A status did not identify the same individuals nor indicate the same percentage of the population to be at risk for vit A deficiency. Increased concentrations of retinyl esters at 5 hours compared to those at 0 hours suggest that insufficient retinol may have been taken up by the liver at 5 hours to release all accumulated retinol-binding protein (RBP) in deficient individuals; prevalence of vit A deficiency might therefore be underestimated by the RDR test. The selection of ethnicity as a predictor of RDR score and of 0-hour retinol and retinyl ester concentrations suggests that factors other than vit A status affect vit A metabolism and may affect the RDR test.


Assuntos
Estado Nutricional , Vitamina A/sangue , Belize , Criança , Pré-Escolar , Cromatografia Líquida de Alta Pressão , Etnicidade , Feminino , Humanos , Masculino , Fatores de Risco , Zinco/sangue
6.
J Am Coll Nutr ; 15(5): 450-7, 1996 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-8892170

RESUMO

OBJECTIVE: Reproducibility of the relative dose response test (RDR), a test designed to measure vitamin A status, was tested in 23 Belizean children, 5-8 years after 2-week interval during which no treatment was given. METHODS: As required for the RDR test, serum retinol concentrations were determined before and 5 hours after an oral dose of vitamin A. An RDR score > 14% was used as the criterion of inadequate vitamin A status. The HPLC method used to measure serum retinol concentrations also determined the concentrations of four retinyl esters. RESULTS: The RDR test was reproducible for 17 of 23 subjects: 3 scored > 14% on both tests; 14, < 14% on both. Six subjects scored > 14% on only one test. The concordance correlation coefficient (rc) for the percent change in the two tests was 0.24; for fasting serum retinol concentration, rc = 0.81. For retinyl palmitate and stearate, the esters present in highest concentrations at 5 hours, concordance correlation coefficients were 0.75 and 0.59, respectively. CONCLUSION: The failure of the RDR test to classify 26% of the subjects reproducibly reduces the usefulness of the test. In addition, the reproducibility of the retinyl ester concentrations in serum 5 hours after the retinyl palmitate dose and the relatively high concentrations in some subjects suggests that some individuals may not metabolize sufficient retinol in 5 hours to cause a maximal increase in serum retinol, resulting in an underestimation of deficiency in a population in which the RDR test is used.


Assuntos
Anticarcinógenos/sangue , Vitamina A/análogos & derivados , Vitamina A/sangue , Criança , Pré-Escolar , Cromatografia Líquida de Alta Pressão , Diterpenos , Relação Dose-Resposta a Droga , Feminino , Humanos , Masculino , Reprodutibilidade dos Testes , Ésteres de Retinil , Vitamina A/administração & dosagem
7.
J Am Coll Nutr ; 15(5): 439-49, Oct. 1996.
Artigo em Inglês | MedCarib | ID: med-2095

RESUMO

A study of children (2 - 8 years; n = 613) in Belize, Central America, was conducted to determine what proportion of the children might be at risk of vitamin A (vit A) deficiency. The data provide an opportunity to compare results of three methods of assessing vit A status in a population which was not severely malnourished. Serum retinyl ester concentrations were also determined; their relevance to one of the tests, the relative dose response (RDR) test, is discussed. METHODS: The three methods of assessing vit A status were: RDR test, fasting serum rintol concentration, and conjunctival impression cytology (CIC). Retinol-binding protein (RBP), serum retinyl esters and serum zinc concentrations were also determined. RESULTS: Inadequate vit A status was indicated for 17 percent of subjects by the RDR test (14 percent cutoff), for 24 percent by fasting serum retinol concentration (< 0.87 mumol/L), and for 49 prcent by abnormal. CIC score. Retinyl esters constituted 24 percent of serum retinoids at the time (5 hours after a retinyl palmitate dose) at which the second blood sample is taken for the RDR test. Regresssion trees analyses (CART) indicated ethnicity was a predictor of RDR score; ethnicity, stunting and age were predictors of fasting serum retinol concentration; ethnicity and stunting were predictors of O-hour retinyl ester concentration. CONCLUSION: The three indices of vit A status did not identify the same individuals nor indicate the same percentage of the population to be at risk for hours compared to those at O hours suggest that insufficient retinol may have been taken up by the liver at 5 hours to release all accumulated retinol-binding protein (RBP) in deficient individuals; prevalence of vit A deficiency might therefore be underestimated by the RDR test. The selection of ethnicity as a predictor of RDR score and of O-hour retinol and retinyl ester concentrations suggests that factors other than vit A status affect vit A metabolism and may affect the RDR test.(AU)


Assuntos
Estudo Comparativo , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Estado Nutricional , Vitamina A/sangue , Belize , Cromatografia Líquida de Alta Pressão , Etnicidade , Fatores de Risco , Zinco/sangue
10.
Am J Clin Nutr ; 30(12): 2033-40, 1977 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-930873

RESUMO

Two groups of 10 healthy young men were matched on the basis of their free-choice consumptions of regular table salt. For 28 days they were then fed carefully controlled low-sodium foods. One group was permitted free-choice seasoning of these foods with regular table salt, the other with a 1:1 mixture of sodium and potassium chlorides. Intakes and urinary and fecal excretions of sodium and potassium were determined by analysis. The results were: 1) the subjects salted their food with essentially the same amounts of regular table salt as of the 1:1 mixture; 2) the sodium intake associated with seasoning at the table was reduced with the 1:1 mixture to 44 percent of the amount consumed with regular table salt; and 3) over a 28-day period there was no tendency for subjects to increase their use of a 1:1 mixture, when used in place of regular table salt, to compensate for their reduced sodium intakes. Under the conditions of this study, the use of the 1:1 mixture as a seasoning agent for foods that contained no added salt resulted in an average total intake of sodium (food plus seasoning) which was 55 percent that of the subjects using regular table salt.


Assuntos
Cloreto de Potássio , Potássio/metabolismo , Cloreto de Sódio , Sódio/metabolismo , Adulto , Pressão Sanguínea , Condimentos/normas , Dieta Hipossódica , Humanos , Masculino , Pessoa de Meia-Idade
11.
Science ; 197(4309): 1187-9, 1977 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-897661

RESUMO

In rats, gastrointestinal aluminum absorption and tissue distribution were altered by parathyroid hormone; the resultant tissue concentrations were similar to those observed in dialysis patients with a fatal encephalopathy. In dialysis patients, serum aluminum and endogenous parathyroid hormone concentrations are significantly correlated. These data suggest that aluminum toxicity in dialysis patients results from oral aluminum ingestion in the presence of hyperparathyroidism.


Assuntos
Alumínio/metabolismo , Hormônio Paratireóideo/farmacologia , Alumínio/sangue , Animais , Osso e Ossos/metabolismo , Encéfalo/metabolismo , Humanos , Masculino , Músculos/metabolismo , Hormônio Paratireóideo/sangue , Ratos , Diálise Renal
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