Folatos y vitamina B12 en la salud humana / Folate, vitamin B12 and human health

During the past decade the role of folate and vitamin B12 in human nutrition have been under constant re-examination. Basic knowledge on the metabolism and interactions between these essential nutrients has expanded and multiple complexities have been unraveled. These micronutrients have shared functions and intertwined metabolic pathways that define the size of the "methyl donor" pool utilized in multiple metabolic pathways; these include DNA methylation and synthesis of nucleic acids. In Chile, folate deficiency is virtually nonexistent, while vitamin B12 deficiency affects approximately 8.5-51% depending on the cut-off value used to define deficiency. Folate is found naturally mainly in vegetables or added as folic acid to staple foods. Vitamin B12 in its natural form is present only in foods of animal origin, which is why deficit is more common among strict vegetarians and populations with a low intake of animal foods. Poorfolate status in vulnerable women of childbearing age increases the risk of neural tube birth defects, so the critical time for the contribution of folic acid is several months before conception since neural tube closure occurs during the first weeks of life. The absorption of vitamin B12 from food is lower in older adults, who are considered to have higher risk of gastric mucosa atrophy, altered production of intrinsic factor and acid secretion. Deficiency of these vitamins is associated with hematological disorders. Vitamin B12 deficiency can also induce clinical and sub-clinical neurological and of other disorders. The purpose of this review is to provide an update on recent advances in the basic and applied knowledge of these vitamins relative to human health.

Megaloblastic anemia: Back in focus.

Megaloblastic anemia (MA), in most instances in developing countries, results from deficiency of vitamin B12 or folic acid. Over the last two to three decades, incidence of MA seems to be increasing. Of the two micronutrients, folic acid deficiency contributed to MA in a large majority of cases. Now deficiency of B12 is far more common. In addition to anemia, occurrence of neutropenia and/or thrombocytopenia is increasingly being reported. Among cases presenting with pancytopenia, MA stands out as an important (commonest cause in some series) cause. This article focuses on these and certain other aspects of MA. Possible causes of increasing incidence of MA are discussed. Observations on other clinical features like neurocognitive dysfunction, associated hyperhomocysteinemeia and occurrence of tremors and thrombocytosis during treatment are highlighted.

Alterações no metabolismo da homocisteína induzidas por aguardente de cana-de-açúcar em alcoólatras / Homocystein metabolism alterations induced by sugar-cane liquor in alcoholics

O alcoolismo está relacionado a má nutriçäo e baixos níveis de várias vitaminas que fazem parte do metabolismo da homocisteína (Hci). O objetivo deste estudo foi analisar a prevalência de hiper-homocisteinemia em pacientes com alta ingestäo diária de aguardente de cana-de-açúcar. Foram incluídos neste estudo 31 homens hospitalizados para tratamento de alcoolismo. Hci, folato (Fol), vitamina B12 séricos e enzimas hepáticas foram determinados e repetidos após 21 dias de abstinência alcoólica. Os valores de Hci em æmol/l antes e depois do tratamento foram, respectivamente, de 24,88 ± 2,09 e 12,48 ± 0,69. A abstinência alcoólica diminuiu significativamente os valores de aspartato aminotransferase, alanina aminotransferase e gamaglutamiltranspeptidase. Näo houve alteraçäo dos níveis de hemácias, proteínas totais e concentraçäo de hemoglobina corpuscular média. Os níveis de Hci antes do tratamento se correlacionaram com os de folato (r² = 0,333). Estes resultados sugerem que o alcoolismo crônico está acompanhado por perturbaçäo do metabolismo de aminoácidos sulfurados e que a hiper-homocisteinemia etanol-induzida através de aguardente de cana-de-açúcar pode ser acompanhada de níveis séricos baixos de folato, agravando o estado nutricional destes pacientes

Situación de los programa de fortificación de alimentos / Situation of the programs of fortification of food year 2000

El documento presenta la situación de los programas de fortificación de alimentos en el año 2,000 en Nicaragua. La informacion proviene de la II Encuesta Nacional de Micronutrientes. Aunque la información no tiene el rigor estadístico para cada uno de los departamentos. El documento también proporciona datos provenientes de las actividades de inspección realizadas por el Departamento de Control de Alimentos del Ministerio de Salud en el año 2,000, tanto en plantas procesadoras como en sitios de expendios, que aunque sin seguir un patrón sistématico y periódico, es información útil e importante de ser conocida

Pancytopenia in a pregnant woman

We present a case of folate deficiency with pancytopenia. Folate deficiency is a known complication of pregnancy. Although pancytopenia is a known consequence of folate deficiency, we would like to emphasize the clinical significance of this life threatening complication in pregnancy

Investigación de la deficiencia de hierro en pacientes con insuficiencia renal crónica en hemodiálisis / Investigation of iron deficiency in patients with chronic kidney failure in hemodialysis

Se estudiaron 19 pacientes con IRC, en hemodiálisis entre 1 y 108 meses. Siete eran mujeres (22-65 años) y 12 varones (22-66 años). La causa de la IRC fue GNC 4, PNC 3, nefroangioesclerosis 3, GNMP 2, uropatía obstructiva 2, indeterminada 2, poliquistosis 1, nefronoptisis 1 y GNPD 1. Nueve pacientes habían recibido transfusiones en el año previo al estudio, pero ninguno había sido tratado con hierro ni con eritropoyetina. La hemocitometría se realizó con un analizador electrónico, también se midió la ferremia, la transferinemia, la ferritina sérica, y el hierro medular en una proporción de los casos. Se observó una correlación significativa entre la ferritina sérica y el hierro medular. La asociación VCM menor de 80 fl y HCM menor de 27 pg tuvo valor predictivo para deficiencia de hierro (ferritina sérica menor de 30 ng/ml y/o hierro medular menor de dos cruces), con 60% de sensibilidad y 100% de especificidad. La ferremia y la saturación de la transferrina no fueron útiles para el diagnóstico de deficiencia de hierro en la IRCHD. Cinco de los 19 pacientes estudiados tenían deficiencia de hierro (26%), y 2 de ellos respondieron favorablemente a la administración parenteral del mismo. El empleo racional de la eritropoyetina recombinante, para el tratamiento de la anemia en la IRCHD, hace necesario investigar la posible deficiencia de hierro así como de otros factores hemopoyéticos en estos pacientes

Serum and red cell folate activity and folic acid absorption in patients with hookworm infection.

Red cell and serum folate levels and folic acid absorption were studied in patients with hookworm infection. The mean value of serum folic acid level was found to be significantly lower than that of the normal subjects and 32% of cases had serum folic acid level less than 4 ng/ml. The red cell folate content in all patients studied were within the normal limits. The mean value of the folic acid absorption was also lower than that of the normal. Six out of 13 patients absorbed folic acid less than 38%, the lowest value obtained from the normal subjects. These findings indicated that there was a negative balance of folic acid in some patients with hookworm infection which was probably due to impairment in absorption.