[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. Poor folate 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

Comparison of two modes of vitamin B12 supplementation on neuroconduction and cognitive function among older people living in Santiago, Chile: a cluster randomized controlled trial. a study protocol [ISRCTN 02694183]

BACKGROUND: Older people have a high risk of vitamin B12 deficiency; this can lead to varying degrees of cognitive and neurological impairment. CBL deficiency may present as macrocytic anemia, subacute combined degeneration of the spinal cord, or as neuropathy, but is often asymptomatic in older people. Less is known about subclinical vitamin B12 deficiency and concurrent neuroconduction and cognitive impairment. A Programme of Complementary Feeding for the Older Population (PACAM) in Chile delivers 2 complementary fortified foods that provide approximately 1.4 μg/day of vitamin B12 (2.4 μg/day elderly RDA). The aim of the present study is to assess whether supplementation with vitamin B12 will improve neuroconduction and cognitive function in older people who have biochemical evidence of vitamin B12 insufficiency in the absence of clinical deficiency. METHODS: We designed a cluster double-blind placebo-controlled trial involving community dwelling people aged 70-79 living in Santiago, Chile. We randomized 15 clusters (health centers) involving 300 people (20 per cluster). Each cluster will be randomly assigned to one of three arms: a) a 1 mg vitamin B12 pill taken daily and a routine PACAM food; b) a placebo pill and the milk-PACAM food fortified to provide 1 mg of vitamin B12; c) the routine PACAM food and a placebo pill.The study has been designed as an 18 month follow up period. The primary outcomes assessed at baseline, 4, 9 and 18 months will be: serum levels of vitamin B12, neuroconduction and cognitive function. CONCLUSIONS: In view of the high prevalence of vitamin B12 deficiency in later life, the present study has potential public health interest because since it will measure the impact of the existing program of complementary feeding as compared to two options that provide higher vitamin B12 intakes that might potentially may contribute in preserving neurophysiologic and cognitive function and thus improve quality of life for older people in Chile. TRIAL REGISTRATION: ISRCTN: ISRCTN02694183

Salud de los trabajadores

Actividad física y su relación con los factores de riesgo cardiovascular de carteros chilenosAnálisis de resultados: riesgos psicosociales en el trabajo Suceso-Istas 21 en Cesfam QuellónAusentismo laboral por enfermedades oftalmológicas, Chile 2009Brote de diarreas por norovirus, posterremoto-tsunami, Constitución, Región del MauleCalidad de vida en profesionales de la salud pública chilenaCaracterización del reposo laboral en personal del SSMN durante el primer semestre de 2010Concentración de nicotina en pelo en trabajadores no fumadores expuestos a humo de tabaco ambientalCondiciones de trabajo y bienestar/malestar docente en profesores de enseñanza media de SantiagoDisfunción auditiva inducida por exposición a xilenoErgonomía aplicada al estudio del síndrome de dolor lumbar en el trabajoEstimación de la frecuencia de factores de riesgo cardiovascular en trabajadores de una empresa mineraExposición a plaguicidas inhibidores de la acetilcolinesterasa en Colombia, 2006-2009Factores de riesgo y daños de salud en conductores de una empresa peruana de transporte terrestre, 2009Las consecuencias de la cultura en salud y seguridad ocupacional en una empresa mineraPercepción de cambios en la práctica médica y estrategias de afrontamientoPercepción de la calidad de vida en la Universidad del BiobíoPesos máximos aceptables para tareas de levantamiento manual de carga en población laboral femeninaRiesgo coronario en trabajadores mineros según la función de Framingham adaptada para la población chilenaTrastornos emocionales y riesgo cardiovascular en trabajadores de la salu

Variación estacional del perfil lipídico en adultos aparentemente sanos de Santiago, Chile

El perfil lipídico depende de muchos factores. Sin embargo, las variaciones estacionales de estos componentes han sido escasamente establecidas en el hemisferio sur. El objetivo de este estudio fue determinar la variación estacional del perfil lipídico por un periodo de un año en un grupo de adultos aparentemente sanos de Santiago, Chile. El diseño del estudio fue observacional y prospectivo. Participaron en el estudio 50 voluntarios sanos de ambos sexos y de edades entre 23 a 62 años. En forma mensual y durante un año se midió el perfil lipídico. LDL fue significativamente mayor en invierno y primavera que en verano (p<0,01). Por el contrario HDL disminuye en invierno (p<0,05). Se concluye que existen variaciones estacionales en los niveles séricos de LDL y HDL. El patrón circanual está caracterizado por mayores niveles de LDL en invierno y primavera y menores niveles de HDL en invierno.The lipid profile is impacted by numerous factors. However, the seasonal variations in this profile have not been well-established in the southern hemisphere. The aim of this study was to determine the seasonal variation of the lipid profile in apparently healthy adults from Santiago, Chile. The study design was observational and prospective, involving 50 healthy volunteers of both genders, aged 23-62 years. The lipid profile was measured at monthly intervals over the course of one year. LDL was significantly higher in winter -spring than in summer- fall (p <0.01). Conversely, HDL decreases significantly in winter (p<0,05). We conclude that there are seasonal variations in the serum levels of LDL and HDL. The circannual pattern is characterized by increased levels of LDL in winter-spring and low levels of HDL in winter

Variación estacional del perfil lipídico en adultos aparentemente sanos de Santiago, Chile

El perfil lipídico depende de muchos factores. Sin embargo, las variaciones estacionales de estos componentes han sido escasamente establecidas en el hemisferio sur. El objetivo de este estudio fue determinar la variación estacional del perfil lipídico por un periodo de un año en un grupo de adultos aparentemente sanos de Santiago, Chile. El diseño del estudio fue observacional y prospectivo. Participaron en el estudio 50 voluntarios sanos de ambos sexos y de edades entre 23 a 62 años. En forma mensual y durante un año se midió el perfil lipídico. LDL fue significativamente mayor en invierno y primavera que en verano (p<0,01). Por el contrario HDL disminuye en invierno (p<0,05). Se concluye que existen variaciones estacionales en los niveles séricos de LDL y HDL. El patrón circanual está caracterizado por mayores niveles de LDL en invierno y primavera y menores niveles de HDL en invierno.The lipid profile is impacted by numerous factors. However, the seasonal variations in this profile have not been well-established in the southern hemisphere. The aim of this study was to determine the seasonal variation of the lipid profile in apparently healthy adults from Santiago, Chile. The study design was observational and prospective, involving 50 healthy volunteers of both genders, aged 23-62 years. The lipid profile was measured at monthly intervals over the course of one year. LDL was significantly higher in winter -spring than in summer- fall (p <0.01). Conversely, HDL decreases significantly in winter (p<0,05). We conclude that there are seasonal variations in the serum levels of LDL and HDL. The circannual pattern is characterized by increased levels of LDL in winter-spring and low levels of HDL in winter

Non-heme iron as ferrous sulfate does not interact with heme iron absorption in humans

The absorption of heme iron has been described as distinctly different from that of non-heme iron. Moreover, whether heme and non-heme iron compete for absorption has not been well established. Our objective was to investigate the potential competition between heme and non-heme iron as ferrous sulfate for absorption, when both iron forms are ingested on an empty stomach. Twenty-six healthy nonpregnant women were selected to participate in two iron absorption studies using iron radioactive tracers. We obtained the dose-response curve for absorption of 0.5, 10, 20, and 50 mg heme iron doses, as concentrated red blood cells. Then, we evaluated the absorption of the same doses, but additionally we added non-heme iron, as ferrous sulfate, at constant heme/non-heme iron molar ratio (1:1). Finally, we compare the two curves by a two-way ANOVA. Iron sources were administered on an empty stomach. One factor analysis showed that heme iron absorption was diminished just by increasing total heme

Low prevalence of iron deficiency anemia between 1981 and 2010 in Chilean women of childbearing age.

Objective. To determine the prevalence of anemia and iron status among Chilean women of childbearing age between 1981 and 2010. Materials and methods. Calculation of the prevalence of anemia and iron status was based on multiple cross-sectional iron absorption studies performed in 888 women during this period of time. All studies included measurements of hemoglobin, mean corpuscular volume, zinc protoporphyrin, percentage of transferrin saturation and serum ferritin. Data were grouped by decade (1981-1990,1991-2000, and 2001-2010). Results. Prevalence of anemia for these decades was 9, 6 and 10%, respectively (p=NS). Iron deficiency anemia was the main cause of anemia in all periods (55, 85 and 75%, respectively; p=NS). A high prevalence of women with normal iron status was observed for all periods (64, 69, and 67, respectively; p=NS). Prevalence of iron deficiency without anemia in 1981-1990, 1991-2000 and 2001-2010 was 7, 20 and 12%, respectively (p menor que 0.05). Finally, prevalence of iron depleted stores was 20, 6 and 10%, respectively (p menor que 0.05). Conclusions. Prevalence of iron deficiency anemia in Chilean women of childbearing age was mild between 1981 and 2010. More than 60% of childbearing age women presented normal iron status in all periods. However, prevalence of iron depleted stores was moderate during 1981-1990, and was mild during 1991-2000 and 2001-2010

The Effect of Plant Proteins Derived from Cereals and Legumes on Heme Iron Absorption

The aim of this study is to determine the effect of proteins from cereals and legumes on heme iron (Fe) absorption. The absorption of heme Fe without its native globin was measured. Thirty adult females participated in two experimental studies (15 per study). Study I focused on the effects of cereal proteins (zein, gliadin and glutelin) and study II on the effects of legume proteins (soy, pea and lentil) on heme Fe absorption. When heme was given alone (as a control), study I and II yielded 6.2% and 11.0% heme absorption (p > 0.05). In study I, heme Fe absorption was 7.2%, 7.5% and 5.9% when zein, gliadin and glutelin were added, respectively. From this, it was concluded that cereal proteins did not affect heme Fe absorption. In study II, heme Fe absorption was 7.3%, 8.1% and 9.1% with the addition of soy, pea and lentil proteins, respectively. Only soy proteins decreased heme Fe absorption (p < 0.05). These results suggest that with the exception of soy proteins, which decreased absorption, proteins derived from cereals and legumes do not affect heme Fe absorption

One-month of calcium supplementation does not affect iron bioavailability: A randomized controlled trial

Artículo de publicación ISIObjectives: Calcium (Ca) and iron (Fe) are essential minerals for normal growth and development. Although previous studies have shown that Ca inhibits acute Fe absorption, there is no evidence of the possible long- or medium-term effects of Ca supplementation on Fe bioavailability. The aim of this study was to determine the effect of 34 d of Ca supplementation on heme Fe and non-heme Fe bioavailability in non-pregnant women of ages 33 to 47 y. Methods: This was a prospective, randomized, double-blind, placebo-controlled trial. Twenty-six healthy women (40 5 y) were randomly assigned to receive either 600 mg of elemental Ca/d as CaCO3 (Ca group, n ¼ 13) or a placebo (P group, n ¼ 13) for 34 d. Heme Fe and non-heme Fe bioavailability were determined before and after treatment using 55Fe and 59Fe radioisotopes. A two-factor, repeated-measures analysis of variance was used to assess differences by treatment and timing. Results: The geometric mean (range 1 SD) of heme Fe bioavailability before and after treatment was 16.5% (8.3–32.8) and 26% (15.5–43.6) for the Ca group and 21.8% (13.0–36.6) and 25.1% (16.5–38.3) for the P group. Non-heme Fe bioavailability before and after treatment was 39.5% (19.9–78.7) and 34.1% (19.1–60.6) for the Ca group, and 44.6% (24.9–79.7) and 39.3% (24.3–63.4) for the P group. There were no differences in either heme Fe or non-heme Fe bioavailability either at baseline or after treatment. Conclusion: The administration of calcium supplements for 34 d does not affect iron bioavailability. This trial is registered with Controlled-trials.gov, number ISRCTN 89888123.The study was supported by grants from the Chilean National Research Council (FONDECYT 1095038). We would like to thank Sotiris Chaniotakis for his work editing this manuscript

Less than adequate vitamin D status and intake in Latin America and the Caribbean: A problem of unknown magnitude

Artículo de publicación ISIBackground. The prevalence of vitamin D deficiency in Latin America and the Caribbean is unknown. Objective. To examine the prevalence data available on vitamin D deficiency in Latin America and the Caribbean. Methods. A systematic review was conducted in 2011. Studies using biochemical biomarkers and dietary intake estimation were included. Studies conducted in apparently healthy individuals, independently of age, latitude, skin pigmentation, and season of the year at the time of blood collection, were included. Results. A total of 243 studies were identified. The final number of selected studies was 28, including two National Health Surveys (Mexico and Argentina). There are studies that report the vitamin D status of specific subgroups conducted in Argentina, Brazil, Chile, Colombia, Ecuador, Guatemala, and Mexico. However, the small sample sizes in these studies and thus the low national representativeness of the reported data do not allow for an accurate assessment of vitamin D status at the regional level. In the majority of the countries with available data, we observed that vitamin D insufficiency was classified as a mild, moderate, or severe public health problem. The only country with a nationally representative sample was Mexico, which found 24%, 10%, 8%, and 10% prevalence rates of vitamin D insufficiency (25-hydroxyvitamin D < 50 nmol/L) in preschoolers, schoolchildren, adolescents, and adults, respectively. The prevalence of vitamin D deficiency (25-hydroxyvitamin D < 20 nmol/L) was less than 1% for all groups. Conclusions. There is some indication that vitamin D insufficiency may be a public health problem in Latin America and the Caribbean, but the exact magnitude is currently unknown