Nous avons étudié les aspects biochimiques, enzymologiques et génétiques des voies de la méthylation sur les foies foetaux issus d'abortum pour AFTN et témoins. Nous avons mis en évidence un déficit de la vitamine B12 et de la SAM et une baisse des activités MTR et MTHFR dans les tissus AFTN. Ces résultats permettent d'établir qu'une supplémentation en B12 devrait être associée à la supplémentation en folates réalisée en début de grossesse afin de prévenir la survenue de ces AFTN. Nous avons aussi étudié les interactions entre MTR et MMACHC en utilisant des lignées cellulaires de patients porteurs de déficits en MTR (cblG, variant-cblG) et en MMACHC (cblC). Cette étude suggère un rôle régulateur de la MTR dans le métabolisme intracellulaire de la CNCbl, par l'épissage de MTR de deux transcrits codant pour l'enzyme fonctionnelle de taille attendue et une protéine tronquée non fonctionnelle, respectivement / We studied the methylation pathways in liver tissue from fetal NTDs and controls. We identified a vitamin B12 and SAM deficiency and also decreased activities of MTR and MTHFR in NTDs tissue. These results provide evidence that vitamin B12 supplementation should be associated with folate supplementation in early pregnancy in order to prevent the occurrence of these NTDs. We also studied the interactions of MTR with MMACHC by using cell lines patients with MTR and MMACHC deficiency. This study suggests a regulatory role of MTR in the intracellular CNCbl metabolism by splicing of two MTR transcripts encoding the functional enzyme of the expected size and a truncated non-functional protein, respectively

Clinical diagnosis of vitamin B12/cobalt (Co) deficiency is difficult due to the unspecific nature of the clinical symptoms. The apparent increase in vitamin B12 deficiency in New Zealand in the late 1990’s made it clear that health providers were very reliant on plasma reference ranges to diagnose deficiency. However, the lack of quantitative data of what these reference ranges represent in terms of supply of vitamin B12, has prevented a better understanding of the metabolism of vitamin B12 within sheep. This thesis describes the development of an experimental approach to measure vitamin B12 production and absorption in sheep. The model was then used to investigate whether the type of carbohydrate source affects vitamin B12 production and/or absorption. In the first trial (Chapter 4), an adaptation of the repletion technique of Suttle (1974) for copper was used. Previously vitamin B12 depleted sheep were maintained on a diet of 400 g DM meadow hay and 250 g DM crushed barley and which provided a daily intake of 0.03 mg Co. Sheep were intravenously infused with known quantities of vitamin B12 (0 – 200 nmol hydroxycobalamin/d) to determine whether a relationship exists between plasma vitamin B12 concentration and rate of entry of the vitamin into the bloodstream and to quantify the relationship. Eight ewes fitted with rumen and abomasal cannulae were used in a paired 4x4 Latin square design. Four levels of vitamin B12 were infused into the jugular vein for 4 d followed by recovery period of 17 d and the plasma responses measured during this period. Control animals maintained relatively stable plasma levels while levels in treated animals rose sharply within 4 h after the start of infusion. The responses were proportional to infusion rate with a highly significant difference in concentrations observed between treatments (P<0.001). Appearance of vitamin B12 in the plasma was quantified by the relationship Y(pmol/l) = 238 + 102x0.74 where x = infusion rate(nmol B12/d), R² = 0.945. Plasma levels declined rapidly on cessation of infusion and had returned to original pre-treatment levels by the end of the recovery period. The second trial (Chapter 5) quantified plasma responses in relation to dietary Co supply to the rumen. The same eight rumen and abomasal cannulated ewes were used in a paired 4x4 Latin square with 4 levels of intra-ruminal Co infusion in amounts ranging from 0 – 1 mg Co/d as CoSO₄, infused for 4 d followed by a 19 d recovery period. Plasma vitamin B12 response was measured as were concentration of vitamin B12 in abomasal digesta supernatant and digesta liquid flow, the latter using polyethylene glycol as liquid phase marker. Plasma concentration increased from approximately 300 pmol/l to 750 – 800 pmol/l, peaking at day 5 after commencement of infusions. Control animals infused with water maintained base-line plasma vitamin B12 levels around 250 pmol/l. Digesta liquid flow was estimated at 14.6 l/d. The results from Chapters 4 and 5 allowed estimates of vitamin B12 production and absorption. These results are discussed and efficiency of capture of Co into vitamin B12 from dietary Co intake was estimated to decrease from 8.4% to 0.74% as Co intake increased from 0.03 to 1.11 mg Co/d. Absorption coefficient was estimated from the relationships between abomasal vitamin B12 flow and plasma response. The absorption coefficient was calculated to increase from 7 to 10% as abomasal vitamin B12 flow increased from 108 to 142 nmol/d. The current animal model was subsequently used in the final trial (Chapter 6) to investigate whether the type of carbohydrate supplied in the diet influences vitamin B12 production and absorption. The same eight ewes fitted with rumen and abomasal cannulae were used in a 2x4 cross-over design. Half of the ewes were maintained on the basal diet and crushed barley while, for the remainder, the barley was replaced by 250 g of fructose:sucrose in a 80:20 mix during a 7 d period of adaptation. While on their respective diets, both groups were then infused with 0.3 mg Co/d for 6 d, a level chosen to optimise plasma vitamin B12 response. All ewes were then returned to the basal diet and barley for a 15 d recovery period after which treatments were reversed and the procedure repeated. Rumen pH, valeric, propionic, butyric, succinic, and acetic acid and ammonia concentrations were not significantly affected by diet. Digesta flow was 30% greater on a diet enriched with starch compared to sugar-enriched diet. There was an observed difference in vitamin B12 production. However there was no significant diet x time effect on plasma vitamin B12 concentration so any difference in production was negated by a difference in absorption. Carbohydrate supplied as water soluble carbohydrate or starch does not appear to influence plasma vitamin B12 concentration.

This study characterizes B vitamin supplement use prior to and during pregnancy, changes in dietary one-carbon nutrient intakes (folate, vitamin B12, vitamin B6, choline, betaine and methionine) and most significant dietary sources. In Canadian women (Toronto, Ontario) supplemental (n=364) and dietary intakes (using a food frequency questionnaire) (n=290) were assessed during early and late pregnancy. Majority reported using a B vitamin-containing supplement prior (60%) to and during early (93%) and late (89%) pregnancy. Median supplemental intakes of folic acid, B12 and B6 were 1000 µg/d, 2.6 µg/d and 1.9 mg/d, respectively. Dietary one-carbon nutrient intakes did not change appreciably between early and late pregnancy. Most significant sources of folate and B6 were fruits and vegetables, of folic acid were cereals and grains and of B12 were dairy and egg products. Overall, this study provides novel information about one-carbon nutrient intakes in pregnancy which are crucial in maternal and child health.

This study characterizes B vitamin supplement use prior to and during pregnancy, changes in dietary one-carbon nutrient intakes (folate, vitamin B12, vitamin B6, choline, betaine and methionine) and most significant dietary sources. In Canadian women (Toronto, Ontario) supplemental (n=364) and dietary intakes (using a food frequency questionnaire) (n=290) were assessed during early and late pregnancy. Majority reported using a B vitamin-containing supplement prior (60%) to and during early (93%) and late (89%) pregnancy. Median supplemental intakes of folic acid, B12 and B6 were 1000 µg/d, 2.6 µg/d and 1.9 mg/d, respectively. Dietary one-carbon nutrient intakes did not change appreciably between early and late pregnancy. Most significant sources of folate and B6 were fruits and vegetables, of folic acid were cereals and grains and of B12 were dairy and egg products. Overall, this study provides novel information about one-carbon nutrient intakes in pregnancy which are crucial in maternal and child health.

Elevated plasma total homocysteine (ptHcy) or hyperhomocysteinemia (hHcy) independently predicts cardiovascular disease in predialysis chronic kidney disease (pCKD). Folate status is one of the known nutritional determinants of ptHcy. In the era of folic acid food fortification, this cross-sectional study aimed to describe in pCKD subjects (n=48): 1) Prevalence of hHcy. 2) Intake and status of nutrients involved in homocysteine metabolism. 3) Determinants of ptHcy. The prevalence of hHcy was 93.8% (95% CI: 81.8 to 98.4). Median (25th, 75th percentile) total folate intake from food and supplements was 389 (282,640) µg DFE/d. No subject was folate deficient (red blood cell < 317 nmol/L). Red blood cell folate (r = - 0.406, p=0.004) and energy-protein undernutrition (r = 0.357, p=0.013) independently predicted ptHcy. To conclude, total folate intake among subjects with pCKD was sufficient to prevent folate deficiency but not able to prevent a high prevalence of hHcy.

Elevated plasma total homocysteine (ptHcy) or hyperhomocysteinemia (hHcy) independently predicts cardiovascular disease in predialysis chronic kidney disease (pCKD). Folate status is one of the known nutritional determinants of ptHcy. In the era of folic acid food fortification, this cross-sectional study aimed to describe in pCKD subjects (n=48): 1) Prevalence of hHcy. 2) Intake and status of nutrients involved in homocysteine metabolism. 3) Determinants of ptHcy. The prevalence of hHcy was 93.8% (95% CI: 81.8 to 98.4). Median (25th, 75th percentile) total folate intake from food and supplements was 389 (282,640) µg DFE/d. No subject was folate deficient (red blood cell < 317 nmol/L). Red blood cell folate (r = - 0.406, p=0.004) and energy-protein undernutrition (r = 0.357, p=0.013) independently predicted ptHcy. To conclude, total folate intake among subjects with pCKD was sufficient to prevent folate deficiency but not able to prevent a high prevalence of hHcy.

La chlordécone (cld) de formule brute c10cl10o est un pesticide organochloré classé parmi les polluants organiques persistants (pop) par la convention de stockholm en 2009. Ce composé a été appliqué dans les soles bananières des antilles françaisede 1950 à 1993 : ce qui a conduit à une pollution généralisée de l’environnement dans les zones de production de banane. De plus il a été montré une imprégnation généralisée de la biosphère, avec un impact sanitaire décrit dans de nombreuses publications. Il est connu que la cld a une longue persistance dans les sols, conduisant à une contamination des eaux. Aussi, dans les zones polluées de la guadeloupe et de la martinique, les usines de production d'eau ont été équipées de filtres à charbon actif (ca). Cependant, après le traitement, le ca est contaminé, il est alors nécessaire de le régénérer.Un des axes de recherche de l’équipe covachim-m2e « connaissance et valorisation-chimie des matériaux environnement, énergie» est la fabrication de ca préparés à partir des ressources naturelles tropicales telle que la bagasse pour à la fois valoriser des quantités élevées de résidus lignocellulosiques disponibles localement, à un coût modéré, mais surtout pour une adsorption efficace de la cld, afin d’obtenir les informations par le mécanisme d’adsorption de la vb12 sur le ca. Un matériau hybride (mh) composé de ca de la vitamine b12 ou cobalamine (vb12) a été préparé à l’aide d’une fixation non-covalente, par adsorption de manière à préserver l’activité de déchloruration de la vb12.Il est montré que la vb12 réduite par le zinc zérovalent, est capable de dégrader cld, en accord avec les travaux de schrauzer publiés en 1978, montrant que la vb12, réduite par l’acétoine ou bien le borohydrure de sodium était capable dégrader la cld. Les intermédiaires de dégradation produits, ont été caractérisés par chromatographie en phase gazeuse couplée à un spectromètre de masse (cg-sm). Les cinétiques et isothermes d'adsorption de la vb12 sur ca ont été modélisées à l’aide de différents modèles mathématiques ceci permet de comprendre les interactions physico-chimiques mis en jeu entre les deux composants du matériau hybride lors du processus d’adsorption. Il a été révélé que la dynamique d’adsorption est bien décrite par le modèle du pseudo-second ordre. La fixation de la vb12 est plus importante sur le ca bagp1.5, préparé par activation de la bagasse par l’acide phosphorique, avec une valeur capacité d'adsorption maximale déduite du modèle de langmuir de 422 mg.g-1. L’adsorption est favorisée à haute température, et optimale à un ph de 6. En outre, afin d'étudier la stabilité du matériau hybride élaboré, la désorption de la vb12 adsorbée sur la bagp1.5 a également été suivie en milieu aqueux et dans l’éthanol. Le mh ainsi préparé a été caractérisé en utilisant différentes techniques, la méthode de boehm, la microscopie à balayage, la résonance raman, la spectrométrie de fluorescence x, la spectroscopie de photo-électron x, l’infra-rouge à transformée de fourieret aussi par adsorption d’azote.L’objectif de ce travail est d’optimiser la quantification de la cld et de ses intermédiaires de dégradation par une méthode en cg-sm et de mettre au point une méthode de dégradation de la cld en vue de la régénération des ca.Nos travaux ont montré que la vitesse de disparition de la cld est plus élevée pour le matériau hybride, que pour le charbon seul ou la vb12 seule. Les réactions de dégradation de la cld par la vb12 ont montré dans des conditions anaérobies, l’apparition de 3 intermédiaires dérivés de la cld. Ces intermédiaires ont été caractérisés en cg-ms à savoir la mono et dihydrochlordécone, ainsi qu’un dérivé pentachloroindène. / Chlordecone (cld) with an empirical formula c10cl10o is an organochlorine pesticide classified among the persistent organic pollutants (pops) by the stockholm convention in 2009. This compound was applied to banana plantation in the french west indies from 1950 to 1993: resulting to widespread environmental pollution in banana production areas. In addition it has been shown a generalized pollution of the biosphere, with a health impact described in many publications. It is known that cld has a long persistence in soils, leading to water contamination. Consequently, in the polluted areas of guadeloupe and martinique, the water production plants were equipped with activated carbon filters (ac). However, after water treatment, the ac is contaminated, it is then necessary to regenerate it.One of the research areas of the covachim-m2e team is the elaboration of ac from tropical natural resources such as bagasse to both add value the high amounts of lignocellulosic residues locally available at moderate cost, but as well especially for efficient adsorption of the cld. A hybrid material composed of activated carbon (ac) and vitamin b12 (vb12), known as cobalamin was prepared using a non-covalent attachment, by adsorption to preserve the dechlorination activity of vb12.It is shown that vitamin b12 reduced zerovalent zinc is able to degrade cld, in agreement with the work of schrauzer published in 1978, showing that vitamin b12, reduced by acetoin or sodium borohydride capable of degrading the cld. The intermediate degradation products, were characterized by gas chromatography coupled with mass spectrometric detection (gc-ms) to get right one vb12 adsorption mechanism. To get insight on vb12 adsorption mechanism, kinetic and adsorption isotherms of vb12 on ac were modeled using various mathematical models. It allows to understand the physical and chemical interactions involved between the two components of the hybrid material during the adsorption process. It was revealed that the adsorption dynamics is well described by the model of the pseudo-second order and brouers-sotolongo. Amount of the vb12 fixed on is more important on the bagp1.5 ac prepared by activation of the bagasse by the phosphoric acid, as a maximum adsorption capacity value derived from the langmuir model 422 mg.g-1. Adsorption is favored at high temperature, and at optimum value of ph 6. Furthermore, in order to study the stability of the prepared hybrid material, desorption of the adsorbed from bagp1.5 has also been followed in an aqueous medium and in absolute ethanol. Mh thus prepared was characterized using different technique, the method of boehm, scanning electron microscopy, raman resonance, and x-ray fluorescence spectrometry and x-ray photoelectron, infrared transform fourier spectroscopies and also by nitrogen adsorption.The objective of this work is to optimize the quantification of the cld and its intermeodiates by a gas chromatography method coupled with a mass spectrometer (gc-ms) and to develop a method of degradation of the cld for the regeneration of activated carbon.Our work has shown that the rate of disappearance of cld is higher for the hybrid material than vb12 alone. The degradation reactions of cld by vb12 under anaerobic conditions showed the appearance of 3 cld intermediates: mono and dihydrochlordecone and a pentachloroindène derivative that were characterized by gc-ms.

A transcobalamina II (TCII) é a única proteína que leva a cobalamina (Cbl) para dentro das células. A TCII ligada a Cbl é denominada Holo-TC. Polimorfismos no gene TC2 podem alterar tanto a função como a concentração de Holo-TC. Os objetivos deste estudo foram avaliar se o parâmetro Holo-TC é um bom marcador de deficiência de Cbl; avaliar o efeito dos polimorfismos TC2 P259R, I23V e Q234R nos marcadores da deficiência da Cbl; verificar os fatores de predição para os valores de tHcy, SAM/SAH, MMA e Holo-TC nas gestantes e seus recém- nascidos. A Holo-TC não foi bom marcador para discriminar as gestantes com e sem deficiência de Cbl, diferente do encontrado no grupo de recém nascidos. Os genótipos matemos para os polimorfismos TC2 P259R e I23V não foram associados com as alterações nos valores matemos de tHcy, MMA e Holo-TC. Os neonatos portadores dos genótipos PR+RR apresentaram menores valores da razão SAM/SAH e maiores de MMA. Os neonatos com genótipos 23V+23VV apresentaram menores valores de SAM e maiores valores de tHcy. A combinação dos genótipos IV+VV/PR+RR no grupo de gestantes foi associada a menores valores de SAM. Já os neonatos com a mesma combinação de genótipos apresentaram menores valores de SAM e da razão SAM/SAH. O folato sérico foi o melhor fator de predição para a variação da tHcy materna, e a Cbl para os valores de Holo-TC, e finalmente a creatinina e a Cbl foram os fatores de predição para os valores de MMA. A Cbl e o folato foram os preditores para a tHcy neonatal quando foi utilizado apenas as variáveis independentes maternas no modelo de regressão linear múltipla. No entanto, quando as variáveis independentes foram as neonatais, Cbl, folato sérico e SAM/SAH neonatais foram as selecionadas para explicar os valores de tHcy neonatal. Para os modelos neonatais de MMA, a Cbl materna foi a única selecionada quando o modelo foi feito com variáveis independentes maternas. E noutro modelo da MMA neonatal, a Cbl e o genótipo PR + RR neonatal explicaram a variabilidade do MMA neonatal. Para a razão SAM/SAH neonatal, foram o folato sérico e o genótipo RR maternos as variáveis selecionadas quando só foram colocadas as variáveis independentes maternas no modelo. E finalmente, a tHcy e genótipos PR + RR foram as variáveis neonatais selecionadas no modelo de regressão linear múltipla para a razão SAM/SAH neonatal. Podemos concluir que os genótipos para os polimorfismos TC2 P259R e I23V não estão associados a variabilidade dos valores matemos dos metabólitos, no entanto, no recém nascido esta associação foi evidenciada. / Transcobalamin II (TCII) is the only protein that can take cobalamin (Cbl) into cells. When TCII is bound to the Cbl it is called Holo-TC. Polymorphisms inTC2 gene can alter both the function and the concentration of Holo-TC. The objective of this study was to evaluate whether the parameter Holo-TC is a good Cbl deficiency marker; to evaluate the effect of the polymorphisms TC2 P259R, I23V and Q234R in the Cbl deficiency markers; to verify the prediction factors for the values of tHcy, SAM/S~ MMA and Holo-TC in pregnant women and their neonates. Holo-TC has proved not be a good marker for discriminating pregnant women with Cbl deficiency from those without Cbl deficiency, unlike what was seen in the neonatal group. Maternal genotypes for polymorphisms TC2 P259R and I23 V were not related with the alterations ofmaternal values of tHcy, MMA and Holo-TC. The neonates presenting genotypes PR+RR showed lower SAM/SAH ratio values and higher MMA values. The neonates with genotypes 23V+23VV presented lower SAM values and higher tHcy values. The combination of genotypes IV+VV/PR+RR in the group of pregnant women was related with lower SAM values. On the other hand, the neonates presenting the same combination of genotypes presented lower SAM values and SAM/SAH ratio values. Se rum folate was the best predictor for the variation of the maternal tHcy, and Cbl for the Holo-TC values. The creatinine and the Cbl were the predictors for the values of MMA. Cbl and folate were the predictors for the neonatal tHcy when only the maternal independent variables were used in the multiple linear regression model. However, when the neonatal independent variables were used, Cbl, serum folate and SAM/SAH of neonates were selected to explain the neonatal tHcy values. For the neonatal models of MMA, only the maternal Cbl was selected for the model with maternal independent variables. In another neonatal MMA model, Cbl and neonatal PR + RR genotype explained the variability of the neonatal MMA. For the neonatal SAM/SAH ratio, serum folate and maternal RR genotype were the variables selected when only the maternal independent variables were used in the model. Finally, tHcy and genotypes PR + RR were the neonatal variables selected in the multiple linear regression model for the neonatal SAM/SAH ratio. We have concluded that the genotypes for the polymorphisms TC2 P25 9R and I23 V are not related to the variability of the maternal values of the metabolites; however, this relation is clear when evaluating the values observed in their newborn babies.

Objetivo Examinar a correlação entre fatores dietéticos, obtidos por questionário de freqüência alimentar (QFA) validado, e concentrações séricas ou plasmáticas de homocisteína (hcy), ácido fólico, vitaminas B12 e B6 em mulheres de São Paulo. População e métodos Foram analisados os dados dietéticos de 1.434 mulheres de 21 a 65 anos de um estudo caso-controle sobre consumo alimentar e lesões neoplásicas do colo uterino realizado em três hospitais públicos da cidade de São Paulo, excluindo-se os casos de câncer invasivo. Todas participantes tiveram sua ingestão alimentar usual avaliada por entrevista, usando um QFA, e forneceram amostras sangüíneas em jejum para separação de plasma e soro. Concentrações séricas de ácido fólico e vitamina B12 séricos foram analisadas por técnica de fluoroimunoensaio, enquanto concentrações plasmáticas de hcy e vitamina B6 foram analisadas por Cromatografia Líquida de Alta Performance em fase reversa. Correlações entre ingestão estimada de nutrientes, ajustados pelas calorias totais, e alimentos com as variáveis bioquímicas foram avaliadas em modelos de regressão linear múltiplos, após ajuste para co-variáveis, tais como idade, Índice de Massa Corporal (IMC), estilo de vida (incluindo tabagismo), morbidade ginecológica pregressa ou atual, história obstétrica e uso de anticoncepcional oral. Resultados Embora apenas 6,2% das participantes do estudo tenham apresentado concentrações séricas de ácido fólico abaixo do valor de referência (7 nmol/L), 45,7% e em 97,1% tiveram um consumo estimado de folato inferior a 180 ug/dia e 400 ug/dia, respectivamente. Modelos de regressão múltiplos mostraram correlação positiva entre ácido fólico sérico e ingestão estimada de proteína, ferro, folato, vitaminas B1, B3, B6, A, C e frutas/sucos cítricos e de vegetais verdes, e correlação inversa entre ácido fólico sérico e consumo estimado de gorduras, doces e leite e derivados. Resultados similares foram obtidos após ajuste adicional para fibra da dieta, exceto com consumo de folato e de vegetais verdes, que perderam a significância estatística como preditores independentes das concentrações séricas de ácido fólico. Concentrações séricas de vitamina B12 abaixo do ponto de corte de 148 pmol/L foram observadas em 11,0% da amostra; a maioria delas (70,4%) apresentou ingestão estimada de vitamina B12 igual ou superior à recomendação (2 ug/dia). As concentrações séricas de vitamina B12 foram positivamente correlacionadas com consumo estimado de produtos lácteos e das vitaminas B2 e B12. A ingestão de fibra, vitamina E e leguminosas foi inversamente correlacionada com as concentrações séricas de vitamina B12. Ingestão de vitamina B6 abaixo das recomendações de 1,3 mg/dia (&#8804;50 anos) e 1,5 mg/dia (>50 anos) foi observada em 49% das participantes. Nenhuma correlação foi encontrada entre dados da dieta e concentrações plasmáticas de vitamina B6. As concentrações plasmáticas de hcy foram positivamente correlacionadas com o consumo estimado de carboidratos e doces, e inversamente correlacionadas com o consumo estimado de proteína, colesterol, ferro, zinco de origem animal, vitaminas A, B2, B12 e B6, e pescados. Entretanto, essas correlações perderam a significância após ajuste adicional por proteína da dieta, um dos mais fortes preditores das concentrações plasmáticas de hcy. Conclusão Nutrientes e alimentos selecionados da dieta mostraram-se preditores independentes das concentrações séricas de ácido fólico e de vitamina B12, indicando as principais fontes alimentares desses nutrientes nesta população e em outras similares. A forte correlação negativa entre concentração plasmática de Hcy e proteína da dieta sugere base para o planejamento de futuras intervenções nutricionais. Nenhuma correlação foi observada entre concentração plasmática de vitamina B6 e fatores dietéticos estimados. / Objective To examine whether measurements of dietary intakes, obtained with a validated quantitative food frequency questionnaire (FFQ), correlated with serum or plasma levels of folic acid, vitamins B12 and B6 and homocystein (hcy) measured in low-income women living in São Paulo, Brazil. Population and methods We analyzed dietary data from 1434 women aged 21-65 years enrolled in a case-control study of diet and cervical cancer carried out in three public hospitals of São Paulo. Data for women with invasive cervical cancer were excluded. All participants had their usual dietary intake assessed by interview, using a validated FFQ, and provided a fasting blood sample for serum and plasma separation. Serum concentrations of folic acid and vitamin B12 were measured by fluorimmunoassay, while serum levels of vitamin B6 and plasma levels of hcy were measured by reversed-phase high performance liquid chromatography. Correlations between estimates of food and energy-adjusted nutrient intakes and levels of folic acid, vitamins B12 and B6 and hcy were assessed using multiple linear regression models, adjusted for covariates such as age, body mass index, lifestyle (including smoking), past and current gynecologic morbidity and obstetric history, and use of oral contraceptives. Results Although only 6.2% of the study participants had serum folic acid levels below the reference value of 7 nmol/L, 45.7% and 97.1% had a dietary intake of folic acid estimated to be less than 180 &#61549;g/day and 400 &#61549;g/day, respectively. Multiple linear models showed serum folic acid levels to be positively correlated with the estimated intake of protein, iron, folate, vitamins B1, B3, B6, A and C, citrus fruits and juices and green vegetables, and negatively correlated with the estimated intake of fat, sweets and dairy products. Similar results were obtained after a further adjustment for fiber intake in the model, except for the estimated intake of folic acid and green vegetables, which lost their statistical significance as independent predictors of serum folic acid levels. Serum levels of vitamin B12 below the cut-off point of 148 pmol/L were found in 11.0% of study participants; most of them (70.4%) had their vitamin B12 intake estimated to be equal or greater than the reference value of 2 &#61549;g/day. Serum levels of vitamin B12 were positively correlated with the estimated intake of dairy products and vitamins B2 and B12. The estimated intakes of fiber, vitamin E and beans were negatively correlated with serum levels of vitamin B12. Dietary vitamin B6 was estimated to be below the recommended levels of 1.3 mg/day (age &#61603; 50 years) or 1.5 mg/day (age > 50 years) in 49.0% of study participants. No correlation was found between estimated intakes of foods and nutrients and plasma levels of vitamin B6. Hcy concentrations were positively correlated with the estimated intake of carbohydrates and sweets, and negatively correlated with the estimated intake of protein, cholesterol, iron, zinc of animal origin, vitamins A, B2, B12 and B6 and fishes. However, these correlations were no longer significant after additional adjustment for dietary protein, the strongest predictor of hcy plasma levels. Conclusion The estimated dietary intakes of selected foods and nutrients were shown to be independent predictors of measured serum levels of folic acid and vitamin B12, providing a basis for indentifying the main dietary sources of these nutrients in this and similar populations. The strong negative correlation between plasma levels of hcy and dietary protein provides a basis for future nutritional interventions. No correlation was found between plasma concentrations of vitamin B6 and estimated dietary intakes.

This study aims to analyze the effect of an improvised user-generated health awareness campaign which was based on a personal narrative and first-hand experience with the B12 deficiency symptoms in babies and toddlers. The campaign was conducted in 2015 with a follow-up video in 2016 and shared through social media outlets, informing about the topic and empowering individuals to take responsibility for their own or their child’s health by providing information that could serve as a guideline for early diagnosis and intervention and by presenting an outlook of how people with similar issues manage the condition.The impact of the campaign is being qualitatively and quantitatively accessed by interviews with medical professionals and respectively survey data from a national survey and statistics from the YouTube console. In consideration has been taken the trust the respondents have in the medical service and the usual access to health information both online and offline The quantitative data were collected using a national online survey in which 1185 individuals took part. It aimed to additionally identify the general public attitude towards medical service in and the awareness about the vitamin B12. Four people participated in the interviews, divided into two groups - parents of children, who had symptoms similar to those, shown in the videos; and health practitioners who have seen the videos and comment on its qualities as a self-diagnosing material as well as the effect that attention to the issue created on their medical practices. The results confirmed that the personal narrative of a campaign could help to create identification and thus be more persuasive and with further increased sharing potential of the message through social media. The concrete campaign reached cumulatively over 167.000 people through YouTube, which is around 2.4% of the population of Bulgaria and possibly creating a lasting impact on the public attitude towards vitamin/mineral and other deficiencies. We found out that social media and YouTube could serve as an impactful medium for disseminating health-related information online when accurate and persuasive information is being used. When addressing a wide audience with little or no prior knowledge of the subject the personal narrative or testimonial could create more impact than a neutral fact-providing material.