With the increased marketing and popularity of a range of dairy products in recent years, research has become widespread concerning the influence of dairy on human health. It is also becoming evident that an individual’s genetic make-up contributes to shaping their health responses to dietary intakes. This research was primarily designed to investigate the impact of genetic variability on responsiveness of cholesterol metabolism, a classic biomarker of cardiovascular health, to the recommended level of dairy consumption in Canada. A secondary objective was to assess the influence of dairy intake on systemic inflammation as an emerging risk factor for cardiovascular disease. In a multicentre, randomized, free-living crossover design, 124 healthy individuals consumed 3 servings/day of conventional low-fat and regular milk, yogurt, and cheese (DAIRY diet) or dairy-free control products (CONTROL diet), each for 28 days as part of a prudent background dietary protocol. At the end of the study, DAIRY was associated with increased plasma concentrations of two established fatty acid biomarkers of dairy fat, pentadecanoic acid (C15:0) and heptadecanoic acid (C17:0), as well as with small increases in serum total cholesterol (TC) and LDL-cholesterol (LDL-C) concentrations. Inter-individual variability in the cholesterol transport gene ABCG5, bile acid synthesis gene CYP7A1, and cholesterol synthesis gene DHCR7 contributed to shaping the degree of TC and LDL-C responsiveness to DAIRY; with higher cholesterol concentrations observed among ABCG5 rs6720173-G/G homozygotes, CYP7A1 rs3808607-G allele carriers, and DHCR7 rs760241-A allele carriers, relative to the C allele, T/T, and G/G carriers of these genes, respectively. Also, after DAIRY, the major allele T homozygosity of CYP7A1 rs3808607 and the minor allele A of DHCR7 rs760241 were associated with reduced plasma [3,4]13C cholesterol enrichment and deuterium incorporation, respectively, suggesting reduced cholesterol absorption and synthesis rates. DAIRY intake did not influence the inflammatory status. Overall, this research has provided evidence of a potential impact of the genomic architecture on responsiveness of cholesterol metabolism to dairy consumption. The novel findings are expected to advance knowledge of the inherited basis by which health biomarkers may be modified in response to whole foods, hence launching an important step towards an era of personalized nutrition. / February 2016

Animal studies have shown that chronic high consumption of saturated fat (SF) leads to hypothalamic inflammation and ultimately, alters appetite control. This has been shown to be partly due to an increase in the activity of the transcription factor Nuclear Factor-κB (NF-κB), a major regulator of the inflammatory response. The goal of the study was to first confirm the association between SF measurements and anthropometric traits, then to determine the association between single nucleotide polymorphisms (SNPs) in the NF-κB1 gene and body mass index (BMI) and waist circumference (WC), and finally, to test the interaction between variants in this gene and dietary SF and circulating saturated fatty acids (CSFA) on these anthropometric traits in young adults. A significant positive association was identified between quartiles of CSFA and anthropometric measurements in the total sample (BMI: p = 0.0003, WC: p = 0.0001) and in South Asians (BMI: p = 0.004, WC: p = 0.01), but only marginally among Caucasians (BMI: p = 0.08, WC: p = 0.051) and East Asians (BMI: p = 0.13, WC: p = 0.053). After correcting for false discovery rate, carriers of the T allele in SNP rs4648022 had higher BMI and WC compared to those with the dominant CC genotype (p = 0.0003 and p = 0.0001, respectively). Among Caucasians, there was a significant interaction between SNPs in the NF-κB1 gene and quartiles of CSFA on WC for rs4648095 (p = 0.002). Thus, certain SNPs in the NF-κB1 gene appear to influence BMI and WC and also to modify the association between CSFA and anthropometric traits.

Introdução: A deficiência de ferro é frequente entre mulheres na idade reprodutiva e é considerada problema de saúde pública mundial. Por outro lado, patologias associadas com aumentada atividade eritropoética e sobrecarga de ferro, como as talassemias e a anemia falciforme, estão entre as doenças monogênicas mais frequentes em muitas populações. Os genes HFE e TMPRSS6 codificam as proteínas hemocromatose hereditária (HFE) e matriptase-2 (MT2) que, no fígado, modulam a produção de hepcidina, o hormônio regulador central do metabolismo de ferro. O objetivo deste estudo foi avaliar a relação entre o consumo alimentar de ferro, as variantes rs855791 (MT2736V), rs4820268 (MT2521V), rs1799945 (HFE63D) e rs1800562 (HFE282Y) e o status corporal do mineral entre mulheres com atividade eritropoética normal (aparentemente saudáveis) ou levemente aumentada (com β-talassemia menor). Casuística e métodos: Inicialmente, foram incluídas 127 estudantes universitárias na idade reprodutiva (18 a 42 anos) e em aparente balanço estacionário do ferro corporal (necessidades fisiológicas e consumo alimentar de ferro pouco variáveis há pelo menos 12 meses). Em um segundo estudo, foram incluídos 33 casos de β-talassemia menor (18 na pós-menopausa), registrados em serviços de hematologia de dois hospitais de São Paulo-SP e um de Sorocaba-SP. Essas foram pareadas com 66 controles, segundo idade, índice de massa corporal, status reprodutivo e uso de anticoncepcionais hormonais. A partir de inquéritos feitos com registros alimentares ou recordatórios de 24 horas foi estimado o consumo de ferro total e biodisponível. Amostras de sangue foram utilizadas para a extração de DNA e determinações de ferritina sérica, saturação da transferrina e hemoglobina. As genotipagens do TMPRSS6 e do HFE foram realizadas por PCR em tempo real. Resultados: Considerando as 226 mulheres avaliadas, as frequências dos alelos MT2736V, MT2521D, HFE63D e HFE282Y foram estimadas em 40,3%, 44,0%, 16,3% e 1,5% respectivamente. No primeiro estudo, foi estimada média de consumo de ferro 10 de 10,9 mg/dia e prevalência de deficiência do mineral de 12,6%. Estimativas de consumo de ferro biodisponível, mas não de ferro total, foram correlacionadas com os valores de ferritina e saturação da transferrina. As associações entre a biodisponibilidade dietética de ferro e seus biomarcadores foram especialmente evidentes entre as carreadoras da variante HFE63D, indicando uma significante interação gene-nutriente. Por outro lado, valores relativamente menores de saturação da transferrina foram associados à presença do alelo MT2736V, independentemente do consumo de ferro biodisponível. Mulheres com β-talassemia menor e suas controles não diferiram quanto à frequência das variantes TMPRSS6 e HFE ou à biodisponibilidade dietética de ferro. Na pós-menopausa, a β-talassemia menor foi associada com valores duas vezes maiores de ferritina, 20% maiores de saturação da transferrina e com probabilidade 3,5 vezes maior de hiperferritinemia. Entretanto, para casos e controles na idade reprodutiva, foi estimada probabilidade de inadequação do consumo de 20,7% e prevalências de deficiência do mineral de 13,3% e 10,0%, respectivamente. Entre essas mulheres, o genótipo positivo ou negativo para a variante MT2736V foi também associado com diferenças nas médias de saturação da transferrina. No entanto, o contraste nesses valores foi relativamente maior entre as mulheres com β-talassemia menor. Além disso, mais acentuada hipocromia acompanhou a presença da variante MT2736V nessa condição. Conclusão: Os achados sugerem que, entre mulheres com eritropoese normal ou com β-talassemia menor, a variante MT2736V não afeta tão fortemente as reservas de ferro corporal como faz a adequação do consumo desse mineral. Ainda assim, a variante HFE63D pode modificar a relação da biodisponibilidade de ferro com seu status corporal e, portanto, ser um importante marcador preditivo de resposta diferencial à dieta. A variante MT2736V foi associada com menor disponibilidade de ferro na circulação de mulheres na idade reprodutiva e, entre aquelas com &#946.;-talassemia menor, com indício de acentuada alteração morfológica dos eritrócitos. / Introduction: Iron deficiency is common among women at childbearing age and it is regarded as a worldwide public health issue. On the other hand, disorders associated with increased erythropoietic activity and iron overload, such as thalassemias and sickle cell disease, are among the most frequent Mendelian diseases in many populations. HFE and TMPRSS6 genes encode the hereditary hemochromatosis protein (HFE) and the matriptase-2 (MT2) both of which modulate the hepatic production of hepcidin, the main hormone regulator of iron metabolism. The aim of this study was to evaluate the relationship among dietary iron intake, rs855791 (MT2736V), rs4820268 (MT2521D), rs1799945 (HFE63D) and rs1800562 (HFE282Y) genetic variants and body iron status of women with normal (apparently healthy) or slightly increased (β-thalassemia minor) erythropoietic activity. Casuistic and methods: Initially, 127 university students at childbearing age (18 to 42 years old) and with steady state body iron (few variations on physiological requirements and dietary iron intake at least for the last 12 months) were included. In a second study, it was included 33 cases of β-thalassemia minor (18 of them post-menopaused) registered in Hematology Services from two hospitals from São Paulo-SP and one from Sorocaba-SP. They were paired with 66 controls by age, body mass index, reproductive status and hormonal contraceptive use. Using food diaries or 24 hours food recalls, total and bioavailable dietary iron intakes were estimated. Blood samples were used for DNA extraction and for determinations of ferritin, transferrin saturation with iron and hemoglobin. TMPRSS6 and HFE genotyping were performed by real time PCR. Results: Considering all the 226 women studied, the allelic frequencies of MT2736V, MT2521D, HFE63D e HFE282Y genetic variants were em 40.3%, 44.0%, 16.3% e 1.5%, respectively. In the first study, a total dietary iron intake of 10.9 mg/day and an iron deficiency prevalence of 12.6% were estimated. There were correlations among ferritin and transferrin saturation values with estimates of bioavailable, but not of total dietary iron intake s. Associations between dietary iron bioavailability and iron biomarkers were especially evident among carriers of HFE63D variant, indicating a significant gene-diet interaction. On the other hand, lower levels of transferrin saturation were associated with the presence of MT2736V variant allele, irrespective of bioavailable iron intake. TMPRSS6 and HFE variants frequencies and dietary iron bioavailability estimates did not differ between women with β-thalassemia minor and their controls. Among postmenopausal women, β-thalassemia minor was associated with two times higher ferritin values, 20% higher transferrin saturation values and 3.5 times higher chance for hiperferritinemia. However, among cases and controls at childbearing age, it was estimated a probability of inadequacy in the dietary iron intake of 20.7% and iron deficiency prevalences of 13.3% and 10.0%, respectively. Among these women, a positive or negative genotype for MT2736V was also associated with differences in transferrin saturation. Nevertheless, the contrast between these values was relatively higher among women with β-thalassemia minor. Moreover, a more accentuated hypochromia accompanied the presence of the MT2736V variant in this condition. Conclusions: Our findings suggest that, among women with normal erythropoiesis or β-thalassemia minor, the presence of the MT2736V variant does not strongly impact the body iron stores as does dietary iron adequacy. Nevertheless, the HFE63D variant may modify the relationship between the dietary iron bioavailability and the body iron status. Therefore, it might be an important predictive marker of women\'s differential response to diet. The MT2736V variant was associated with lower availability of circulating iron in women at childbearing age and, among those with β-thalassemia minor, with suggestive accentuated morphological alteration of erythrocytes.

Introdução: A deficiência de ferro é frequente entre mulheres na idade reprodutiva e é considerada problema de saúde pública mundial. Por outro lado, patologias associadas com aumentada atividade eritropoética e sobrecarga de ferro, como as talassemias e a anemia falciforme, estão entre as doenças monogênicas mais frequentes em muitas populações. Os genes HFE e TMPRSS6 codificam as proteínas hemocromatose hereditária (HFE) e matriptase-2 (MT2) que, no fígado, modulam a produção de hepcidina, o hormônio regulador central do metabolismo de ferro. O objetivo deste estudo foi avaliar a relação entre o consumo alimentar de ferro, as variantes rs855791 (MT2736V), rs4820268 (MT2521V), rs1799945 (HFE63D) e rs1800562 (HFE282Y) e o status corporal do mineral entre mulheres com atividade eritropoética normal (aparentemente saudáveis) ou levemente aumentada (com β-talassemia menor). Casuística e métodos: Inicialmente, foram incluídas 127 estudantes universitárias na idade reprodutiva (18 a 42 anos) e em aparente balanço estacionário do ferro corporal (necessidades fisiológicas e consumo alimentar de ferro pouco variáveis há pelo menos 12 meses). Em um segundo estudo, foram incluídos 33 casos de β-talassemia menor (18 na pós-menopausa), registrados em serviços de hematologia de dois hospitais de São Paulo-SP e um de Sorocaba-SP. Essas foram pareadas com 66 controles, segundo idade, índice de massa corporal, status reprodutivo e uso de anticoncepcionais hormonais. A partir de inquéritos feitos com registros alimentares ou recordatórios de 24 horas foi estimado o consumo de ferro total e biodisponível. Amostras de sangue foram utilizadas para a extração de DNA e determinações de ferritina sérica, saturação da transferrina e hemoglobina. As genotipagens do TMPRSS6 e do HFE foram realizadas por PCR em tempo real. Resultados: Considerando as 226 mulheres avaliadas, as frequências dos alelos MT2736V, MT2521D, HFE63D e HFE282Y foram estimadas em 40,3%, 44,0%, 16,3% e 1,5% respectivamente. No primeiro estudo, foi estimada média de consumo de ferro 10 de 10,9 mg/dia e prevalência de deficiência do mineral de 12,6%. Estimativas de consumo de ferro biodisponível, mas não de ferro total, foram correlacionadas com os valores de ferritina e saturação da transferrina. As associações entre a biodisponibilidade dietética de ferro e seus biomarcadores foram especialmente evidentes entre as carreadoras da variante HFE63D, indicando uma significante interação gene-nutriente. Por outro lado, valores relativamente menores de saturação da transferrina foram associados à presença do alelo MT2736V, independentemente do consumo de ferro biodisponível. Mulheres com β-talassemia menor e suas controles não diferiram quanto à frequência das variantes TMPRSS6 e HFE ou à biodisponibilidade dietética de ferro. Na pós-menopausa, a β-talassemia menor foi associada com valores duas vezes maiores de ferritina, 20% maiores de saturação da transferrina e com probabilidade 3,5 vezes maior de hiperferritinemia. Entretanto, para casos e controles na idade reprodutiva, foi estimada probabilidade de inadequação do consumo de 20,7% e prevalências de deficiência do mineral de 13,3% e 10,0%, respectivamente. Entre essas mulheres, o genótipo positivo ou negativo para a variante MT2736V foi também associado com diferenças nas médias de saturação da transferrina. No entanto, o contraste nesses valores foi relativamente maior entre as mulheres com β-talassemia menor. Além disso, mais acentuada hipocromia acompanhou a presença da variante MT2736V nessa condição. Conclusão: Os achados sugerem que, entre mulheres com eritropoese normal ou com β-talassemia menor, a variante MT2736V não afeta tão fortemente as reservas de ferro corporal como faz a adequação do consumo desse mineral. Ainda assim, a variante HFE63D pode modificar a relação da biodisponibilidade de ferro com seu status corporal e, portanto, ser um importante marcador preditivo de resposta diferencial à dieta. A variante MT2736V foi associada com menor disponibilidade de ferro na circulação de mulheres na idade reprodutiva e, entre aquelas com &#946.;-talassemia menor, com indício de acentuada alteração morfológica dos eritrócitos. / Introduction: Iron deficiency is common among women at childbearing age and it is regarded as a worldwide public health issue. On the other hand, disorders associated with increased erythropoietic activity and iron overload, such as thalassemias and sickle cell disease, are among the most frequent Mendelian diseases in many populations. HFE and TMPRSS6 genes encode the hereditary hemochromatosis protein (HFE) and the matriptase-2 (MT2) both of which modulate the hepatic production of hepcidin, the main hormone regulator of iron metabolism. The aim of this study was to evaluate the relationship among dietary iron intake, rs855791 (MT2736V), rs4820268 (MT2521D), rs1799945 (HFE63D) and rs1800562 (HFE282Y) genetic variants and body iron status of women with normal (apparently healthy) or slightly increased (β-thalassemia minor) erythropoietic activity. Casuistic and methods: Initially, 127 university students at childbearing age (18 to 42 years old) and with steady state body iron (few variations on physiological requirements and dietary iron intake at least for the last 12 months) were included. In a second study, it was included 33 cases of β-thalassemia minor (18 of them post-menopaused) registered in Hematology Services from two hospitals from São Paulo-SP and one from Sorocaba-SP. They were paired with 66 controls by age, body mass index, reproductive status and hormonal contraceptive use. Using food diaries or 24 hours food recalls, total and bioavailable dietary iron intakes were estimated. Blood samples were used for DNA extraction and for determinations of ferritin, transferrin saturation with iron and hemoglobin. TMPRSS6 and HFE genotyping were performed by real time PCR. Results: Considering all the 226 women studied, the allelic frequencies of MT2736V, MT2521D, HFE63D e HFE282Y genetic variants were em 40.3%, 44.0%, 16.3% e 1.5%, respectively. In the first study, a total dietary iron intake of 10.9 mg/day and an iron deficiency prevalence of 12.6% were estimated. There were correlations among ferritin and transferrin saturation values with estimates of bioavailable, but not of total dietary iron intake s. Associations between dietary iron bioavailability and iron biomarkers were especially evident among carriers of HFE63D variant, indicating a significant gene-diet interaction. On the other hand, lower levels of transferrin saturation were associated with the presence of MT2736V variant allele, irrespective of bioavailable iron intake. TMPRSS6 and HFE variants frequencies and dietary iron bioavailability estimates did not differ between women with β-thalassemia minor and their controls. Among postmenopausal women, β-thalassemia minor was associated with two times higher ferritin values, 20% higher transferrin saturation values and 3.5 times higher chance for hiperferritinemia. However, among cases and controls at childbearing age, it was estimated a probability of inadequacy in the dietary iron intake of 20.7% and iron deficiency prevalences of 13.3% and 10.0%, respectively. Among these women, a positive or negative genotype for MT2736V was also associated with differences in transferrin saturation. Nevertheless, the contrast between these values was relatively higher among women with β-thalassemia minor. Moreover, a more accentuated hypochromia accompanied the presence of the MT2736V variant in this condition. Conclusions: Our findings suggest that, among women with normal erythropoiesis or β-thalassemia minor, the presence of the MT2736V variant does not strongly impact the body iron stores as does dietary iron adequacy. Nevertheless, the HFE63D variant may modify the relationship between the dietary iron bioavailability and the body iron status. Therefore, it might be an important predictive marker of women\'s differential response to diet. The MT2736V variant was associated with lower availability of circulating iron in women at childbearing age and, among those with β-thalassemia minor, with suggestive accentuated morphological alteration of erythrocytes.

La present tesi avalua els efectes de certs factors ambientals sobre la paraoxonasa1 (PON1), enzim antioxidant, possiblement protector enfront les malalties cardiovasculars, a través de dos estudis d'intervenció i un de transversal. En primer lloc, el tractament amb simvastatina dels pacients amb hipercolesterolèmia familiar, que presentaven una activitat paraoxonasa baixa, s'associava a un increment de l'activitat fins a valors similars als d'individus normolipèmics, independentment dels polimorfismes PON1-55 o PON1-192. En segon lloc, l'entrenament físic s'associava a un augment de l'activitat paraoxonasa en els individus QQ i una disminució de la mateixa en els portadors de l'al·lel R pel polimorfisme PON1-192. L'increment de l'activitat paraoxonasa immediatament després de l'exercici físic agut era seguit per una disminució subseqüent de l'activitat. La recuperació dels nivells basals d'activitat paraoxonasa a les 24h de l'exercici físic agut es donava en els individus QQ independentment del seu estat d'entrenament, i en els individus portadors de l'al·lel R només quan estan entrenats. En tercer lloc, el consum elevat d'àcid oleic comportava un augment de la concentració de c-HDL i de l'activitat paraoxonasa en els homes portadors dels genotips QR i RR del polimorfisme PON1-192, respectivament.Paraules claus: paraoxonasa, PON1, genotips, simvastatina, hipercolesterolèmia familiar, interacció gen-dieta, lipoproteïna d'alta densitat (HDL), exercici físic agut, entrenament físic, estrès oxidatiu, àcid oleic, oli d'oliva, peròxids lipídics, malaltia cardiovascular. / The present thesis evaluates some environmental factor effects on paraoxonase1 (PON1), an possibly protective against cardiovascular disease antioxidant enzyme, through two intervention studies and a cross-sectional one. First, treatment with simvastatin of the familial hypercholesterolemic patients, which had low paraoxonase activity, was associated with an increase in the activity to values similar to the normolipemic ones, regardless of the PON1-55 or PON1-192 polymorphisms. Second, Regular exercise was associated with an increase in PON1 activity in QQ subjects and with a decrease in R carriers. Increased PON1 activity immediately after a bout of exercise was subsequently followed by a decrease of activity. The recovery of the basal PON1 activity levels at 24 h was found in QQ subjects regardless of their training status and in trained R carriers, but not in untrained R carriers. Third, high oleic acid intake was associated with increased HDL cholesterol and PON1 activity levels only in men who were QR and RR of the PON1-192 polymorphism, respectively.