RESUMEN
High salt intake is a well-recognized risk factor for osteoporosis because it induces calciuria, but the effects of salt on calcium metabolism and the potential impact on bone health in postmenopausal women have not been fully characterized. This study investigated adaptive mechanisms in response to changes in salt and calcium intake in postmenopausal women. Eleven women completed a randomized cross-over trial consisting of four successive 5-wk periods of controlled dietary intervention, each separated by a minimum 4-wk washout. Moderately low and high calcium (518 versus 1284 mg) and salt (3.9 versus 11.2 g) diets, reflecting lower and upper intakes in postmenopausal women consuming a Western-style diet, were provided. Stable isotope labeling techniques were used to measure calcium absorption and excretion, compartmental modeling was undertaken to estimate bone calcium balance, and biomarkers of bone formation and resorption were measured in blood and urine. Moderately high salt intake (11.2 g/d) elicited a significant increase in urinary calcium excretion (p = 0.0008) and significantly affected bone calcium balance with the high calcium diet (p = 0.024). Efficiency of calcium absorption was higher after a period of moderately low calcium intake (p < 0.05) but was unaffected by salt intake. Salt was responsible for a significant change in bone calcium balance, from positive to negative, when consumed as part of a high calcium diet, but with a low calcium intake, the bone calcium balance was negative on both high and low salt diets.
Asunto(s)
Huesos/metabolismo , Calcio/metabolismo , Conducta Alimentaria/efectos de los fármacos , Salud , Posmenopausia/efectos de los fármacos , Cloruro de Sodio Dietético/farmacología , Sodio/metabolismo , Anciano , Biomarcadores/metabolismo , Resorción Ósea/metabolismo , Resorción Ósea/orina , Huesos/efectos de los fármacos , Calcio/orina , Calcio de la Dieta/farmacología , Dieta , Dieta Hiposódica , Femenino , Hormonas/metabolismo , Humanos , Absorción Intestinal/efectos de los fármacos , Cinética , Persona de Mediana Edad , Modelos Biológicos , Osteogénesis/efectos de los fármacos , Fósforo/orina , Posmenopausia/orina , Potasio/orina , Sodio/orinaRESUMEN
To examine the contribution of genetic factors to food choice, we determined dietary patterns from food frequency questionnaires in 3262 UK female twins aged 18 to 79 years. Five distinct dietary patterns were identified (fruit and vegetable, high alcohol, traditional English, dieting, low meat) that accounted for 22% of the total variance. These patterns are similar to those found in other singleton Western populations, and were related to body mass index, smoking status, physical activity and deprivation scores. Older subjects had higher scores on the fruit and vegetable and traditional English patterns, while lower social deprivation was associated with higher scores for fruit and vegetable, and lower scores for traditional English patterns. All 5 patterns were heritable, with estimates ranging from 41% to 48%. Among individual dietary components, a strongly heritable component was identified for garlic (46%), coffee (41%), fruit and vegetable sources (49%), and red meat (39%). Our results indicate that genetic factors have an important influence in determining food choice and dietary habits in Western populations. The relatively high heritability of specific dietary components implicates taste perception as a possible target for future genetic studies.
Asunto(s)
Dieta , Preferencias Alimentarias , Carácter Cuantitativo Heredable , Adolescente , Adulto , Anciano , Estudios de Cohortes , Análisis Factorial , Femenino , Humanos , Persona de Mediana Edad , Encuestas y Cuestionarios , Reino UnidoRESUMEN
BACKGROUND: Women have an increased risk of iron deficiency during pregnancy because of the demands of the developing fetus. Iron supplements are commonly advocated as a prophylactic treatment and are generally taken with meals to reduce side effects, but iron can interfere with the absorption of zinc. OBJECTIVE: The aim was to determine the effect of consuming an iron supplement (100 mg Fe/d as ferrous gluconate) with meals from 16 wk gestation to term on zinc status and absorption. DESIGN: Stable-isotope techniques were used to measure zinc status (exchangeable zinc pool, EZP) and fractional zinc absorption (FZA) in early and late pregnancy from a meal consumed at a different time from that of iron supplement or placebo consumption in 6 women given iron supplements and 7 given a placebo. RESULTS: FZA increased during pregnancy, independent of iron supplementation. FZA was significantly higher (P < 0.001) at week 34 than at weeks 16 and 24, and urinary zinc excretion was higher at week 34 than at week 16 (P = 0.02). The size of the EZP remained unchanged throughout pregnancy and was unaffected by iron supplementation. The iron status of iron-supplemented women was higher than that of the placebo group. CONCLUSIONS: In iron-replete pregnant women who consumed a Western diet, no detectable adverse effects on zinc metabolism were observed after ingestion of 100 mg Fe/d. An increase in the efficiency of zinc absorption was observed during late pregnancy.
Asunto(s)
Absorción Intestinal/efectos de los fármacos , Hierro de la Dieta/farmacología , Estado Nutricional , Embarazo/metabolismo , Zinc/farmacocinética , Administración Oral , Adolescente , Adulto , Suplementos Dietéticos , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Hierro de la Dieta/administración & dosificación , Hierro de la Dieta/efectos adversos , Atención Prenatal , Método Simple Ciego , Zinc/sangre , Zinc/orinaRESUMEN
Consumption of fresh apples can cause allergy in susceptible individuals. A competitive enzyme-linked immunosorbent assay (ELISA) has been developed to determine Mal d 1 levels in apple pulp using a monoclonal antibody (BIP-1). The ELISA was able to rank ten cultivars according to their Mal d 1 content (between 3.8 and 72.5 mug/g pulp). For the first time, it has been demonstrated that growing conditions and postharvest storage, using three different treatments over a 5 month period in 2 consecutive years, increase Mal d 1 expression at a translational and transcriptional level (3.5- and 8.5-fold under controlled atmosphere storage). Expression of three major Mal d 1 isoforms was observed by real-time polymerase chain reaction over the 5 month storage period, and Mal d 1.02 was the most highly expressed isoform. In conclusion, Mal d 1 gene expression was significantly increased during modified atmosphere storage. Individuals suffering from birch pollen-apple allergy syndrome might experience fewer problems consuming freshly picked apples.
Asunto(s)
Alérgenos/análisis , Conservación de Alimentos/métodos , Frutas/inmunología , Malus , Proteínas de Plantas/análisis , Alérgenos/genética , Antígenos de Plantas , Ensayo de Inmunoadsorción Enzimática/métodos , Frutas/química , Expresión Génica , Proteínas de Plantas/genética , ARN Mensajero/análisis , ARN de Planta/análisis , Reproducibilidad de los Resultados , Factores de TiempoRESUMEN
Consumption of apples can provoke severe allergic reactions, in susceptible individuals, due to the presence of the allergen Mal d 3, a nonspecific lipid transfer protein, found largely in the fruit skin. Levels of Mal d 3 were determined in peel as a function of apple cultivar, position of the fruit growing on the tree, apple maturity, and postharvest storage by ELISA. As the apples mature, Mal d 3 levels increased, although the rate was dependent on cultivar and tree position. During storage, levels of Mal d 3 decreased in all cultivars (cvs. Cox, Jonagored, and Gala), the rate of overall decrease being greatest under controlled atmosphere conditions. There was no correlation between Mal d 3 levels and total apple peel protein, indicating specific alterations in Mal d 3 expression. Thus pre- and postharvest treatments (i.e., storage) can modify the allergen load in apple peel, the highest levels being found in overly mature and freshly harvested fruits.
Asunto(s)
Alérgenos/análisis , Conservación de Alimentos/métodos , Frutas/crecimiento & desarrollo , Frutas/inmunología , Malus/inmunología , Antígenos de Plantas , Proteínas Portadoras , Electroforesis en Gel de Poliacrilamida , Ensayo de Inmunoadsorción Enzimática , Factores de TiempoRESUMEN
Women of childbearing age are at risk of Fe deficiency if insufficient dietary Fe is available to replace menstrual and other Fe losses. Haem Fe represents 10-15 % of dietary Fe intake in meat-rich diets but may contribute 40 % of the total absorbed Fe. The aim of the present study was to determine the relative effects of type of diet and menstrual Fe loss on Fe status in women. Ninety healthy premenopausal women were recruited according to their habitual diet: red meat, poultry/fish or lacto-ovo-vegetarian. Intake of Fe was determined by analysing 7 d duplicate diets, and menstrual Fe loss was measured using the alkaline haematin method. A substantial proportion of women (60 % red meat, 40 % lacto-ovo-vegetarian, 20 % poultry/fish) had low Fe stores (serum ferritin <10 microg/l), but the median serum ferritin concentration was significantly lower in the red meat group (6.8 microg/l (interquartile range 3.3, 16.25)) than in the poultry/fish group (17.5 microg/l (interquartile range 11.3, 22.4) (P<0.01). The mean and standard deviation of dietary Fe intake were significantly different between the groups (P=0.025); the red meat group had a significantly lower intake (10.9 (sd 4.3) mg/d) than the lacto-ovo-vegetarians (14.5 (sd 5.5) mg/d), whereas that of the poultry/fish group (12.8 (sd 5.1) mg/d) was not significantly different from the other groups. There was no relationship between total Fe intake and Fe status, but menstrual Fe loss (P=0.001) and dietary group (P=0.040) were significant predictors of Fe status: poultry/fish diets were associated with higher Fe stores than lacto-ovo-vegetarian diets. Identifying individuals with high menstrual losses should be a key component of strategies to prevent Fe deficiency.
Asunto(s)
Anemia Ferropénica/sangre , Dieta , Hierro de la Dieta/administración & dosificación , Menstruación/metabolismo , Adolescente , Adulto , Análisis de Varianza , Animales , Dieta Vegetariana , Femenino , Ferritinas/sangre , Peces , Humanos , Modelos Lineales , Estado Nutricional , Aves de CorralRESUMEN
The normal degree of intra- and interindividual variation in gene transcription profiles of healthy human tissues has not been extensively investigated. In the study described here, microarrays were employed to analyze gene transcription in peripheral blood mononuclear cells prepared from serial blood samples that had been obtained, at weekly intervals, from apparently healthy human volunteers. Transcript levels for the majority of genes examined were found to be remarkably consistent within samples from a single donor. Conversely, marked differences were observed in samples obtained from different donors. Genes that exhibited differential expression dependent on sex, age, body mass index, and the presence of varying proportions of different leukocyte subsets were identified. These results emphasize the important contributions of genetic and environmental factors, as well as varying representation of different cell types, in determining the overall gene transcriptional profiles of human tissues. However, the study also provides evidence that, within an individual, the gene transcription profiles of sampled tissues can be comparatively stable over time.