Evaluación de la ingesta dietética y excreción urinaria de sodio y potasio en adultos / Assessment of dietary intake and urinary excretion of sodium and potassium in adults

Background: Hypertension is associated with elevated sodium and low potassium intakes. The determination of sodium and potassium intake by dietary records is inaccurate, being its measurement from 24-h urine collection the reference method. Aim: To determine urinary sodium and potassium excretion in adults. To compare dietary sodium and potassium intake and their excretion from an isolated urine sample against the reference method. Material and Methods: Seventy healthy adults aged 35 ± 8 years with a body mass index 25 ± 2 kg/m² (36 women) were studied. Urine was collected over 24 h, including an isolated urine sample taken in fasting conditions. Additionally, three 24-h dietary records were performed. Results: Reported sodium and potassium intake was 2,720 ± 567 and 1,068 ± 433 mg/day, respectively. In turn, urinary excretion of sodium and potassium was 4,770 ± 1,532 and 1,852 ± 559 mg/day, respectively. These latter values were significantly higher than those obtained by dietary records. Furthermore, the urinary sodium and potassium excretion estimated from an isolated urine sample was 4,839 ± 1,355 and 1,845 ± 494 mg/day, respectively. These values were similar to those obtained with a 24 h urine collection. Conclusions: Dietary records underestimated electrolyte intake when compared with the reference method. Using an isolated urine sample to estimate electrolyte intake may be a reliable alternative.

Not Salt Taste Perception but Self-Reported Salt Eating Habit Predicts Actual Salt Intake

Excessive dietary salt intake is related to cardiovascular morbidity and mortality. Although dietary salt restriction is essential, it is difficult to achieve because of salt palatability. However, the association between salt perception or salt eating habit and actual salt intake remains uncertain. In this study, we recruited 74 healthy young individuals. We investigated their salt-eating habits by questionnaire and salt taste threshold through a rating scale that used serial dilution of a sodium chloride solution. Predicted 24-hr urinary salt excretions using Kawasaki's and Tanaka's equations estimated dietary salt intake. Participants' mean age was 35 yr, and 59.5% were male. Salt sense threshold did not show any relationship with actual salt intake and a salt-eating habit. However, those eating "salty" foods showed higher blood pressure (P for trend=0.048) and higher body mass index (BMI; P for trend=0.043). Moreover, a salty eating habit was a significant predictor for actual salt intake (regression coefficient [beta] for Kawasaki's equation 1.35, 95% confidence interval [CI] 10-2.69, P=0.048; beta for Tanaka's equation 0.66, 95% CI 0.01-1.31, P=0.047). In conclusion, a self-reported salt-eating habit, not salt taste threshold predicts actual salt intake.

Estimation of Daily Salt Intake through a 24-Hour Urine Collection in Pohang, Korea

There is an established relationship between a high salt diet and public health problems, especially hypertension and cardiovascular disease. We estimated daily salt intake in a group of adults and assessed its association with related variables in Pohang, Korea. We conducted a cross-sectional survey in 2013 with 242 adults. Urine was collected for 24 hr to estimate daily salt intake, and questionnaires about salt preference were administered. The mean daily salt intake was 9.9+/-4.6 g. There was no difference in salt intake between high systolic blood pressure (SBP) participants and normal SBP participants (10.5+/-4.7 g/d vs. 9.6+/-4.3 g/d, P=0.339), but high diastolic blood pressure (DBP) participants reported more salt intake than normal DBP participants (10.4+/-4.9 g/d vs. 9.7+/-4.1 g/d, P=0.049). Salt intake and body mass index demonstrated a positive correlation (P=0.001). A preference for Korean soup or stew was associated with high salt intake (P=0.038). Dietary salt intake in Korean adults is still higher than the recommendation from the World Health Organization. More efforts should be made to reduce the salt consumption of Korean adults.

Systematic review of studies comparing 24-hour and spot urine collections for estimating population salt intake / Revisión sistemática de estudios comparativos entre recolección de muestras de orina de 24 horas y puntual para calcular el consumo de sal en la población

Objective. To examine the usefulness of urine sodium (Na) excretion in spot or timed urine samples to estimate population dietary Na intake relative to the gold standard of 24-hour (h) urinary Na. Methods. An electronic literature search was conducted of MEDLINE (from 1950) and EMBASE (from 1980) as well as the Cochrane Library using the terms “sodium,” “salt,” and “urine.” Full publications of studies that examined 30 or more healthy human subjects with both urinary Na excretion in 24-h urine and one alternative method (spot, overnight, timed) were examined. Results. The review included 1 380 130 participants in 20 studies. The main statistical method for comparing 24-h urine collections with alternative methods was the use of a correlation coefficient. Spot, timed, and overnight urine samples were subject to greater intraindividual and interindividual variability than 24-h urine collections. There was a wide range of correlation coefficients between 24-h urine Na and other methods. Some values were high, suggesting usefulness (up to r = 0.94), while some were low (down to r = 0.17), suggesting a lack of usefulness. The best alternative to collecting 24-h urine (overnight, timed, or spot) was not clear, nor was the biological basis for the variability between 24-h and alternative methods. Conclusions. There is great interest in replacing 24-h urine Na with easier methods to assess dietary Na. However, whether alternative methods are reliable remains uncertain. More research, including the use of an appropriate study design and statistical testing, is required to determine the usefulness of alternative methods.

Objetivo. Analizar la utilidad de la medicion de la excrecion urinaria de sodio a partir de la recoleccion puntual o cronometrada de muestras de orina para calcular la ingesta de sodio alimentario en la poblacion, en relacion con la prueba de referencia que mide la excrecion de sodio en orina de 24 horas. Métodos. Se realizo una busqueda de bibliografia electronica en MEDLINE (desde 1950) y EMBASE (desde 1980), asi como en la Biblioteca Cochrane, empleando los terminos “sodium”, “salt” y “urine” (sodio, sal y orina). Se examinaron las publicaciones completas de los estudios que incluian 30 o mas sujetos humanos sanos en los que se hubiera determinado la excrecion de sodio mediante la recoleccion de orina de 24 horas o un metodo alternativo (recoleccion puntual, de toda la noche, cronometrada). Resultados. La revision incluyo a 1 380 130 participantes de 20 estudios. El principal metodo estadistico adoptado para comparar las recolecciones de orina de 24 horas con los metodos alternativos fue el uso de un coeficiente de correlacion (r). Las muestras de orina recolectadas de forma puntual, cronometrada y de toda la noche estaban sujetas a mayor variabilidad intra e interindividual que las recolecciones de orina de 24 horas. Se obtuvo una amplia gama de coeficientes de correlacion entre las determinaciones de sodio en orina de 24 horas y mediante los otros metodos. Algunos valores fueron elevados, lo que indica su utilidad (r de hasta 0,94), mientras que otros fueron bajos (r por debajo de 0,17), lo que indica su falta de utilidad. La mejor alternativa a la obtencion de orina de 24 horas (de toda la noche, cronometrada, o puntual) no resulto evidente, ni tampoco la base biologica de la variabilidad entre el metodo de 24 horas y los alternativos. Conclusiones. Hay mucho interes en remplazar la determinacion de sodio en orina de 24 horas por otros metodos mas faciles de evaluacion del sodio alimentario. Sin embargo, sigue habiendo incertidumbre sobre la fiabilidad de los metodos alternativos. Es preciso ampliar la investigacion, incluido el uso de un diseno de estudio y pruebas estadisticas apropiados, para determinar la utilidad de los metodos alternativos.

Excreción urinaria de sodio en niños y adultos de una comuna de la Región Metropolitana de Santiago de Chile / Urinary sodium excretion in children and adults from a bourough of the Metropolitan Region of Chile

Arterial hypertension has increased sharply in Chile, during the last 3 decades. The National Health Survey (2003) registered a 33.7 percent prevalence in Chilean population over 17 years of age. It is known that an excessive sodium intake is a risk factor for arterial hypertension (AH). Objective: To measure urinary sodium excretion in an exploratory study in school age children and adults of a borough of the Metropolitan Region, and later on increase to a representative population sample. Subjects and method: 158 school age children of both sexes aged 10.6 +/- 2.5 years and 48 adults older than 20 years were evaluated. Weight was measured in 0.1 kg precision scale (SECA model 286). Body Mass Index (BMI) was calculated according to the formula weight (kg)/stature (m)2. Arterial pressure was measured with a mercury manual sphygmomanometer. Urinary sodium in 24 hours was calculated with the formula of Tanaka et al. This information was used to predict theoretical NaCI intake using the equation Na mg/day = Na mEq/d x 23; NaCI = Na g/d x 100139.3. Results: BMI in children was 19.2 +/- 4,9 In 28.6 percent and 40.5 percent of adults diastolic and systolic pressure were higher than 90 mm Hg and over 130 mm Hg, respectively. In 1.7 percent and 0.9 percent of children systolic and diastolic pressure were high, according to age and sex. Salt intake per day was calculated assuming that all sodium ingested was consumed as NaCI. Children NaCI intake was 3 +/- 2.2 g per day and in adults was 10.4 +/- 2.5 g per day. Conclusions: BMI was elevated in children and adults in accordance with the high obesity prevalence in the country. The high percentages of elevated blood pressure present in adults were in accordance with high prevalence of hypertension in Chilean adults. Salt intake was high in children and adults constituting a risk factor of hypertension in our population.

En las últimas 3 décadas en Chile, la hipertensión arterial se incrementó notoriamente. La Encuesta Nacional de Salud (año 2003) registró que esta enfermedad afectaba al 33.7 por ciento de la población chilena mayor de 17 años. Se conoce que la ingesta excesiva de Na constituye un factor de riesgo para el desarrollo de hipertensión arterial (HTA). Objetivo: Medir la excreción urinaria de Na en escolares y adultos de una comuna de la Región Metropolitana en estudio exploratorio, para posteriormente ampliarlo a una muestra representativa poblacional. Sujetos y método: Se evaluaron 158 escolares de ambos sexos con edad promedio de 10.6 +/- 2.5 años y 48 adultos mayores de 20 años. El peso se determinó con una báscula con precisión de 0.10 kg (SECA, modelo 286). El índice de Masa Corporal (IMC) se calculó con la ecuación: peso (kg)/talla². La presión arterial se midió con un esfigmomanómetro manual de mercurio. La excreción urinaria de Na en 24 horas fue calculada utilizando la ecuación de Tanka T y col. Este dato se utilizó para predecir la ingesta teórica de NaCI, utilizando las siguientes ecuaciones: Na mg/día = Na mEq/d x 23, NaCl = Na g/d x 100/ 39.3. Resultados: El IMC en niños fue de 19.2 +/- 4.9 y en adultos de 29.0 +/- 5.9. En el 28.6 por ciento y en el 40.5 por ciento de los sujetos adultos evaluados se registró una cifra alta de de presión diastólica (> 90 mm Hg) y sistólica (130 > mm Hg), respectivamente. En 1.7 por ciento de los niños se detectó presión sistólica elevada y en 0.9 por ciento de la diastólica, de acuerdo a la edad y sexo. Se calculó la ingesta de sal por día, suponiendo que todo el sodio ingerido se consumió como NaCI. Los niños evaluados ingirieron 7.3 +/- 2.2 gramos de NaCl por día y los adultos 10.4 +/- 2.5 gramos de NaCI por día. Conclusiones: El IMC era elevado en adultos y niños, de acuerdo con las altas tasas de obesidad de nuestra población. Las porcentajes de presión elevada fueron mucho mayores en los adultos y ...

Effects of salted food consumption on urinary iodine and thyroid function tests in two provinces in the Islamic Republic of Iran

We evaluated sources of difference in urinary iodine between two neighbouring Iranian provinces, Gilan and Mazandaran. In the cities of Rasht [Gilan] and Sari [Mazandaran], 340 and 343 participants respectively were selected by cluster sampling. Urinary iodine in Rasht was significantly higher than in Sari [31 micro g/dL versus 21 micro g/dL]. Sodium and potassium urine levels in Rasht were also higher than Sari. Mean daily intake of iodized salt and thyroid function tests were not significantly different. Average annual consumption of some salted foods was significantly higher in Rasht than Sari. We conclude that higher consumption of salted foods in Rasht is responsible for an increase in urinary iodine

Familial predisposition to hypertension and the association between urinary sodium excretion and blood pressure in a population-based sample of young adults

The reasons for the inconsistent association between salt consumption and blood pressure levels observed in within-society surveys are not known. A total of 157 normotensive subjects aged 18 to 35 years, selected at random in a cross-sectional population-based survey, answered a structured questionnaire. They were classified as strongly predisposed to hypertension when two or more first-degree relatives had a diagnosis of hypertension. Anthropometric parameters were obtained and sitting blood pressure was determined with aneroid sphygmomanometers. Sodium and potassium excretion was measured by flame spectrophotometry in an overnight urine sample. A positive correlation between blood pressure and urinary sodium excretion was detected only in the group of individuals strongly predisposed to hypertension, both for systolic blood pressure (r = 0.51, P<0.01) and diastolic blood pressure (r = 0.50, P<0.01). In a covariance analysis, after controlling for age, skin color and body mass index, individuals strongly predisposed to hypertension who excreted amounts of sodium above the median of the entire sample had higher systolic and diastolic blood pressure than subjects classified into the remaining conditions. The influence of familial predisposition to hypertension on the association between salt intake and blood pressure may be an additional explanation for the weak association between urinary sodium excretion and blood pressure observed in within-population studies, since it can influence the association between salt consumption and blood pressure in some but not all inhabitants.