Para cualquier persona sana, la sed es una guía adecuada para tomar agua, excepto para los bebés, los deportistas y la mayoría de las personas enfermas y ancianas. En estos casos conviene programar momentos para ingerir agua, ya que la gran demanda y los mecanismos fisiológicos que determinan la sed en estas situaciones pueden condicionar desequilibrios en el balance hídrico con importantes consecuencias para la salud o el rendimiento físico o intelectual. Nuestro organismo posee una serie de mecanismos que le permiten mantener constante el contenido de agua, mediante un ajuste entre los ingresos y las pérdidas. El balance hídrico viene determinado por la ingestión (agua de bebida, líquidos, agua contenida en los alimentos) y la eliminación (orina, heces, a través de la piel y de aire espirado por los pulmones). El fallo de estos mecanismos y las consiguientes alteraciones del balance acuoso, pueden producir graves trastornos capaces de poner en peligro la vida del individuo. En el presente documento se analizan las evidencias en cuanto a los factores que condicionan las necesidades hídricas en las diferentes etapas de la vida y situaciones fisiológicas, así como las consecuencias de un desequilibrio en el balance hídrico en diferentes situaciones. Una correcta hidratación la podemos conseguir mediante nuestra alimentación y el uso de agua u otras bebidas. Aunque el agua es la bebida por excelencia y representa la forma ideal de reponer nuestras pérdidas e hidratarnos, debemos de ser conscientes de que, desde el principio de los tiempos, hemos buscado otras fuentes de líquidos con capacidad de hidratación. En las últimas décadas ha aumentado el consumo de diferentes bebidas, proliferando las bebidas con azúcar. Dado que el consumo excesivo de azúcar se ha relacionado con la obesidad y otras enfermedades crónicas, es evidente que debe racionalizarse el uso de estas bebidas calóricas especialmente en niños. En este documento se presentan todas estas consideraciones en cuanto a la hidratación, y se realizan diferentes recomendaciones al respecto.<br>For any healthy individual, thirst is an appropriate sign to drink water, except for babies, sportsmen, and most of ill and elderly people. In these instances, it is convenient to schedule appropriate times to drink water since great demands and the physiological mechanisms that determine thirst in these situations may condition water unbalances with important consequences for health and the physical and intellectual performance. The human body has a number of mechanisms that allow keeping constant the water content by adjusting intakes and wastes. Water balance is determined by intake (consumed water, beverages, and water contained in foods) and wastes (urine, stools, the skin, and expired air from the lungs). Failure of these mechanisms and subsequent impairments in water balance may produce severe disarrangements that may threaten somebody´s life. In the present document, we analyze the evidences regarding the factors conditioning water needs in the different life stages and physiological situations, as well as the consequences of water unbalance under different situations. A proper hydration may be achieved by feeding and the use of water and other liquids. Although water is the beverage by excellence and represents the ideal way of restoring the losses and get hydrated, we should be aware that, from the very beginning, we have sought other liquid sources with hydration properties. In the last decades we have increased the consumption of different beverages, with a proliferation of sugar-containing beverages. Since excessive sugar consumption has been related to obesity and other chronic conditions, it is evident that the use of these caloric beverages should be rationalized, especially in children. In this document all the considerations regarding hydration are presented and different recommendations are exposed.

RESUMEN Propósito: evaluar la efectividad, tolerancia y aceptación de dos bebidas ricas en potasio, comparadas con una bebida deportiva y agua, durante la rehidratación post-ejercicio. Metodología: en cuatro días diferentes, separados entre sí por una semana, 12 voluntarios (10 hombres y 2 mujeres), físicamente activos, con 24.4±3.2 años, 74.75±11.36 kg de masa corporal (promedio±D.E), fueron deshidratados al 2.01%±0.24 de la masa corporal, mediante ejercicio en un laboratorio de clima controlado (32.01±0.41 ºC bs, 53.83±5.15% hr). Cada día ellos fueron rehidratados con una de cuatro bebidas, en orden aleatorio: agua de coco (AC), agua comercial embotellada (AE), una bebida deportiva (BD) o una bebida modificada (BM), utilizando un volumen equivalente al 120% del peso perdido durante el ejercicio, distribuido en 4 porciones iguales consumidas cada 15 minutos. Antes del ejercicio, durante la rehidratación y al final de la sesión se interrogó sobre la percepción de sed, náuseas, llenura, dolor de estómago y urgencia de defecación. Se evaluó además el agrado del sabor, el nivel de dulzura y aceptación general de la bebida, antes del ejercicio y después de cada porción. Posteriormente, los participantes fueron monitoreados por 3 horas, recolectando orina cada 30 minutos. Resultados: los volúmenes de orina fueron mayores (p<0.05) con AE (894±178 mL), que con BD (605±297 mL) y BM (599±254 mL). Por su parte AC (686 ±250 mL), no fue diferente a las demás bebidas (p>.05). La única bebida que fue superior a la AE en el porcentaje de conservación de líquido fue la BD (51.3±% vs. 68.2±% respectivamente, p=.013), ya que al comparar el AC y BM (62.54±15% vs. 65.89±15% respectivamente) con el agua no se hallaron diferencias (p>.05). Ninguna de las bebidas logró la recuperación del peso perdido durante el ejercicio, pero AE produjo un mayor déficit (p=.001) al compararla con BD. No hubo interacción entre las bebidas y el tiempo sobre las percepciones de tolerancia y aceptación medidas en diferentes momentos (p>.05). Conclusiones: ni el agua de coco, ni la bebida modificada, ambas con alto contenido de potasio, pudieron superar los resultados encontrados con la bebida deportiva. Esto demuestra que el potasio en altas concentraciones no produce ventajas adicionales en el proceso de rehidratación, comparado con las ya obtenidas por una bebida que contiene sodio, incluso cuando los dos electrolitos se encuentran juntos en la misma bebida. | ABSTRACT Purpose: To evaluate effectiveness, tolerance and acceptance of two drinks rich in potassium, compared with a sports drinks and bottled water during post-exercise rehydration. Methodology: On four different days, one week apart, 12 healthy students, female (2) and male (10), physically active, young (24.4±3.2 years old) 74.75±11.36 kg of body mass (mean±S.D) students were dehydrated to 2.01±0.24% body mass by exercising in a climate-controlled laboratory (32.01±0.41 ºC dry bulb, 53.83±5.15% rh). Each day they were rehydrated with one of four beverages, in random order: fresh coconut water (CW), bottled water (BW), a sports drink (SD) and sports drink rich in potassium (SDK+) using a volume equivalent to 120% of weight lost during exercise, distributed in 4 equal aliquots, one every 15 minutes. After exercise, after rehydration, before drinking each volume and at the end of the session participants were asked about perception of thirst, nausea, fullness, stomach ache, and urge to defecate; after exercise and after completing each volume, they reported the level of satisfaction of flavor and sweetness, and general acceptability of the drink. Participants were then monitored for three hours, collecting urine every 30 minutes. Comparisons were made with repeated-measures ANOVAs for fluid retention, total urine, and partial times subjective measures and urine production. Results: Urine volumes were higher (p<0.05) for BW (894±178 mL) than SD (605±297 mL) and SDK+ (599±254 mL). On the other hand CW (686 ±250 mL) was not significantly different from the other beverages (p>0.05). The only beverage that was better than BW from the percentage of fluid retained was SD (51.3±% vs. 68.2±% respectively, p=.013), because the comparison between AC y SDK+ (62.54±15% vs. 65.89±15% respectively) with BW did not show significant differences (p>.05). None of the drinks maintained recovery of weight lost during exercise, but BW produced a greater deficit of fluids when that was compared with SD. There was no interaction between beverages and time over tolerance perceptions or acceptability of beverages evaluated in different moments (p>.05). Conclusions: neither CW nor SD, both with high concentrations of potassium, were able to overcome the results found for SD. This shows that potassium in high quantity in some beverages does not produce additional benefits in the rehydration process when these are compared to a SD with sodium, even when both electrolytes are together in the same beverage.

Objetivo: comparar la efectividad rehidratante del agua de coco fresca, con el agua embotellada y una bebida deportiva. Metodología: once participantes de 22,0 ± 1,9 años y 65,6 ± 13,0 kg de masa corporal (promedio ± D.E), asistieron al laboratorio en tres ocasiones, separadas entre sí por una semana. En cada sesión se deshidrataron por ejercicio en el calor hasta perder 1,84 ± 0,2% de la masa corporal. Luego fueron rehidratados en una hora, con agua comercial embotellada (AE), una bebida deportiva (BD) o agua de coco (AC), utilizando un volumen equivalente al 120% del peso perdido. Se evaluaron las sensaciones percibidas relacionadas con la tolerancia y la aceptación de las bebidas. Se recolectó la orina eliminada durante tres horas post-rehidratación. Resultados: Hubo interacción entre las bebidas y el tiempo sobre la orina excretada (p=0,003), siendo el AE estadísticamente diferente al AC y la BD a los 30 y 60 min post-rehidratación (p<0,05). El volumen total de orina fue mayor con agua embotellada (625 ± 183 mL), en comparación con AC y BD (390 ± 73 mL y 416 ± 200 mL, respectivamente, p<0,002); AC y BD no fueron distintas entre sí (p>0,05). Esto produjo porcentajes de conservación de líquido diferentes para AE (56%),con respecto a BD (71%) y AC (71%) (p<0,001). No hubo interacción entre las bebidas y el tiempo sobre las sensaciones percibidas de tolerancia (p>0,05). La percepción de la dulzura fue menor para AE (p= 0,024). BD obtuvo mejores puntajes de sabor y aceptación general (p<0,05). Conclusiones: el agua de coco fresca resulta tan efectiva como una bebida deportiva para conservar el líquido consumido, teniendo una buena tolerancia y aceptación. Podría ser usada como una bebida rehidratante, cuando la persona la tenga disponible y le agrade su sabor. | Objective: To compare the effectiveness of fresh coconut water as a rehydration beverage with bottled water and a sports drink. Method: eleven participants, 22.0±1.9 years of age and 65.6±13.0 kg body mass (average ± S.D.), reported to the laboratory on three separate occasions, each one week apart. Each time they exercised in the heat until they were dehydrated by 1.84 ± 0.2% of initial body mass. They were then rehydrated for one hour with commercial bottled water (BW), a sports drink (SD), or coconut water (CW), using a volume equivalent to 120% of weight loss. Perceived beverage acceptance and tolerance ratings were evaluated, and urine was collected over three hours following rehydration. Results: Urine volumes showed an interaction between beverage and time (p=0.003); BW was statistically different from CW and SD, 30 and 60 minutes after rehydration (p<0.05). Total urine volume was higher for BW (625 ± 183 mL) compared with both CW and SD (390 ± 73 mL and 416 ± 200 mL, respectively, p<0.002); CW and SD were not different from each other (p>0.05). This resulted in a different fluid conservation percentage for BW (56%) compared with CW (71%) and SD (71%) (p<0.001). Perceived tolerance ratings showed no interaction between beverage and time (p>0.05). Perceived sweetness was lower for BW (p= 0.024); SD had higher scores for flavor and overall acceptance (p<0.05). Conclusions: fresh coconut water is as effective as a sports drink in terms of fluid retained following consumption, and it has good tolerance and acceptance; it could be used for rehydration provided it is accessible to the individual and the person finds the flavor pleasing.

O processamento térmico adequado contribui para aumentar a digestibilidade e eliminar fatores antinutricionais presentes em grãos. Porém, esse processo pode ser prejudicial, causando a perda de nutrientes. A irradiação de grãos pode facilitar sua cocção, reduzindo o tempo de amolecimento. O objetivo do presente trabalho foi avaliar possíveis alterações causadas pela irradiação no tempo de cocção e embebição de grãos de soja convencionais e sem lipoxigenase. As duas cultivares analisadas ('BRS 232' - com lipoxigenase e 'BRS 257' - sem lipoxigenase) diferiram entre si na quantidade de água absorvida, no tempo de embebição e no tempo de cocção dos grãos. A irradiação dos grãos, nas doses de 4kGy e 8kGy, diminuiu a absorção de água e o tempo de cocção.<br>The appropriate heat processing helps to improve the digestibility and eliminate antinutritional factors present in grain. However, this process can be harmful, causing nutrient losses. The irradiation on grain can facilitate their cooking, and reduces the time for its softening. The objective of this study was to evaluate possible changes caused by irradiation in the time of hydration and cooking in conventional soybean and soybeans without lipoxygenase. The two cultivars ('BRS 232' - with lipoxygenase and 'BRS 257' - without lipoxygenase) differ in the amount of water absorbed, in time of hydration and time of cooking. Irradiation caused lower water absorption, but less time for cooking.

The appropriate heat processing helps to improve the digestibility and eliminate antinutritional factors present in grain. However, this process can be harmful, causing nutrient losses. The irradiation on grain can facilitate their cooking, and reduces the time for its softening. The objective of this study was to evaluate possible changes caused by irradiation in the time of hydration and cooking in conventional soybean and soybeans without lipoxygenase. The two cultivars ('BRS 232' - with lipoxygenase and 'BRS 257' - without lipoxygenase) differ in the amount of water absorbed, in time of hydration and time of cooking. Irradiation caused lower water absorption, but less time for cooking. | O processamento térmico adequado contribui para aumentar a digestibilidade e eliminar fatores antinutricionais presentes em grãos. Porém, esse processo pode ser prejudicial, causando a perda de nutrientes. A irradiação de grãos pode facilitar sua cocção, reduzindo o tempo de amolecimento. O objetivo do presente trabalho foi avaliar possíveis alterações causadas pela irradiação no tempo de cocção e embebição de grãos de soja convencionais e sem lipoxigenase. As duas cultivares analisadas ('BRS 232' - com lipoxigenase e 'BRS 257' - sem lipoxigenase) diferiram entre si na quantidade de água absorvida, no tempo de embebição e no tempo de cocção dos grãos. A irradiação dos grãos, nas doses de 4kGy e 8kGy, diminuiu a absorção de água e o tempo de cocção.