双语阅读：最解渴的饮料居然不是水
什么饮料最解渴？白水、茶还是汽水？都不是！苏格兰科学家的研究发现，最补水的饮料含有乳糖、蛋白质和脂肪，你猜出来是哪种饮料了吗？
Photo by Boxed Water Is Better on Unsplash
When you're thirsty and in need of a drink, which beverages are best at keeping you hydrated?
如果你感到口渴需要喝点东西，哪种饮料最解渴呢？
Sure, you can always reach for a glass of water -- but plain H20 isn't the most hydrating beverage around, according to a study from Scotland's St. Andrews University that compared the hydration responses of several different drinks.
当然，你总是可以喝水的——但是根据苏格兰圣安德鲁斯大学的一项研究，白水并非最解渴的饮料。这项研究将几种不同饮料的解渴功效做了对比。
The researchers found that while water -- both still and sparkling --does a pretty good job of quickly hydrating the body, beverages with a little bit of sugar, fat or protein do an even better job of keeping us hydrated for longer.
研究人员发现，尽管水（包括白水和苏打水）能够迅速给身体补水，但是，含有一点糖、脂肪或蛋白质的饮料补水效果更长久。
The reason has to do with how our bodies respond to beverages, according to Ronald Maughan, a professor at St. Andrews' School of Medicine and the study's author. One factor is the volume of a given drink: The more you drink, the faster the drink empties from your stomach and gets absorbed into the bloodstream, where it can dilute the body's fluids and hydrate you.
这项研究的作者、圣安德鲁斯大学医学院教授罗纳尔德·莫恩说，原因和我们的身体对饮料的反应机制有关。一个因素是饮料的摄入量：你喝得越多，饮料从胃里排空并被血流吸收的速度越快，从而稀释体液，给你补水。
The other factor affecting how well a beverage hydrates relates to a drink's nutrient composition. For example, milk was found to be even more hydrating than plain water because it contains the sugar lactose, some protein and some fat, all of which help to slow the emptying of fluid from the stomach and keep hydration happening over a longer period of time.
另一个影响饮料补水功效的因素和饮料的营养成分有关。例如，研究人员发现，牛奶的补水功效甚至比白水更佳，因为牛奶含有乳糖、蛋白质和脂肪，这些成分都有助于减缓液体从胃里排空的速度，延长补水的功效。
Photo by Eiliv-Sonas Aceron on Unsplash
Milk also has sodium, which acts like a sponge and holds onto water in the body and results in less urine produced.
牛奶还含有钠，钠可以像海绵一样在身体里留住水分，并导致产生的尿液减少。
The same can be said for oral rehydration solutions that are used to treat diarrhea. Those contain small amounts of sugar, as well as sodium and potassium, which can also help promote water retention in the body.
用来治疗腹泻的口服补水溶液也可以有同样的补水功效。那些含有少量糖、钠和钾的饮料也可以帮助人体留住水分。
Photo by Piotr Chrobot on Unsplash
想要补水效果好 糖多不如糖少
But here's where it gets tricky: Beverages with more concentrated sugars, such as fruit juices or colas, are not necessarily as hydrating as their lower-sugar cousins. They may spend a little more time in the stomach and empty more slowly compared to plain water, but once these beverages enter the small intestine their high concentration of sugars gets diluted during a physiological process called osmosis. This process in effect "pulls" water from the body into the small intestine to dilute the sugars these beverages contain. And technically, anything inside the intestine is outside your body.
但是问题就在这里：糖浓度更高的饮料（比如果汁或可乐）的补水效果就不一定有含糖量低的饮料好了。和白水相比，这些饮料也许在胃里停留的时间更长一点，排空速度更慢，但一旦这些饮料进入小肠，高浓度的糖就会在渗透作用（一种生理过程）下得到稀释。这一过程会“抽出”人体的水分来稀释小肠中的饮料糖分。严格意义上来讲，小肠内部的任何物质都会排出体外。
Juice and soda are not only less hydrating, but offer extra sugars and calories that won't fill us up as much as solid foods. If the choice is between soda and water for hydration, go with water every time. After all, our kidneys and liver depend on water to get rid of toxins in our bodies, and water also plays a key role in maintaining skin's elasticity and suppleness. It's the cheapest moisturizer you'll find.
果汁和汽水不但补水功效更差，而且会提供过多的糖分和热量，而且不会像固体食物一样令我们产生饱腹感。如果要在汽水和水当中选一个来解渴，你肯定要选水。毕竟，我们的肾和肝依靠水来排除身体里的毒素，而且水对于保持皮肤的弹性和柔软也起到了关键作用。水是你能找到的最便宜的润肤品。
While staying hydrated is important -- doing so keeps our joints lubricated, helps prevent infections, and carries nutrients to our cells -- in most situations people don't need to worry too much about how hydrating their beverages are.
尽管补水很重要——可以保持关节润滑，帮助防止感染，将营养输送到细胞——不过，在大多数情况下人们不需要太担心饮料的补水效果。
lubricate:vt. 使…润滑
"If you're thirsty, your body will tell you to drink more," Maughan said. But for athletes training seriously in warm conditions with high sweat losses, or for someone whose cognitive function may be negatively impacted by working long hours without beverage breaks, hydration becomes a critical issue.
莫恩说：“如果你渴了，身体会告诉你多喝一点。”不过，对于在高温条件下辛苦训练并大量排汗的运动员，或者对认知功能可能因长时间工作无暇喝水而受损的人而言，补水就变得很重要。
Photo by Emre Gencer on Unsplash
啤酒和咖啡可以解渴吗？
Alcohol acts as a diuretic, which causes you to pass more urine, so when it comes to alcoholic beverages hydration will depend on a beverage's total volume. "Beer would result in less water loss than whiskey, because you are ingesting more fluid with beer," Maughan said. "Strong alcoholic drinks will dehydrate, dilute alcoholic drinks will not."
酒精有利尿作用，会让你排出更多尿液，因此酒精饮料的补水效果取决于摄入的酒量。莫恩说：“啤酒导致的水分流失比威士忌少，因为喝啤酒摄入的液体更多。烈酒会让人体脱水，低度酒精饮料则不会。”
diuretic:n. 利尿剂
When it comes to coffee, how well your java hydrates you will depend on the amount of caffeine you consume. A regular coffee with about 80 milligrams of caffeine would be pretty much as hydrating as water, according to Maughan's research.
至于咖啡的补水效果则取决于你摄入的咖啡因总量。根据莫恩的研究，一杯含有约80毫克咖啡因的普通咖啡的补水效果和水差不多。
Consuming more than 300mg of caffeine, or about 2-4 cups of coffee, could cause you to lose excess fluid as the caffeine causes a mild, short-term diuretic effect. This is more likely to happen with someone who doesn't typically consume caffeine, and it could be offset by adding a tablespoon or two of milk to your cup of joe.
摄入超过300毫克的咖啡因，或两到四杯咖啡，会导致你失去过多水分，因为咖啡因有温和的短期利尿作用。不经常喝咖啡的人更容易发生脱水，可以通过加入一两勺牛奶来抵消。
最补水的饮料排行榜
The research team at St. Andrews University tested 13 common beverages to see how they impact hydration. Here's what they found, ranked from most hydrating over a four-hour period to least.
圣安德鲁斯大学的研究团队测试了13种常见饮料的补水效果。下面是这13种饮料在四个小时内的补水效果排行榜（补水效果依次递减）：
Skim milk 脱脂牛奶
Oral rehydration solutions 口服补水溶液
Full fat milk 全脂牛奶
Orange juice 果汁
Cola 可乐
Diet Cola 健怡可乐
Cold tea 凉茶
Tea 茶
Sports drink 运动饮料
Still water 白水
Sparkling water 苏打水
Lager 啤酒
Coffee 咖啡
