雙語閱讀：最解渴的飲料居然不是水
什麼飲料最解渴？白水、茶還是汽水？都不是！蘇格蘭科學家的研究發現，最補水的飲料含有乳糖、蛋白質和脂肪，你猜出來是哪種飲料了嗎？
When you're thirsty and in need of a drink, which beverages are best at keeping you hydrated?
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.
當然，你總是可以喝水的——但是根據蘇格蘭聖安德魯斯大學的一項研究，白水並非最解渴的飲料。這項研究將幾種不同飲料的解渴功效做了對比。
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.
研究人員發現，儘管水（包括白水和蘇打水）能夠迅速給身體補水，但是，含有一點糖、脂肪或蛋白質的飲料補水效果更長久。
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.
這項研究的作者、聖安德魯斯大學醫學院教授羅納爾德·莫恩說，原因和我們的身體對飲料的反應機制有關。一個因素是飲料的攝入量：你喝得越多，飲料從胃裡排空並被血流吸收的速度越快，從而稀釋體液，給你補水。
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.
另一個影響飲料補水功效的因素和飲料的營養成分有關。例如，研究人員發現，牛奶的補水功效甚至比白水更佳，因爲牛奶含有乳糖、蛋白質和脂肪，這些成分都有助於減緩液體從胃裡排空的速度，延長補水的功效。
Milk also has sodium, which acts like a sponge and holds onto water in the body and results in less urine produced.
牛奶還含有鈉，鈉可以像海綿一樣在身體裡留住水分，並導致產生的尿液減少。
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.
用來治療腹瀉的口服補水溶液也可以有同樣的補水功效。那些含有少量糖、鈉和鉀的飲料也可以幫助人體留住水分。
想要補水效果好 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.
但是問題就在這裡：糖濃度更高的飲料（比如果汁或可樂）的補水效果就不一定有含糖量低的飲料好了。和白水相比，這些飲料也許在胃裡停留的時間更長一點，排空速度更慢，但一旦這些飲料進入小腸，高濃度的糖就會在滲透作用（一種生理過程）下得到稀釋。這一過程會“抽出”人體的水分來稀釋小腸中的飲料糖分。嚴格意義上來講，小腸內部的任何物質都會排出體外。
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.
果汁和汽水不但補水功效更差，而且會提供過多的糖分和熱量，而且不會像固體食物一樣令我們產生飽腹感。如果要在汽水和水當中選一個來解渴，你肯定要選水。畢竟，我們的腎和肝依靠水來排除身體裡的毒素，而且水對於保持皮膚的彈性和柔軟也起到了關鍵作用。水是你能找到的最便宜的潤膚品。
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.
儘管補水很重要——可以保持關節潤滑，幫助防止感染，將營養輸送到細胞——不過，在大多數情況下人們不需要太擔心飲料的補水效果。
lubricate:vt. 使…潤滑
"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.
莫恩說：“如果你渴了，身體會告訴你多喝一點。”不過，對於在高溫條件下辛苦訓練並大量排汗的運動員，或者對認知功能可能因長時間工作無暇喝水而受損的人而言，補水就變得很重要。
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，會讓你排出更多尿液，因此酒精飲料的補水效果取決於攝入的酒量。莫恩說：“啤酒導致的水分流失比威士忌少，因爲喝啤酒攝入的液體更多。烈酒會讓人體脫水，低度酒精飲料則不會。”
diuretic:n. 利尿劑
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.
至於咖啡的補水效果則取決於你攝入的咖啡因總量。根據莫恩的研究，一杯含有約80毫克咖啡因的普通咖啡的補水效果和水差不多。
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.
攝入超過300毫克的咖啡因，或兩到四杯咖啡，會導致你失去過多水分，因爲咖啡因有溫和的短期利尿作用。不經常喝咖啡的人更容易發生脫水，可以通過加入一兩勺牛奶來抵消。
最補水的飲料排行榜
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.
聖安德魯斯大學的研究團隊測試了13種常見飲料的補水效果。下面是這13種飲料在四個小時內的補水效果排行榜（補水效果依次遞減）：
Skim milk 脫脂牛奶
Oral rehydration solutions 口服補水溶液
Full fat milk 全脂牛奶
Orange juice 果汁
Cola 可樂
Diet Cola 健怡可樂
Cold tea 涼茶
Tea 茶
Sports drink 運動飲料
Still water 白水
Sparkling water 蘇打水
Lager 啤酒
Coffee 咖啡