The latest on hydration

Dear Alice,

I frequently hear that beverages with caffeine or alcohol are not good for replenishing fluids and preventing dehydration. But in reality aren't they just a bit less effective at hydrating your body than other beverages? In other words, if you were stuck in the desert with nothing to drink but beer, coffee and cola, would you actually be worse off and die of thirst sooner if you drank these beverages versus not drinking anything at all?

Feel free to reword the question!

Dear Reader,

Even just the thought of being stranded in the desert without water may cause thirst for some people — water is that essential to life. Water is one of the most vital nutrients in the body and is needed in almost all bodily functions. It makes up approximately 75 percent of the brain and 70 percent of muscles. Every day, your body uses and loses water through sweating, urinating, and breathing. Some drinks, specifically those that are caffeinated or alcoholic, are diuretics, which means they increase the amount of water that’s lost from your body through urine. However, there are additional factors to consider if dehydration from these drinks is a concern. To sort out your dilemma, it may help to flesh, or rather flush out some of these details.

The drinks you mention — beer, coffee, and cola — are mild diuretics to varying degrees because they contain enough water to compensate for the fluid lost through urination. In fact, research has shown they don’t cause dehydration at moderate levels of consumption (think four or five cups of coffee per day). However, stronger diuretics — such as wine and liquor — tend to vary in water and alcohol content and thus, warrant more caution. A key factor to consider is the ratio of water to alcohol consumed. For instance, beer tends to contain more water than alcohol, while liquor may cause dehydration without additional water.

Another aspect of this topic to consider is each person's unique water needs. For example, folks who live in hot climates, are quite active, sweat a lot, are pregnant or breastfeeding, or are ill may need more water than the average adult. In most healthy adults, however, the “eight by eight” is a good rule-of-thumb for staying hydrated: drink eight, eight-ounce glasses of fluid a day. Keep in mind, the “fluid” part doesn’t just mean water. Approximately 80 percent of an individual's total water intake comes from drinking various fluids, while the other 20 percent comes from food. Keeping yourself hydrated is a healthy habit, but try sticking to fluids that are low in sugar, sodium, and diuretic properties. Besides, water is refreshing, inexpensive, and readily available (at least in the United States).

If you’re trying to determine your hydration levels, a fairly simple test is to the color of your urine — if it's dark yellow or orange, you may be dehydrated. Urine that’s very light yellow or clear and colorless (like water) is a sign of a hydrated body. Other signs to look out for include having a dry or sticky mouth and feeling dizzy and lightheaded. While dehydration is often not considered a serious condition, it can have serious effects over time, such as decreased physical and mental performance. 

Here's to hoping you never have to be stranded in the desert.

Last updated Sep 16, 2016
Originally published Aug 20, 2004