Moderate Coffee Consumption does Not Cause Dehydration, Study

A latest study dispels a myth about the most popular and often-debated beverage- Coffee. The study offers some good news for all the coffee addicts by saying that moderate consumption of coffee does not cause dehydration.

The study conducted by researchers at the University of Birmingham School of Sports and Exercise Sciences, UK, claim that drinking moderate amount of coffee contributes to the daily requirement of fluids and does cause dehydration in the regular coffee drinkers.

Studies in the past have highlighted the acute effect of caffeine as mild diuretic, due to people thought that beverages like coffee could produce similar effects. Prior to this research, two studies had looked at the effects of caffeine, in the form of coffee, on the hydration status. But their results were convoluted and inconclusive. This is the first study that directly analyzed the effects of moderate intake of coffee compared to the consumption of equal volumes of water.

Sophie Killer a Doctoral researcher and lead author of the study said in a statement, "Despite a lack of scientific evidence, it is a common belief that coffee consumption can lead to dehydration and should be avoided, or reduced, in order to maintain a healthy fluid balance. Our research aimed to establish if regular coffee consumption, under normal living conditions, is detrimental to the drinker's hydration status."

The study was conducted on a group of regular coffee drinkers. The researchers analyzed the effects of moderate consumption of black coffee when compared to the consumption of equal amount of water on body fluid levels. During the study 50 men were tested in two phases. In the first phase they were asked to drink four mugs (200ml) of either black coffee or water per day. This was done for three days. In the second phase they were separated by a ten day 'wash out' period.  Next, the participants were given a wash-out period of ten days. In the second phase, the men were asked from coffee to water or vice versa.

The hydration status was measured using multiple hydration measures including body mass and total body water, blood and urine analyses.

At the end of the analyses the researchers found no difference in total body water or blood measures of hydration status in the group who drank coffee or who drank water. Even in the 24-hour urine volume or urine concentration, no difference was observed.

"We found that consumption of a moderate intake of coffee, four cups per day, in regular coffee drinking males, caused no significant differences across a wide range of hydration indicators compared to the consumption of equal amounts of water," said Sophie Killer. "We conclude that advice provided in the public health domain, regarding coffee and dehydration, should be updated to reflect these findings."

The study was published in the journal PLOS One.