Moderate coffee consumption does not cause dehydration

New research from the University of Birmingham, UK, published on Thursday, in the scientific journal "PLoS ONE", shows that there is no relationship between moderate coffee consumption and dehydration.
This study began because of a previous research that showed the acute effects of caffeine as a mild diuretic, and a common assumption that caffeinated drinks such as coffee, had this effect. However, the effect of coffee consumption in fluid balance cannot be compared directly with that of pure caffeine.
This is the first study to directly evaluate the effects of moderate consumption of coffee compared to equal volumes of water. The researcher Sophie Killer, lead author of the study, commented that "despite the lack of scientific evidence, it is a common belief that coffee consumption can lead to dehydration and should be avoided or reduced to maintain a balance of healthy fluids. Our research aimed to verify whether the regular consumption of coffee, in normal life, is detrimental to the hydration status of the consumer," she explains.
In a sample of regular coffee drinkers, Sophie Killer and his colleagues measured the effects of moderate consumption of coffee compared to equal volumes of water for fluid balance and hydration status. Fifty male subjects were tested in two phases, where they were required to drink four mugs (200 ml) of water or coffee a day for three days. In the second phase, those who had drunk coffee initially exchanged for drinking water and vice versa. The two phases were separated for a period of 10 days. Women were excluded from the study to control for possible fluctuations in fluid balance resulting from menstrual cycles.
To assess the state of hydration, the researchers used a variety of well-established measures, including body mass and total body water, as well as blood and urine. The researchers found no significant differences in total body water or any of the measures of blood hydration status among those who drank coffee and those who drank water. Furthermore, no differences in urine volume or concentration between the two groups were observed.
"We found that moderate consumption of coffee, four cups a day caused no significant differences in a wide range of indicators of hydration compared to the consumption of equal amounts of water," said Sophie Killer.
Source: Revista Cafeicultura