Medical professionals have commonly warned against the dehydrating effects of alcohol and caffeine in the body. As of 2010, authorities such as Harvard Medical School and Vanderbilt University continue to advance the dehydrating effects of both. But recent studies question whether drinks containing caffeine decrease hydration in the body the way alcohol does. Researchers no longer list the effects of both caffeine and alcohol on hydration in the body negatively.
Caffeine and Hydration Levels
Hydration levels in the body of varying percentages of caffeinated and non-caffeinated drinks show no significant difference. A 2000 study at the University of Nebraska Medical Center comparing hydration levels indicated mixing water, caffeinated drinks and non-caffeinated drinks resulted in the same amount of hydration for study participants. Those conducting the research decided there was no measurable difference between the various drinks as long as the overall volume stayed the same.
Caffeine and Re-hydration After Exercise
Substituting caffeinated drinks for water causes no hydration level difference with physical exercise. In a 2005 study by the University of Connecticut, Human Performance Laboratory, no differences in fluid-electrolyte balance or renal function for adult males showed up for participants. Researchers stated that the belief that caffeine represents a diuretic contributing to accelerated dehydration levels in the body wasn't supported by the study.
Alcohol Triggers Dehydration
As opposed to the studies on caffeine and dehydration of the body, alcohol acts as a diuretic and dehydrates the body. Athletes exercised and re-hydrated with varying amounts of alcohol in their drinks in a report by Peak Performance. They reported the amount of water lost in urination correlated with the percentage of alcohol contained in the drink. The more alcohol contained in a drink, the less water an athlete was able to maintain.
The Diuretic Alcohol
Drinking alcohol causes the body to lose water through urination. Alcohol decreases the anti-diuretic hormone vasopressin, which acts on the kidneys to reabsorb water and salt into the body. Water excreted through urination lowers the hydration levels in your body. Alcohol-induced dehydration also causes a loss of needed nutrients and minerals, such as magnesium, potassium, calcium and zinc, according to Peak Performance.
References
- Journal of the American College of Nutrition: The Effect of Caffeinated, Non-Caffeinated, Caloric and Non-Caloric Beverages on Hydration
- Peak Performance: Caffeine dehydration
- National Institutes of Health: Caffeine
- Vanderbilt University: Drinking Eight Glasses of Water a Day
- Harvard University Medical School: Air Travel Health
