The Effects of Caffeine on Dehydration

Used by millions of people worldwide as a stimulant, caffeine is provided in a wide variety of drinks, including coffee, tea, sodas and sports drinks. It can be found in chocolate and even in pill format. There are numerous conflicting studies about caffeine, attesting to both its benefits as well its negative affects on the body.

Dehydration

• Caffeine increases the blood flow to the kidneys and leads to a slight reduction in the re-absorption of sodium. It is widely believed that caffeine is a diuretic and directly linked to increased dehydration. However, numerous studies can be found that either support or disprove these claims. Because caffeine is most often provided in liquid form, the consumption of additional liquid will increase the frequency of urination. If a person is urinating more frequently yet has not replenished these fluids, he may become increasingly dehydrated. This is true of any liquid and is not a testament to the diuretic properties of caffeine.

Arguments, Tests and Studies

• Dehydration is a difficult symptom to monitor. The normal duration of dehydration is is not clear, and it is difficult to measure what would be considered an “increase” in dehydration. Other arguments and factors widen the test parameters. For example, although caffeine is usually combined with other ingredients, some argue that other chemicals such as artificial sweeteners are the true "dehydration causing culprits."

The conclusion

• There is evidence that caffeine can affect the kidneys in a way that may lead to dehydration. However, this evidence is not nearly as substantial or conclusive as one would think in light of the widely spread claims and beliefs.