Caffeine (cont.)

Author:
Medical Editor:

Is caffeine a diuretic?

Caffeine has been considered a diuretic by experts and consumers for years. Some people believe that drinking caffeinated beverages will cause them to lose fluids so they can't be counted as part of their daily intake. Others say that caffeinated beverages do not increase fluid losses. The best way to flush out the truth is to examine the research.

Each day our body has a need for water. We lose water through respiration, skin, renal, and gastrointestinal tract losses. Our intake of water comes from liquids and foods. We need to maintain an adequate water balance for our bodies to function properly. Factors such as age, activity level, health, diet, and environment can affect our water balance.

Some research has shown that caffeine intake can also affect our fluid balance. In one study, 12 caffeine consumers were told to abstain from caffeine for five days and were then given 642 mg of caffeine in the form of coffee. Their urine output increased when given the caffeine. Another study done on eight men tested the effect of 45 mg, 90 mg, 180 mg, or 360 mg of caffeine on urine volume. An increase in urine volume was seen only at the 360 mg dose of caffeine. One limitation to these studies is that they did not evaluate the impact of caffeine when consumed on a regular basis. A onetime dose may affect the body differently than daily consumption.

Back in 1928, caffeine was shown to have no significant impact on urinary output. Subsequent studies have shown that caffeine-containing beverages did not impact urinary output any differently than other beverages. Based on this, the Institute of Medicine recommends that "unless additional evidence becomes available indicating cumulative total water deficits in individuals with habitual intakes of significant amounts of caffeine, caffeinated beverages appear to contribute to the daily total water intake similar to that contributed by noncaffeinated beverages."

This doesn't mean that caffeine does not increase your need to urinate. Your reaction can depend on the amount that you consume, the type of product, and your tolerance level. If you have urinary incontinence, you may experience a greater "urgency" to urinate after consuming a caffeinated beverage. You will need to monitor your reaction and tolerance to caffeine to determine how you are affected. Water is still the recommended choice for optimal hydration, so be sure to include it as part of your daily fluid consumption.

Medically Reviewed by a Doctor on 12/10/2013