Caffeine influences your digestive system in multiple ways. It serves as a diuretic, it quickens the digestive process and it stimulates your colon. The effect of these mechanisms varies based on other physical factors; depending on your situation, caffeine can actually cause, relieve, worsen or prevent constipation. If you understand how the process works, you can avoid the uncomfortable effects of caffeine and even use its gastrointestinal powers to your advantage.
Caffeine’s Diuretic Effects
As a diuretic, caffeine affects both your kidneys and colon. Primarily, it causes the liquid you ingest to pass through your body more quickly than it otherwise would. Your kidneys function by removing extra liquid from your blood, processing it and then excreting it as urine. When caffeine enters this system, it makes you urinate more than usual, meaning that less water reaches your colon. The colon, a 5-foot-long segment at the end of your gastrointestinal tract, moves your body's solid waste from your small intestine to your rectum. Processing this waste involves absorbing some excess fluid, otherwise, the stools would always tend toward diarrhea. Caffeine, however, can make your colon absorb too much fluid, too quickly.
Dehydration and Constipation
The dehydrating effects of a diuretic, like caffeine, can cause constipation in two ways. First, if your kidneys remove too much water from your system, through frequent urination, then your colon may not receive enough fluid to process the stools properly. Second, the colon's overactive absorption of liquid also takes away the moisture needed to make your bowel movements soft, smooth and easy to pass. The dry, hardened stools that result from dehydration cause constipation. Because of their stiffness, your colon struggles to move them along and excrete them from your body. In this manner, caffeine can either cause constipation or worsen existing conditions.
Colonic Movement and Constipation
In some situations, caffeine can actually relieve or prevent constipation. In addition to acting as a diuretic, caffeine also triggers the contraction of your colon. Through repeated contractions, your colon regularly moves waste through its 5 feet of tubing. Because hardened stools don't move along easily, constipation can slow this process. By causing colon contractions, caffeine can help stimulate and revive this process. Additionally, because caffeine speeds up the movement of fluids through your digestive system, it can more swiftly direct water to your too-dry colon. If you get your caffeine through coffee, you may experience an additional benefit; the warm temperature of the coffee may also help soften painfully hardened feces.
If you abstain from consuming caffeine, of course, then the caffeine has no opportunity to cause constipation. If you do consume caffeine, however, you can still compensate for its diuretic effects and hence prevent the dehydration that leads to constipation. By drinking plenty of non-caffeinated fluids, preferably water, you can ensure that your colon always has enough liquid to keep your stools moist and to process your solid wastes effectively. If you remain properly hydrated, then caffeine will only serve as an aid and stimulant to your digestion, without causing constipation.