Caffeine's Effect on Platelets

According to CBS News, caffeine is America's fuel. More than 50 percent of Americans drink three to four cups of coffee a day, which works out to more than 330 million cups. But that's just coffee. If you include things like tea and caffeinated soft drinks, the number jumps to 80 percent of Americans drinking one form of caffeine or another. With all this caffeine consumption, it is important to understand what caffeine does to your body, including what it may do to the platelets in your blood.

Caffeine is a natural substance found in plants such as those that produce tea, coffee and cocoa. It is a diuretic and central nervous stimulant and is absorbed quickly into the brain. It has no nutritional value. Because caffeine is a central nervous stimulant, it can make you more alert and provide a temporary boost of energy. In small doses, such as two to four cups of coffee a day, caffeine is safe for most people; but too much caffeine produces symptoms such as restlessness, anxiety, irritability, headaches and abnormal heart rhythms. Caffeine is found in coffee, tea, soft drinks, chocolate and many medications.

Platelets are the smallest of the three types of blood cells: red blood cells, white blood cells and platelets. The normal platelet count in the body is between 150,000 and 350,000 per microliter of blood. Platelets are produced in the bone marrow. In a sense, they are your body's natural bandage. When you get an injury or a cut, the platelets come together to form a blood clot and stop the bleeding. If your platelet count is low, you are at greater risk of bleeding complications.

Researchers have looked for a possible connection between caffeine and platelets. A 2008 study published in "British Journal of Nutrition" looked at coffee and caffeine consumption and its effects on platelets. The study included 10 healthy subjects who consumed coffee during two sessions. Half drank 200 ml coffee, and the other half took a 180 mg caffeine capsule with 200 ml of water. While coffee had an anti-platelet effect, the platelets in the subjects who consumed only caffeine did not show any change. The study demonstrated that while coffee may affect the body's platelets by decreasing their ability to stick together, it is not the caffeine that is having this effect.

While caffeine in itself does not affect platelets, it can produce other side effects when consumed in large quantities. The American Medical Association Council on Scientific Affairs says moderate coffee and tea consumption is likely safe for most individuals but advises limiting consumption to three 8 oz. cups of coffee a day or five servings of caffeinated soft drinks or tea. If you have acid reflux, high blood pressure, chronic headaches or irregular heart rhythms, talk with your physician regarding your caffeine intake.