Although I no longer practice pharmacy in a traditional way, the information I learned years ago continues to be useful in my role as health educator. For example, a typical post-lecture Q and A session often yields a query about the potential for food to be drugs. Recently I was asked, "What's the most widely used food with drug-like action?" Without a second thought I replied, "Caffeine."
Each morning, worldwide, folks stumble out of bed and head straight for the coffee pot or pour a glass of their favorite cola beverage. Before the day ends more than 90 percent of us drink or eat the equivalent of two to three cups of caffeinated coffee. Four out of five Americans have two to four cups every day, while 25 percent qualify as true caffeine addicts by drinking more than five cups of coffee in a 24-hour period. Caffeine has been been added to more than 1,000 non-prescription medications including diet pills, stay-awake pills, cold tablets, and headache and allergy remedies.
Caffeine has been around a long time. Chinese literature dated 2700 BC talks about its effects. Chemically, it is one of a group of compounds called xanthenes, a mild central nervous stimulant. In addition to coffee and tea it's in cola beverages, chocolate, and many prescription and nonprescription medicines, especially analgesics and cold remedies.
It also doubles as a flavoring agent in baked goods, desserts, and puddings. The slightly bitter flavor is often used to balance the sweetness of the sugar in these products. In other words, unless you know what's in everything you put in your mouth, chances are you swallow some every day.
Your individual reaction to caffeine will be influenced by several factors including the amount you consume in relation to your body weight, your age, your emotional or nervous state, and your individual tolerance or "threshold." Once caffeine enters your blood it increases your heart rate, promotes secretion of stomach acid, speeds up urine production, dilates some blood vessels and constricts others. If you've ever experienced "coffee nerves" you know how caffeine can cause trembling, depression, diarrhea, loss of appetite, nervousness, and chronic muscle tension.
Because caffeine releases fatty acids into the blood stream, endurance athletes believe its ability to conserve glycogen (stored muscle fuel) can be used as a tool for improving performance—if they can manage its diuretic effects.
Despite a study that supported this glycogen-storing theory, most physiologists believe the effect of caffeine on athletic performance is psychological instead of physiological.
The relationship between caffeine and its impact on health and disease is variable. It's been praised as an adjunct to headache medications and for decreasing the wheeze of asthma by opening bronchial passages. It has been shown to be helpful in decreasing the risk of Parkinson's disease and gallstones.