Doctors of USC

Good news for coffee junkies: that hot, black brew habit you've been indulging may put a dent in your pocketbook, but, in moderate amounts, probably won't damage your overall health.

The most recent studies have found no relationship between moderate coffee intake and the risk of any type of cancer, according to the American Cancer Society. Studies also dispute previous contentions that caffeine-the stimulant in coffee and other products like colas and chocolate-decreases fertility, increases osteoporosis, causes birth defects or cardiovascular disease. In fact, unlike "addicting" substances, the body does not build a tolerance to caffeine and so does not require ever increasing amounts to feel the stimulant effect. One recent study also showed that those who drink coffee may be at reduced risk for Parkinson's disease.

Not that caffeine is risk-free. Even though it may be seen as a "natural" substance because it is found in some 60 plants, some studies link caffeine with worsening fibrocystic breast disease in women prone to the condition. Pregnant women are advised to reduce their caffeine intake.

Caffeine affects people differently, causing nervousness, jitters and insomnia in those who have a low tolerance. The acidity in coffee can worsen such conditions as gastro-reflux disease, or heartburn. For some, cutting back abruptly on regular allotments of coffee or caffeine-containing products can cause irritability and headaches. "Caffeine may have some effect on blood pressure as well," notes Howard Hodis, M.D., associate professor of medicine and director of USC's Atherosclerosis Research Unit.

Hodis also notes that "the amount of caffeine in coffee is variable depending on how the coffee is prepared-for example, drip preparation has a higher caffeine content than brewed. Also, the dosage of caffeine is more concentrated in espresso, even though the serving size of espresso is generally smaller." Hodis and others recommend moderation when it comes to coffee.