The relationship between coffee drinking and heart disease has been investigated in numerous studies but strong, independent risks associated with coffee drinking have not been clearly documented. Researchers at Johns Hopkins Medical Institute recently found heavy coffee drinkers (defined as five or more cups per day) were two to three times more likely to have coronary heart disease than were nondrinkers (NEJM, October 16, 1986). This relationship was true even when accounting for other important risk factors such as age, smoking habits, serum cholesterol and blood pressure.
However, the study did not control for the effects of diet, sedentary lifestyle or high levels of occupational stress. Nor did it indicate the exact quantity in ounces of coffee consumed, the type of coffee (regular or decaffeinated), the brewing method, or the use of cream or sugar.
If coffee drinking does increase the risk of heart disease, it may do so through its effect on cholesterol. A few studies have linked heavy coffee consumption to elevated total serum cholesterol, although caffeine alone does not seem to be responsible. Perhaps it’s not even the coffee, but a high saturated fat diet among heavy coffee drinkers that’s increasing the risk of heart disease. Increased coffee consumption by men has been associated with increased calorie consumption from fat and increased cholesterol intake.(Adapted from DNS ALERT, Cornell Cooperative Extension, Dec. 1986)
Is it true that coffee drinking can cause cancer?
Earlier research studies suggested a link between coffee consumption and lower urinary tract cancer, renal (kidney) cancer, and pancreatic cancer, causing widespread concern among coffee drinkers. However, follow-up research has revealed a number of inconsistencies and serious design flaws in these studies. Several, for instance, did not control for the variable of smoking, which has causative links to many types of cancer. As it stands now, no clear evidence links coffee consumption to any type of cancer according to current western medicine research.