The Star"buck"s Stops Here: What is the Role of Coffee/Caffeine on Long-Term Health?

            The market for coffee sales in the United States alone is $18 billion, owing to the fact that over 50% of Americans drink coffee daily, and the average coffee drinker consumes 3.1 cups of coffee per day.  Coffee consumption has sharply increased worldwide over the past several decades (Figure 1), although it has surprisingly decreased dramatically in the United States (Figure 2). 

Figure 1: Worldwide coffee consumption in weight by decade (www.unctad.info) .

Figure 2: Volume of coffee consumption in the United States by year www.marketwatch.com) .

            With so much recent focus on trendy nutritional regimens and the popularity of “chemical”-free diets such as gluten-free and organic, it is surprising that there has not been a greater public interest in the health effects of coffee.  Should we be drinking more, or drinking less? Fortunately, several studies have been performed assessing the association between coffee consumption and mortality.  While all of these studies exhibit the caveat of only evaluating correlations and not causal relationships, meaning that some other associated variable may actually be responsible for the observed effects (known as a cofactor), they can still provide useful information.