Caffeine, Coffee, and Your Health

Diabetes is the seventh leading cause of death in the United States. An inverse relationship was found between coffee consumption and diabetes-related mortality (Loftfield et al., 2015). Wolde, 2014, found that a higher intake of coffee is associated with a significantly lower risk of diabetes, while tea, which also contains caffeine, has no effect on diabetes risk. In fact, those who consumed 6 or more cups of coffee per day have a 35% lower risk of diabetes than those who drink 2 cups or less per day (Wolde, 2014). Using data from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial, the association between coffee consumption and mortality was looked at, as were disease specific associations. The study looked at the amount of coffee consumed (no coffee, <1 cup per day, 1 cup per day, 2-3 cups per day, 4-5 cups per day, ≥6 cups per day), as well as type of coffee (caffeinated and decaffeinated). The inverse association between overall mortality and coffee consumption is thought to be due to the inverse associations between coffee consumption and other conditions including heart disease, chronic lower respiratory disease, influenza/pneumonia, and intentional self-harm (Loftfield et al., 2015). In 2013, Jiang et al. conducted a meta-analysis of 31 prospective studies to look at the associations between coffee/caffeine intake and the risk of T2DM. In all 31 studies, the inverse relationship of greater coffee consumption and lower diabetes risk was found, some with greater significance than others.

Although the exact mechanisms as to why coffee aids in lowering the risk of developing diabetes are not completely understood, multiple inferences have been made (Loftfield et al., 2015). Caffeinated coffee was found to be positively related to improved insulin sensitivity, while decaffeinated coffee has a positive relation to beta-cell function (Jiang et al., 2013). Caffeine may also protect against T2DM through an increase in metabolic rate and thermogenesis, which stimulates fatty acid release and fatty acid oxidation, thus mobilizing glycogen in the muscles (Jiang et al., 2013).

Other factors influence the extent to which caffeine consumption impacts the risk of diabetes. Studies that included gender found that although both genders had inverse relationships between coffee consumption and diabetes, this association was higher in females. Body Mass Index (BMI) plays an important role in determining how strong coffee’s effects are since higher BMI’s can cancel out those benefits. Adverse outcomes from smoking may also cancel out the positives of caffeine intake, as stronger associations were found among non-smokers. Experiments have been conducted to show that smokers eliminate caffeine from the body more quickly than non-smokers, thus limiting the time they have to utilize the benefits of caffeine (Jiang et al., 2013).

There is currently no recommendation as to how much coffee is needed to reap the protective behaviors against diabetes. However, research shows that an intake of 4 cups of coffee per day or more has significantly greater benefits than 2 cups per day when it comes to lowering the risk of diabetes (Wolde, 2014).