Response to Letters Regarding Article, “Association of Coffee Consumption With Total and Cause-Specific Mortality in 3 Large Prospective Cohorts”

We appreciate Henri-Jean’s comments on our prospective cohort study on coffee consumption with total and cause-specific mortality ¹. Henri-Jean pointed out that unfiltered coffee consumption increased LDL-cholesterol and triglyceride concentration, and filtered coffee consumption did not significantly change LDL-cholesterol or triglyceride concentrations. Therefore, it was suggested that individuals are encouraged to continue or even increase their coffee consumption might not be applicable to unfiltered coffee drinkers, i.e., coffee made by capsule coffee machines.

We agree with Henri-Jean that unfiltered coffee consumption increases LDL-cholesterol and triglyceride concentration ², and filtered coffee consumption does not. The lipid-increasing effects of unfiltered coffee are due to cholesterol-raising compounds such as Cafestol and Kahweol ³. However, the unfiltered coffee used in randomized trials (RCT) was mainly boiled coffee ^{2, 4}. As the amount of Cafestol and Kahweol in espresso is different from that in boiled coffee ³, whether espresso increases blood lipid concentration as boiled coffee is unknown. In our study, we did not ask about coffee preparation method. However, most of the coffee consumed in the U.S. is filtered coffee. Our observation that coffee consumption was associated with lower risk of total mortality and mortality due to cardiovascular disease (CVD) is consistent with previous studies on blood lipids and incidence of CVD ^2,3. Even if a small proportion of participants consumed boiled coffee in our cohorts, because coffee contains numerous compounds including chlorogenic acid, lignans, quinides, trigonelline, and magnesium, which might reduce insulin resistance and systematic inflammation, ⁵.the net effects of consuming such coffee on CVD are uncertain and need to be examined in future studies. Overall, our results support the recommendation by the 2015–2020 Dietary Guidelines for Americans that moderate coffee consumption can be included as part of a healthy diet and lifestyle.