The Evidence:
Crippa, A., Discacciati, A., Larsson, S. C., Wolk, A., & Orsini, N. (2014). Coffee consumption and mortality from all causes, cardiovascular disease, and cancer: A dose-response meta-analysis. American Journal of Epidemiology, 180, 763-775. doi: 10.1093/aje/kwu194
What did the meta-analysis look into?
The meta-analysis investigated whether drinking coffee is related to disease and death from ‘any cause’, death from cardiovascular disease (CVD), and death from cancer. The study compared people that regularly drunk coffee to those that rarely or never drank coffee, with a focus on the dose consumed. The following questions were answered:
(1) Is drinking more coffee associated with greater risks and death?
(2) What dose of coffee might be good or bad for health?
The meta-analysis synthesized evidence from 21 studies, including a total of 121,915 deaths and 997,464 people from the United States, Europe, and Japan, who were followed between 7.7 years and 24 years.
What did the evidence suggest about the relationship between coffee consumption and death from ‘any cause’?
The association between coffee and all-cause mortality was ‘non-linear’, which, essentially, means a “predictable but complicated” relationship. Specifically:
Drinking 1 cup of coffee per day was associated with the highest risk of all-cause mortality.
Drinking 4 cups a day were associated with the lowest risk of all-cause mortality (16% risk reduction).
What did the evidence suggest about the relationship between coffee consumption and death from CVD?
The association between coffee and CVD mortality was also found to be ‘non-linear’.
Specifically:
Drinking 6 cups of coffee per day was associated with the highest risk of dying from CVD.
Drinking 3 cups of coffee per day was associated with the lowest risk of dying from CVD (21% risk reduction).
What did the evidence suggest about the relationship between coffee consumption and death from cancer?
The association between coffee consumption and cancer mortality was not statistically significant, which means that there was “little if any credible evidence” for said association.
The take-home message
Compared to people that rarely (or never) drink coffee, those who drink 3-4 cups of coffee per day are likely to reduce their risk of dying from “any cause”, including from cardiovascular disease. Also, coffee consumption does not appear to be related to cancer mortality. The reasons why 3-4 cups per day may be protective to health are not extremely clear but could be due to anti-oxidant and anti-inflammatory coffee compounds. Broadly speaking, regular and long-term consumption of 3-4 cups of coffee offers noteworthy health protective benefits (but consumption of < 3 cups or >5 cups does not). Coffee is often being considered as potentially unhealthy but this has not been supported by meta-analytic studies.
