Is coffee good or bad for your heart?
For most healthy adults, three to four filtered cups per day are associated with a beneficial effect on the heart and blood vessels. Pregnant women are an important exception: for them, the maximum is one to two cups per day.
Three to four cups per day are associated with roughly 15% lower odds of cardiovascular disease and around 19% lower odds of dying from it. Overall mortality is also approximately 17% lower in moderate coffee drinkers. This applies to both regular and decaffeinated coffee1,2,3,4,5.
These are associations, not proven causation. Moderate coffee drinkers may also lead healthier lives in other respects. Mendelian randomisation, an approach that is better able to distinguish causation, supports a protective effect for diabetes and chronic kidney disease. For other cardiovascular outcomes, that evidence is less convincing2,3.
The picture for blood pressure is nuanced. One cup can briefly and mildly raise blood pressure, but regular coffee consumption does not lead to chronically elevated blood pressure, even at up to 600 mg of caffeine per day4,5,6. The risk of most heart rhythm disorders does not appear to be increased. Coffee can trigger extra harmless heartbeats. The evidence on atrial fibrillation remains unclear4,5,6.
The brewing method makes a concrete difference. Unfiltered coffee, such as that from a cafetiere, raises LDL cholesterol (the 'bad' cholesterol). Filtered coffee has little to no such effect4. Too much coffee can cause anxiety and sleep problems. At extremely high doses there is a risk of toxicity, and women who consume large amounts also face an increased risk of bone fractures7,3,6,1.
Pregnant women form a distinct risk group. High consumption is associated with a 31% greater chance of low birth weight, up to 22% greater chance of preterm birth, and a 46% greater chance of pregnancy loss. Guidelines advise pregnant women to consume no more than 200 mg of caffeine per day, which corresponds to one to two cups1,3. The most favourable association for overall health is seen at one to five cups per day.
The claims are based on several large observational studies and meta-analyses (PMID 29167102, 32706535, 40806142, 40626862, 38963648, 28756014, 26074744). Randomised controlled trials examining hard cardiovascular endpoints are largely absent, which limits causal interpretation.