A new review of data from more than 650,000 people found that low-to-moderate daily coffee drinking is linked to a modestly lower risk of heart failure.
Moderately great news, right? But there is a catch: The researchers themselves described the evidence as “low certainty.”
The study, published March 17 in the Journal of Health, Population and Nutrition, pooled results from 13 long-term studies tracking 656,666 participants and more than 20,000 heart failure cases. The researchers framed the study as an update to the only dedicated meta-analysis on coffee and heart failure risk, which came in 2012.
Across seven independent cohorts, moderate coffee drinkers — described as 2 to 4 cups a day — had a roughly 7% to 8% lower risk of heart failure compared to the reference group.
The data traced what researchers call a J-shaped curve, with the benefit appearing strongest at low-to-moderate intake, then leveling off.
The clearest finding came at 1 to 2 cups per day, where the association was a roughly 12% lower risk, with notably consistent results across studies. At 5 or more cups daily, the apparent benefit faded and the results became much more variable.
The authors also reported that, within cohorts that separated coffee types, caffeinated and decaffeinated patterns looked broadly similar, suggesting caffeine alone is unlikely to be the whole story.
All 13 studies in the analysis were observational, meaning researchers tracked what people already did rather than assigning coffee intake, making it hard to rule out confounding factors.
Additionally, the new study combines data that define “cup” differently or not at all — while also relying on self-reporting habits — which can blur dose comparisons.
The researchers — who were affiliated with Ivano-Frankivsk National Medical University in Ukraine, NMC Specialty Hospital in Abu Dhabi and Sudan University of Science and Technology — did not declare any competing interests or private funding behind the meta-analysis.
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