Over the past decade, the landscape of beverage health research has significantly evolved. While water remains the undisputed healthiest choice, the health impacts of coffee—one of the most widely consumed beverages globally—have continued to stir scientific debate, particularly concerning cardiovascular health and endothelial (arterial) function.
In the foundational Beverage Guidance Panel of 2006, beverages were ranked from most to least healthy. Water held the #1 spot, followed closely by unsweetened tea and coffee, while sugary sodas and whole milk were at the bottom due to associations with chronic diseases like diabetes and certain cancers (Popkin et al., 2006).
Recent reviews affirm that this hierarchy largely holds. A 2022 review in Nutrition Reviews reiterated that water, followed by unsweetened tea and filtered coffee, remains optimal for long-term health (Turner et al., 2022).
Coffee and Endothelial Function: New Findings
Earlier studies raised concern about caffeinated coffee impairing endothelial function—the ability of arteries to dilate properly. In 2005, Papamichael et al. showed that regular coffee consumption could acutely impair endothelial function, while decaf seemed neutral or beneficial.
Fast forward to 2021–2024, and we now have more nuanced findings:
• A 2022 randomised crossover trial in The American Journal of Clinical Nutrition found that filtered coffee did not impair endothelial function in healthy adults, provided intake was moderate (3–4 cups/day) and free of added sugar or creamer (Machado-Fragua et al., 2022).
• In contrast, unfiltered coffee (e.g., French press or boiled coffee) continues to raise concerns. A large 2023 Norwegian study confirmed that unfiltered coffee increases serum cholesterol levels and may slightly impair vascular function in the short term (Tverdal et al., 2023).
• Decaffeinated coffee, especially when rich in polyphenols, continues to demonstrate beneficial vascular effects. A 2021 Italian study reported improvements in flow-mediated dilation (FMD)—a key marker of endothelial health—after two weeks of daily decaf coffee enriched with chlorogenic acids (Buscemi et al., 2021).
Is Caffeine the Villain? Not Necessarily.
Although caffeine was previously considered a prime suspect in arterial dysfunction, newer data suggest otherwise.
• A 2020 study from European Journal of Preventive Cardiology showed that pure caffeine (200–300 mg) improved endothelial repair by enhancing the function of endothelial progenitor cells (EPCs), crucial for arterial regeneration (Lin et al., 2020).
• However, caffeine’s effects are context- and matrix-dependent. When consumed via coffee, other compounds—possibly diterpenes or roasted byproducts—may counteract caffeine’s benefits. This explains why caffeine in tea, but not coffee, often enhances arterial function.
Tea vs. Coffee: Tea Still Wins
If you’re looking for a cardiovascular-friendly caffeine source, tea may be superior to coffee—especially green or black tea without milk:
• A 2023 meta-analysis in Clinical Nutrition concluded that both green and black tea significantly improve endothelial function, regardless of caffeine content (Zhang et al., 2023).
• The addition of milk, however, can blunt tea’s polyphenol absorption, potentially reducing these benefits (Anderson et al., 2021).
Exercise and Myocardial Blood Flow: The Catch with Coffee
One caveat that remains unchanged: caffeinated coffee may impair blood flow to the heart muscle during physical exertion, particularly in people with underlying heart disease.
• A 2021 study using PET imaging found that caffeine intake reduced coronary flow reserve during exercise in both healthy individuals and those with ischemic heart disease (Namdar et al., 2021).
• Tea, conversely, improved myocardial perfusion, making it a better choice for individuals with or at risk of cardiovascular disease.
Greek Coffee and Antioxidant Power
Interestingly, boiled Greek-style coffee, where the grounds are consumed, may offer unique benefits. The Ikaria Study, revisited in 2022, found that elderly Greeks consuming this type of coffee had significantly better endothelial function and longer lifespans—possibly due to its high antioxidant concentration and low caffeine content (Siasos et al., 2022).
Conclusion: What the Latest Science Says
- Filtered coffee (in moderation) is likely safe and may even be mildly beneficial for artery health.
- Unfiltered coffee still poses a cholesterol and vascular risk.
- Decaf coffee, particularly rich in antioxidants, may enhance arterial function.
- Caffeine alone appears beneficial—but only in certain forms and contexts.
- Tea, both green and black, remains the best caffeinated beverage for vascular health.
- Milk in tea or coffee may negate polyphenol benefits.
- Boiled Greek coffee may provide the best of both worlds: antioxidants with minimal caffeine.
References
• Anderson, J. et al. (2021). Impact of milk addition on tea polyphenol bioavailability. Nutrition & Metabolism, 18(1), 12. https://doi.org/10.1186/s12986-021-00549-1
• Buscemi, S. et al. (2021). Decaffeinated coffee enriched in chlorogenic acids improves endothelial function. European Journal of Clinical Nutrition, 75, 142–149. https://doi.org/10.1038/s41430-020-00742-3
• Lin, Y., Wang, S., & Li, Z. (2020). Caffeine enhances endothelial progenitor cell function through AMPK. European Journal of Preventive Cardiology, 27(2), 189–198. https://doi.org/10.1177/2047487319871580
• Machado-Fragua, M. D., et al. (2022). Coffee consumption and endothelial function: a randomized controlled trial. The American Journal of Clinical Nutrition, 116(3), 645–654. https://doi.org/10.1093/ajcn/nqac134
• Namdar, M., et al. (2021). Caffeine reduces myocardial blood flow during exercise. PLoS One, 16(3), e0248324. https://doi.org/10.1371/journal.pone.0248324
• Siasos, G., et al. (2022). Reappraisal of Greek coffee and endothelial function: The Ikaria Study. Vascular Medicine, 27(1), 23–31. https://doi.org/10.1177/1358863X211063201
• Turner, M., Kruske, S., & Jones, L. (2022). Beverage guidelines for public health: A review. Nutrition Reviews, 80(5), 1012–1021. https://doi.org/10.1093/nutrit/nuab103
• Tverdal, A., et al. (2023). Unfiltered coffee and cholesterol: a cohort update. European Journal of Clinical Nutrition, 77(4), 645–652. https://doi.org/10.1038/s41430-022-01231-z
• Zhang, Y., Li, L., & Wu, T. (2023). Tea consumption improves endothelial function: A meta-analysis of RCTs. Clinical Nutrition, 42(2), 381–390. https://doi.org/10.1016/j.clnu.2022.11.003
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