Reevaluating the “Tea-Heart Health” Connection: What the Latest Science Actually Shows

 

Over recent months, a claim has been circulating that drinking tea and coffee can protect you from high blood pressure and heart disease — and that adding milk somehow undermines this benefit. At first glance, this sounds compelling: plant compounds called polyphenols are often touted as “heart-healthy,” and tea and coffee are two of the most commonly consumed sources worldwide.

But what does rigorous science actually say?

A large new analysis published in BMC Medicine followed more than 3,100 British adults for over a decade to examine how long-term intake of polyphenol-rich foods and beverages affects cardiovascular risk scores. The researchers created a dietary scoring system that captured habitual consumption of key polyphenol sources — from tea and coffee to berries, whole grains, nuts, and olive oil. Those with higher scores tended to have lower predicted cardiovascular disease risk, lower diastolic blood pressure, and higher HDL cholesterol, a favorable lipid marker. 

Importantly, this kind of research shows association, not direct causation. That means we cannot claim that tea or coffee alone prevents heart disease. Rather, higher intake of polyphenol-rich foods — in the context of overall healthy dietary patterns — correlates with improved cardiovascular risk profiles.

Mechanistically, polyphenols such as flavonoids and phenolic acids have been linked to improved vascular function and antioxidant effects in controlled experiments. They appear to support nitric oxide pathways in blood vessel walls, reduce oxidative stress, and modulate inflammation — all relevant for vascular health. 

The idea that adding milk to tea or coffee eliminates benefits comes from preliminary absorption studies suggesting proteins can bind some polyphenols during digestion. These effects have not been shown in large human cardiovascular outcomes, and many observational studies include mixed-milk beverages without loss of association. So it’s premature to assert that milk negates any benefit.

In short, the credible takeaway is this: a dietary pattern rich in plant-derived polyphenols — including tea and coffee — supports cardiovascular health markers when combined with overall healthy lifestyle habits. But no individual food or beverage acts in isolation, and current evidence does not support claims of absolute protection or universal effect sizes.

Always interpret nutrition research carefully — correlation is not causation, and complex human physiology rarely yields simple one-size-fits-all answers.