Tejal SomvanshiHow you drink your tea may matter as much as how much of it you drink, according to a study published in the Journal of Internal Medicine. Drinking six to eight cups of unsweetened tea a day — particularly black tea — is associated with a 35% or greater reduction in vascular disease risk compared with non-tea drinkers. But drinking tea at very high temperatures is associated with a roughly 16% higher risk compared with non-drinkers.
Vascular disease covers conditions affecting the heart, arteries, and veins, including cardiovascular disease and stroke. They are among the leading causes of death in Australia, the US, and the UK. Research linking everyday dietary habits to vascular outcomes draws attention, and this study has done so because its findings run in two directions at once — tea is associated with benefit, but temperature is associated with harm.
The study population, as described in reporting by Bioengineer.org, appears to be Chinese adults, a group where high-volume tea consumption is deeply embedded in daily culture. The large pool of regular tea drinkers in that population allows for statistically strong analysis. Whether the findings translate directly to Western populations — who typically drink black tea with milk, which cools it substantially — has not been separately tested in this study, and the results should be understood in that context.
The researchers identify the protective mechanism as likely being the flavonoids in black tea — a type of polyphenol antioxidant linked in multiple prior studies to cardiovascular benefit. At six to eight cups daily, unsweetened, the cumulative flavonoid intake appears to produce a measurable association with lower vascular disease risk.
The inflammation problem with drinking tea too hot
The hot-tea finding works in the opposite direction. Drinking tea described as “burning hot” was associated with approximately 16% higher vascular disease risk compared with non-drinkers. The mechanism proposed by the researchers is chronic thermal injury — repeated burning of the oesophageal lining — which triggers systemic inflammation. That ongoing inflammation may contribute to vascular disease risk over time.
The study does not specify an exact temperature threshold at which tea becomes harmful. Available reporting describes the risk category as tea consumed immediately from boiling or very shortly after, before meaningful cooling has occurred. The finding should not be summarised as “tea above X degrees is dangerous” — no such temperature was identified in this study. The association is with habitually consuming tea at extreme heat.
For British and Australian tea drinkers, the habit of adding cold milk immediately drops the temperature substantially. The social norm in both countries is to drink tea cooled, and milk does that work automatically. The greater risk group described in this research is most likely those who consume tea the way it is common in parts of Asia, the Middle East, and North Africa: without milk, often freshly poured, and at large daily volumes.
Green tea and herbal infusions were not the primary focus of the protective association. The benefit was associated with unsweetened tea, with black tea most clearly featured. Adding sugar appears to reduce or negate the protective association.
The practical takeaway is accessible. If you already drink several cups of unsweetened tea a day, the study’s association data suggests it is good for your vascular health. If you drink it very hot, waiting a few minutes before consuming it is a sensible response to this research. The cooling window does not need to be long — just enough to move the tea out of the thermal-injury range.
Tea is among the cheapest widely available dietary habits, which makes its health associations broadly relevant regardless of household income. In Australia, vascular and cardiovascular disease sit alongside rapidly rising conditions such as dementia, which now accounts for more than 19,000 deaths annually (https://www.karmactive.com/dementia-19019-deaths-australia-asthma-decade-high-2025/), making affordable preventive habits politically and economically attractive. France’s own public health system has been under fiscal pressure this year, similarly pushing attention toward preventive health (https://www.karmactive.com/france-bond-yields-protests-limoges-fire-2026/). In regions where extreme weather has disrupted food supplies — as Cyclone Arnab did to parts of eastern India this week (https://www.karmactive.com/cyclone-arnab-andhra-pradesh-trains-cancelled-dead/) — locally grown tea remains a dietary staple for large populations where this research has immediate application.
