A steaming mug of black tea on the desk may look harmless, yet researchers are mapping a more complicated health footprint. The brew’s caffeine can raise heart rate and blood pressure in sensitive drinkers, while chronic high intake is linked to palpitations and a heavier load on the cardiovascular system.
Teeth also pay a price. Dark pigments called tannins bind to dental enamel and build up as surface staining, especially when tea is sipped repeatedly across the day. At the same time, those same polyphenols that give black tea its bitterness can chelate non‑heme iron in the gut, forming complexes that are harder to absorb and lowering overall iron bioavailability.
Sleep is another casualty of this daily ritual. Caffeine blocks adenosine receptors in the brain, delaying sleep onset and fragmenting deep sleep architecture when tea is consumed late. Nutrition scientists caution that people with iron deficiency, pregnancy, or cardiovascular risk may need to time or limit black tea, treating it not as a neutral comfort drink but as a biologically active stimulant.
