The question of whether mixing black tea with milk produces substances that hinder digestion is somewhat controversial. Here are the scientific perspectives:

Interaction Between Tannins and Proteins Black tea contains tannins, while milk contains proteins. Some believe that the combination may form tannin-protein complexes that are harder to digest. These complexes might slow digestion in the gastrointestinal tract and affect nutrient absorption. However, the impact is generally minimal and varies among individuals.

Calcium Absorption Concerns Another perspective suggests that oxalates in black tea could bind with calcium in milk to form calcium oxalate, which might reduce calcium absorption. Nevertheless, this effect is usually insignificant, as milk itself is a rich calcium source, and the overall loss of calcium is negligible.

Minimal Real-World Impact From a dietary perspective, combining tea with milk in moderate amounts does not pose significant health risks. Popular beverages like English tea with milk have a long history of consumption, with no substantial evidence indicating serious health concerns from this combination.

So drinking black tea with milk in moderation is safe for most people, and there’s no need to worry about potential adverse effects. If you have digestive issues or lactose intolerance, you may adjust your dietary choices accordingly. For further concerns, consulting a nutritionist or healthcare professional is recommended.