Many people can, but not because yogurt is low in lactose. It grades high, like milk. What helps is that the bacterial cultures bring lactase with them and keep working in your gut, so the same amount of sugar is digested more completely and more slowly than it would be from a glass of milk. In practice that means starting with a few spoonfuls of plain, live-culture yogurt with a meal, and treating a large bowl as a real lactose load rather than a free pass.

It grades borderline, which puts it above fresh milk and well below aged cheese or kefir. Histamine is produced by the cultures during fermentation and keeps accumulating afterwards, so a short-fermented plain yogurt eaten well inside its date is the lower-histamine option and a pot that has been open in the fridge for a week is not. If yogurt gives you flushing, headache or a stuffy nose rather than bloating, histamine is the likelier explanation.

Because fermentation adds triggers that fresh milk does not have. Yogurt picks up borderline histamine and tyramine, and it grades badly for SIBO, so someone whose problem is bacterial overgrowth or histamine rather than lactose can react to yogurt while drinking milk quite happily. The reverse pattern, fine with yogurt and not with milk, usually points to lactose and the cultures helping you digest it.

On the dairy triggers, clearly yes. Coconut and almond yogurts grade clean for lactose and for dairy protein, which removes both halves of the milk problem at once. They are still fermented, so histamine stays borderline and tyramine is not zero, and many of them add inulin or chicory root fibre for texture, which is a FODMAP in its own right. Read the ingredients rather than the front of the pot.