The immune system is, and probably always will be, a hot health topic. This should come as no surprise: it is, after all, our body’s first line of defence against illness.

In theory, a robust immune system should protect us from the debilitating effects of the cold and other seasonal allergies, as well as more crippling chronic ailments.

Of course, not everyone can rely on such a health-sustaining system – and even the strongest immune defences need a boost once in a while.