4. Food Standards Agency - Eat well, be well - Food allergy and intolerance

Food Standards Agency - Eat well, be well - Food allergy and intolerance: "Food allergy and food intolerance are both types of food sensitivity. When someone has a food allergy, their immune system reacts to a particular food as if it isn't safe. If someone has a severe food allergy, this can cause a life-threatening reaction.

Food intolerance doesn't involve the immune system and is generally not life-threatening. But if someone eats a food they are intolerant to, this could make them feel ill or affect their long-term health."

The Food Standards Agency is a wealth of food health information that I often refer to.