> Food allergies are the result of our immune system mistaking something harmless for a severe threat. If you IDS has never seen X and X is unlike anything it has seen, it will probably flag it. > There had been long-standing advice to avoid foods that can trigger allergies during early childhood. At one point, families were once told to avoid peanut until their child was three years old. This advice was never based…
It's a whole lost more complicated than this, see for example antigens https://en.wikipedia.org/wiki/Antigen and epitopes https://en.wikipedia.org/wiki/Epitope