I know that food proteins in our digestive system are denaturated and broken down into amino acids or very small peptides that are then absorbed in the small intestine. If some proteins stay undigested they move to the large intestine and either gut flora eats them or they are excreted.
But lately, I've been hearing a lot of stuff like "if you eat a lot of eggs there will be egg proteins in your blood" or "drink liquid collagen and it will travel to your skin through the blood". It seems really stupid to me. I imagine if all sorts of food proteins entered our blood they would wreak havoc there catalyzing random reactions, triggering immune responses, etc. So it cannot be a very frequent event. But I've been wondering if some of the food proteins can on occasion end up in the blood of relatively healthy people. Does this ever happen? With food allergens maybe?