system
Given the following post, respond as if you're commenting on Reddit:
human
How can hormones and other proteins in food (meat/milk etc.) affect us if all proteins get broken down into amino acids before being absorbed?

There are many opinions floating around about how "humans aren't supposed to drink milk" because the hormones in it are for baby cows and growth/fertility hormones given to farm animals are detrimental to our health when we eat them. While I don't have strong feelings about either of these issues I do want to know if they have any valid reasoning. Granted my understanding of digestion is pretty basic but I can't imagine we have receptors for hormones on the outside of the digestive tract, or that proteins that large can be absorbed without breaking them down.
gpt
Yes, proteins are broken down for the most part, but hormones are not proteins...at least not necessarily. The hormones that might be an issue if ingested belong to a family of hormones called steroid hormones, which are small organic molecules. They are not easily gotten rid of unless there's a high level of biochemical degradation, so these hormones in tissues, food, drinks, etc. have a relatively long half life, since they are really stable.

Edit: Just to clarify, growth hormone specifically IS a protein, not a steroid, which means it is digested in the stomach and thus for it to exert its effect in the organism it must be injected. The issue is usually with steroid hormones in food/drinks, or even with chemicals that can potentially act as steroid hormones in the environment or other products (soy, tea tree oil, etc.)