Welcome to the wonderful world of herbalism. Plants make tons of beneficial (and to a lesser extent harmful) chemicals for animals like us. Plants can’t move so they use chemical to both deter and attract animals. Something like a fruit is supposed to be eaten which distributes the seeds so plants load them up on attractive chemicals (mostly sugars) so animals want to eat them. Since we all (plants and animals alike) share similar biochemistry it’s simple for plants to make hormones that we also use. Some of the presence is “intentional” and some is not.

To answer your question every fruit and vegetable has beneficial quantities similar to what you mentioned. The wider variety you eat the better.

The theory being that kiwi’s have serotonin and tart cherry juice has melatonin that help you sleep.

The serotonin in your kiwi gets mostly destroyed in you stomach acid. Any remaining amounts that do get absorbed into your bloodstream will never make it to your brain to do anything because of the blood-brain barrier. Only specific compounds can cross this. Your brain can only use serotonin that it synthesizes. Most of it sticks in your gut helping to regulate bowel movements.

It might be the antioxidants lowering inflammation, a hit of vitamin c or some sugar leaving you satisfied or placebo that helps.

Why do people make fun of “soy boys” because phytoestrogen, when dairy milk is literally mammal hormone soup?

All multi-cellular organisms use hormones and other chemicals to send signals between cells. Plants and animals inherited the same system—and many of the same molecular signals—but we adapt the specific purpose of each signal to whatever messages our bodies need to transmit.

It’s similar to how related languages can derive words from a common ancestor, but the meaning of the word in each language changes differently over time.

It’s weirder that every living thing on the planet’s DNA isn’t super different from anything else’s. We all share bits of DNA with other animals and even plants. Like humans share about 50% of the same dna as a banana.

It’s all just chemistry. Many compounds/molecules/whatever basically self-assemble and then from there the kinds of reactions are limited by chemistry.

From there evolution took over and found ways of doing things. Once it found those ways, it got past to everything that came after. Melatonin originally evolved in bacteria as an antioxidant.

From there it became useful for other things like regulating growth and as stress response as well as managing circadian rhythms and such like.

I’m not a scientist or qualified with any reliable technical knowledge about this, but I am aware that there’s a lot of plants that have chemicals in them that are identical to or closely related to the chemicals that are found in the human body.

I want to say that this is because we share some common chemistry with plants and that the mechanisms by which these hormones are created are some of the easier mechanisms for earth compatible biology to pull off.

After all, it does make sense that living creatures would adapt to eat foods that work with their bodies.

You’re talking about amino acids, which all life on earth possess compatible ones. Otherwise you wouldn’t be able to eat anything. Plants do not produce mammalian compatible hormones or we would have been extracting that shit for millennia to increase breast size, etc. The modern “Soyboy” shit was always made up.