Why brightly coloured plants are healthy to eat

"Can you explain why bright plants of primary colours, such as red, orange, yellow and green have potent health benefits for those who eat them but there are not similar benefits from eating plants that are blue, black or brown?"

Why are bright colours health-promoting?

This is the question I posed for Quantum Biologist, Keryn Johnson, to answer. To put it mildly, Keryn did a deep dive in answering my question!

Here is his answer, just to strain your brain:

https://www.ohbeehave.co.nz/blogs/news/answering-garys-question