Tangential to this topic, but Isaac Asimov wrote a book called "The Chemicals of Life" in 1954, just after Watson and Crick identified the double-helix structure of DNA. Many people don't know this, but Asimov was, at one point, a professor of Biochemistry at Boston University.
The book provides a high-level overview of the biological functions of the body and why we need certain components (essential amino acids, vitamins, minerals, etc.). Certain elements of it are dated (scientists didn't understand the purpose of cholesterol back then), but the general principles hold true.
If you're a tech-minded person who understands very little about biology, you may find the book illustrative. You can find a used copy on Amazon for relatively cheap.