Collagen peptides can increase bone density

Hello, readers! Welcome to a bonus letters column. We are happy to report that you are keeping our inboxes busy, so we’ll dive right in.

– We recently wrote about collagen peptides, a protein abundant in collagen, skin and bone. It is available as a nutritional supplement, which is the subject of one reader’s question: “I have read that collagen supplements can increase bone mineral density, and ha…