i don't have access to my old comp which has all my notes. i remember hearing him say it in a audio interview maybe 4 years ago. he was discussing different types of milk. maybe try a search in the audio transcripts to see if it was one of the interviews that was transcribed. a quick search on this site shows a couple of threads where this is discussed. it appears the calcium helps tryptophan convert to b3, but i'm not sure you will find the issue of dry milk not doing this function within the search results. maybe i just created this claim in my head. sorry i couldn't be of more help.Never heard that before, have you got a source?