Does coffee affect vitamin absorption?
I’m wondering if drinking coffee while taking vitamins will affect the efficiency and efficacy of how the vitamins are absorbed. Is it better to eat vitamins first, wait a little, then drink coffee? If so, how long should one wait?
Coffee reduces absorption of B vitamins and may affect vitamin-D receptors. There are many studies on this on nih.gov you may find useful.
ResearchGate is your friend.