this link explains how long it takes to replace the bllod and red cells. https://www.blood.co.uk/the-donation-process/after-your-donation/how-your-body-replaces-blood/ I'm pretty sure that if donating blood had been proven to result in tooth loss in diabetics, then they wouldn't be allowed to donate. My bg is within normal levels so I'm not concerned. I have donated since age 17 (a time ago!) and my Mum needed several pints when undergoing chemotherapy, so donating is very important to me. In fact it was one of my first concerns when I was diagnosed. I will be giving my 74th donation in July.