Thank you for those links. I will read today. One more question, what is the consensus on the effect of oral contraceptives on B-12? I have been on the pill for the better part of 20 years. I really want to get my B-12 level up and hope the pill won't interfere with supplementing. If so, I will just come off of it! Thank you so much for any info on this. I have read conflicting information.