Question: I am a vegan and have history of breast cancer. I had a mastectomy and chemotherapy 7 years ago. I take Vitamin B-12 every day but recently heard that Vitamin B-12 is not good for people with cancer. Should I stop taking it?
Dr. Hibberd’s answer:
I am glad you have managed with your breast cancer successfully. Vitamin B-12 will not cause your cancer to return, so no problem here. Be careful though, because if you are actually deficient in B-12, you should know whether this is an absorptive problem or a dietary problem.
If it’s dietary, be sure your doctor checks your folate and B-12 levels periodically, because these are often present in unbalanced diets. If it’s an absorptive problem, be sure to work with your doctor to find out what’s causing it. I assume you take oral B-12, so it is most likely your deficiency is a dietary one, but get checked out to be sure.
© 2026 NewsmaxHealth. All rights reserved.