Nick asked
I am taking vitamin D supplement, Vitamin B12, and metformin for my Polycystic Ovarian Syndrome. I just want to know if there is any interactions with grapefruit. i have a high cholesterol that's why i included grapefruit on my diet. thank you so much.
Answer
There is no interaction between any of the medications you mentioned in your question and grapefruit. It's a good thing that you ask since grapefruit can interact with so many different types of drugs!
We wrote extensively about the grapefruit interaction in one of our articles found here:
/grapefruit-juice-drug-interactions.html
As we wrote, grapefruit can interact with medications in two ways. It can either interfere with the metabolizing enzyme known as CYP3A4 or it can interact with a drug transporter known as OATP. Metformin, vitamin D and vitamin B12 are not affected by changes in either CYP3A4 or OATP.
The only thing I would say is that SOMETIMES metformin can cause a decrease in absorption of vitamin B12 obtained through our diet so it is good that you are supplementing with it. Other than that possible minor interaction, you are good to go!
