I have looked to see if there is any evidence that taking vitamin supplements can affect the result of the FIT screening test, and I cannot see that it does. I can see online that vitamin c is mentioned but that seems to be in relation to the FOB test, we do not use the FOB test in the UK anymore now, it had been replaced, since 2019 with the FIT test.
I have also looked at the patient information from the NHS about having the test done and it does not mention or advise not to take vitamins. You can see this information, which also tells you what will happen if you have a positive result, on the NHS website here
I hope this has been helpful to read. Please get back to us if you need any more information or support. You may find it helpful to talk things through with one of the nurses on our helpline. The number to call is Freephone 0808 800 4040 and the lines are open from 9am till 5pm Monday to Friday.
