Vits & Minerals

I have SBC and have started Letrozole and Ribociclib. I know the basic rules of no pomegranate, grapefruit juices or Seville oranges but wondered if it was okay for me to take a multivitamin and cod liver oil supplement. I already take vit D and calcium which has been advised.
Thank you.


I’m sure the Nurses will reply shortly . You’ve done the right thing by asking as it becomes tricky once you’ve had BC in regard to supplements . I know Vitamin E is contraindicated for BC

Hi again

Somehow hit the post button too soon . Just to say at a routine appointment with my BCN she was able to give advice about supplements they had looked into for other patients and she was also able to contact a Pharmacist to get clarification re some others. Another avenue if you are unsure or are thinking of trying others .


Hi michellem55

Thank you for posting about supplements. Many people ask about vitamin and herb supplements as they want to do as much as possible to be healthy. There is often the belief that vitamins and herbs are safe as they are considered natural.

There is much we don’t know about supplements and herbal remedies. For many products there is a lack of research to support their use, and some can interfere with conventional medicines including cancer treatments so it’s really important to seek advice as you are taking letrozole and ribociclib.

You can search this American website, Memorial Sloan Kettering Cancer Centre, for information about individual herbs and vitamins. Each has sections on existing evidence and what known interaction there is with other medications. They have a page on cod liver oil here. You may find that that some herbs have different names in America. Cancer Research UK have a page dedicated to vitamins, diet supplements and cancer that you may find useful.

As @JoanneN says, we would always suggest that you speak to your treatment team, GP, or a pharmacist before taking any supplements.

Your specialist may recommend that you avoid, or stop taking, herbs or supplements as some of these may affects treatments such as surgery, radiotherapy or chemotherapy.

Tell your specialist about any supplements you’re taking or considering taking, including:

  • vitamin and mineral supplements (certain vitamins, particularly high dose antioxidants (including vitamins A, C and E, co-enzyme Q10 and selenium) may affect treatments such as radiotherapy or chemotherapy)
  • herbal remedies (some herbs may have anticoagulant (blood thinning) properties)
  • any treatments that are bought over the counter or online

Eating a balanced diet is the best way to get a healthy range of vitamins and minerals. You make find our Diet and breast cancer booklet helpful to look at.

Do call our helpline if you would like to talk this through or have any further questions. The helpline team have time to listen to your concerns, talk things through and signpost you to more support and information. Your call will be confidential, and the number is free from UK landlines and all mobile networks. The number is 0808 800 6000, (Relay UK - prefix 18001).

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Best wishes


Breast Care Nurse

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