Do food supplements help or hinder cancer treatment?

By Steve Williamson, Consultant Pharmacist in Cancer Services

Last week, Professor Watson (one half of the Nobel prize winning team of Watson and Crick who co-discovered of the structure of DNA in 1953) published his new theory regarding the role of antioxidants in resistance of cancers to drug therapy.  His  hypothesis is that antioxidants found in blueberries, supplements and so called ‘superfoods’ taken to prevent cancer may actually be harmful in patients who already have cancer.

Watson’s new finding has big implications for me as a pharmacist, and for cancer patients, and in a wider sense – anyone using medicines.  Many cancer patients (and sufferers of all illnesses) want to feel empowered, be proactive and do positive things to fight their illness.  This means patients often turn to ‘complementary’ and herbal medicines. As a pharmacist I routinely undertake a medicine history review that includes checking if the cancer patient is taking any ‘complementary medicines’.  Many patients will ask if it is okay to take supplements such as beta carotene, Co Enzyme Q-10, high dose green tea etc.  For a number of years I’ve been  counselling patients to not take ‘antioxidants’ whilst having chemotherapy as the antioxidants are claimed to protect cells from damage by ‘free radicals’ when the purpose of chemotherapy is to damage cells –  so the antioxidants will potentially interfere with the chemotherapy.   It seems that the publication of Professor Watson’s theory has reopened the debate on if we should avoid these foods altogether.

These new findings highlighted to me the importance of offering my advice and opinion on complimentary medicines and interactions. The patient-pharmacist relationship is a two-way street, so take the time to talk to your pharmacist about your diet and about any other treatments you are taking. Your pharmacist will know how seemingly ordinary foods and ‘complementary’ treatments might interact with your medicines.



2 comments on “Do food supplements help or hinder cancer treatment?

  1. Steve thanks for a great blog. I often think that we have to be careful about how we define medicine as “complementary”. As scientists, we need to have an open mind just in case complementary is simply a temporary term for “we don’t know how it works yet”. In the case of nutrition and supplements and their relationship with cancer, this is a perfect example. A hot topic coming to the fore is epigenetics, which explores how certain drugs, nutrients and environmental toxins may change the way genes function without actually changing the gene sequence. This may be brought about by adding methyl groups (DNA methylation) or making modifications to the histone coat that is attached to chromosomes. In this way, pathways controlling cell survival, proliferation and the way they adapt to metabolic changes may be altered. A nice reference here describes how the risk of breast cancer changes with epigenetic modifications in the expression of breast cancer genes by nutrients. Even more fascinating is that these changes may be inherited, this discovery completely turning on its head our idea of genetics and inherited characteristics being indelibly dictated by our ATCG DNA sequences. As pharmacists, we have been accused of all sorts of quackery and of selling “snake oil” when it comes to selling health supplements, but is this a chance for community pharmacy to pull together to do a large scale pharmacoepidemiological study where we can find connections between cancer risk and supplements, and finally answer some of these questions?

    Thanks again for a really interesting topic.

  2. Steve
    A great blog , showing a caring and rational approach. As a community pharmacist I’m afraid my approach has been to veer patients away from such products – but on the different basis that there is no evidence of efficacy regardless of pathology or concurrent medication, with an unknown risk of interaction. Is this still appropriate in terms of EBM. Presumably I should now relate Watson’s concerns as further reason?
    Thank you for an interesting blog
    Peter Dawson

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