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Mistaken Beliefs About Supplements and Vitamins Among Cancer Patients

MedicalResearch.com Interview with:
Dr Rana Conway PhD RNutr 

Research Fellow
Energy Balance & Cancer Group, and Obesity Research Group
Research Department of Behavioural Science and Health
University College London   

MedicalResearch.com: What is the background for this study?

Response: We’ve seen great advances in cancer diagnosis and treatment in recent years which means the number of people living with and beyond a cancer diagnosis is rapidly increasing. The WCRF and CRUK recommend improving diet and exercise to reduce the risks of cancer coming back but we know anecdotally that supplements are sometimes seen as an easier option, and people who’ve had cancer are often interested to know if they should be taking any supplements.   

MedicalResearch.com: What are the main findings? 

Response: We found 1 in 5 people who had been treated for cancer mistakenly thought that taking vitamins or other supplements would help reduce the risk of their cancer coming back. Dietary supplements aren’t recommended by Cancer Research UK (CRUK) as they have not been shown to reduce the risk of cancer recurrence. Instead, people who have had cancer are advised to eat a healthy diet with plenty of fruit and vegetables, and to avoid high calorie foods. Avoiding alcohol and being physically active are also beneficial.

Our research with 1049 people who had had breast, prostate or colorectal cancer found that those who believed supplements were important for reducing their risk of cancer recurrence were three times more likely to take them. As beliefs and use were strongly linked it highlights the need for health care professionals to discuss both with people who have had cancer.

MedicalResearch.com: What should readers take away from your report?

Response: Cancer patients or survivors taking supplements should discuss these with their doctor or another health care professional. There is no evidence that self-prescribed supplements reduce the risks of cancer coming back and they could interfere with treatment. Most of us find healthy eating and exercise advice more difficult to stick to, but the evidence shows these kind of changes can be beneficial – trials with supplements just haven’t shown the same benefits.    

MedicalResearch.com: What recommendations do you have for future research as a result of this work?

Response: The next stage for us, is talking to people who’ve had a cancer diagnosis, we’d like to find out how they made the decision to take particular supplements? have they discussed supplements with a health care professional? and if they believe supplements will help prevent their cancer coming back, where do these beliefs come from?


Conway, RERigler, FVCroker, HALally, PJBeeken, RJFisher, ADietary supplement use by individuals living with and beyond breast, prostate, and colorectal cancer: A cross-sectional surveyCancer2021https://doi.org/10.1002/cncr.34055



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Last Updated on January 6, 2022 by Marie Benz MD FAAD