Dietary supplement use common among adults with cancer despite no proven benefit
Click Here to Manage Email Alerts
Use of dietary supplements appeared common among adults who had been diagnosed with cancer, many of whom believed the supplements could lower the risk for disease recurrence despite a lack of proven benefit, according to a study in Cancer.
The results reflect a need for health care professionals to discuss use of dietary supplements with their patients, researchers wrote.
“Most of us find healthy eating and exercise advice more difficult to stick to, but the evidence shows these kinds of changes can be beneficial. Trials with supplements just haven’t shown the same benefits,” Rana E. Conway, BSc (Hons), PhD, RNutr, research fellow in the obesity group at the research department of behavioral science and health at University College London, told Healio. “There is no evidence that self-prescribed supplements reduce the risks of cancer coming back, and they could interfere with treatment.”
Conway and colleagues evaluated 1,049 adults (mean age, 64.4 years; 62.1% women; 93.6% white) who had been diagnosed with breast (54.4%), prostate (25.2%) or colorectal (20.4%) cancer in the United Kingdom between 2012 and 2015.
Researchers collected survey results from the patients and asked them to provide contact information if they wanted to learn more about a trial of a lifestyle intervention. Those who expressed interest completed additional baseline assessments, including two 24-hour dietary recalls.
Conway and colleagues used these data to explore associations between dietary supplement use and demographics, health behaviors and beliefs about dietary supplements and cancer.
Results showed 40% of patients reported dietary supplement use and 19% believed dietary supplements could reduce cancer recurrence risk.
“We knew some people thought supplements help prevent cancer or prevent it coming back, but we had no idea how many,” Conway told Healio. “One in five is quite considerable; our participants were well educated (one-third had degrees or higher levels of education), yet this misunderstanding wasn't unusual. It would be interesting to know where this idea came from.”
Researchers also identified associations of dietary supplement use with:
- female sex (OR = 2.48; 95% CI, 1.72-3.56);
- meeting 5-a-day fruit and vegetable recommendations (OR = 1.36; 95% CI, 1.02-1.82); and
- a belief in the importance of dietary supplements to reduce risk for cancer recurrence (OR = 3.13; 95% CI, 2.35-4.18).
Those with obesity appeared less likely to use dietary supplements (OR = 0.58; 95% CI, 0.38-0.87).
The most common supplements among all patients included fish oils (used by 13%), calcium with or without vitamin D (9.1%) and multivitamins and minerals (8.2%). Fifteen percent of those diagnosed with breast cancer used calcium with or without vitamin D.
Conway said further research will include talking with people who have had a cancer diagnosis to find out how and why they decided to take the supplements, whether they had discussed it with a health care professional, and if they believed the supplements prevented cancer recurrence (and where those beliefs originated).
“Ideally supplements would be discussed on an individual basis: taking into account any cancer treatment, other health conditions and medication and also the individual's diet,” Conway said. “For this population more generally, it would be good to emphasize that there is good evidence that a healthy diet and physical activity are beneficial; supplements are seen as an easier option, but we just don't have the evidence that they prevent cancer coming back.”
For more information:
Rana E. Conway, BSc (Hons), PhD, RNutr, can be reached at Department of Behavioral Science and Health, University College, 1-19 Torrington Place, London, United Kingdom, WC1E 7HB; email: r.conway@ucl.ac.uk.
Collapse
Click Here to Manage Email Alerts