Supplements
Why Consider Supplements?
While undergoing cancer treatment, patients may experience nutritional deficiencies, treatment-related side effects, or compromised immune function that supplements can help address. Certain supplements such as vitamin D, omega-3 fatty acids, and melatonin have shown potential to improve treatment response, reduce side effects, and support overall survival. When used judiciously and under medical supervision, supplements can play a valuable supportive role in comprehensive cancer care.
Key Lifestyle Insights
- Metformin – This diabetes drug may slow cancer growth by lowering blood sugar and blocking pathways that cancer cells use to grow.
- Melatonin – This natural sleep hormone may help the immune system fight cancer and make treatments work better.
- Fish Oil (Omega-3s) – Omega-3s from fish oil can slow cancer by reducing inflammation and support the immune system in recognizing cancer.
- Vitamin D – Helps control how cells grow and may stop cancer from spreading or forming new blood vessels.
- Ginseng – A traditional herbal remedy that may help the body fight cancer by boosting immunity and helping cancer cells die off.
- Multivitamins – Can fill in nutritional gaps and support general health, especially when combined with healthy lifestyle habits.
- Folate (Vitamin B9) – Helps repair DNA, but too much from supplements may feed certain cancers, so balance is key.
- Selenium – This mineral supports the immune system and protects cells, but too much may be harmful in people who already get enough.
- St. John’s Wort – Often taken for depression, this herbal remedy can reduce the effectiveness of chemotherapy and immunotherapy by inducing CYP3A4, which causes faster drug clearance.
- Grapefruit Juice, Goldenseal, and Licorice Root (glycyrrhizin) – These common supplements are known CYP3A4 inhibitors that can dangerously increase blood levels of many cancer drugs, potentially leading to heightened toxicity and adverse effects.
Discover the Impacts of Different Supplements
Impact of Supplements on Treatment Success
A growing body of research indicates that behavioral and supplemental interventions can significantly influence cancer treatment outcomes across a wide range of cancer types. One of the most consistently supported factors is treatment adherence, which has been associated with a 21% increased risk of mortality when not maintained (HR: 1.21; 95% CI: 1.12–1.31) (Neugut et al., 2016). Among pharmacologic adjuncts, metformin has shown broad anticancer activity with a 34% reduction in cancer-specific mortality across multiple cancer types (HR: 0.66; 95% CI: 0.54–0.81) (Nie et al., 2021). Similarly, melatonin use in conjunction with standard therapies reduced mortality by approximately 34% in a meta-analysis of 21 trials (HR: 0.66; 95% CI: 0.59–0.73) (Wang et al., 2012). Nutritional supplements such as fish oil, which is high in omega-3 fatty acids, have demonstrated survival benefits in certain cancers and may improve treatment response due to their anti-inflammatory and immune-modulating effects, although findings across all cancer types remain mixed (Manson et al., 2019). Vitamin D supplementation, particularly in individuals with normal BMI, has been associated with a 38% reduction in advanced cancer incidence (HR: 0.62; 95% CI: 0.45–0.86) (Chandler et al., 2020).
Other supplements, while widely used, show more nuanced or limited benefits. Folate, for instance, exhibits a dual effect: dietary intake is associated with reduced mortality in esophageal cancer (HR: 0.41; 95% CI: 0.25–0.69), while high supplemental intake may increase recurrence risk in bladder and prostate cancer (Mason et al., 2018; Vollset et al., 2011). Multivitamins have shown no significant effect on recurrence or survival across large cancer cohorts (HRs generally near 1.00), although some benefits are noted when combined with healthy lifestyle behaviors (Ng et al., 2010). Selenium supplementation appears to reduce mortality in selenium-deficient individuals (e.g., HR: 0.63 in breast cancer) but may increase risk in those with adequate levels (Kristal et al., 2014). Ginseng has demonstrated a 29–30% reduction in mortality and recurrence risk in breast cancer cohorts (Chen et al., 2006), likely due to its immunomodulatory and apoptotic properties. Collectively, these findings underscore the importance of personalized, evidence-based integration of supplements and behavioral interventions into cancer treatment to optimize survival outcomes.
- Chandler, P. D., Chen, W. Y., Ajala, O. N., et al. (2020). Effect of vitamin D3 supplements on development of advanced cancer: A secondary analysis of the VITAL randomized clinical trial. JAMA Network Open, 3(11), e2025850.
- Chen, Z., Gu, K., Zheng, Y., et al. (2006). Association of ginseng use with survival and quality of life among breast cancer patients. American Journal of Epidemiology, 163(7), 645–653.
- Kristal, A. R., Darke, A. K., Morris, J. S., et al. (2014). Baseline selenium status and effects of selenium and vitamin E supplementation on prostate cancer risk. Journal of the National Cancer Institute, 106(3), djt456.
- Manson, J. E., Cook, N. R., Lee, I. M., et al. (2019). Marine omega-3 fatty acids and prevention of cardiovascular disease and cancer. New England Journal of Medicine, 380(1), 23–32.
- Mason, J. B., Dickstein, A., Jacques, P. F., et al. (2018). Is folic acid safe for non–muscle-invasive bladder cancer patients? American Journal of Clinical Nutrition, 107(3), 371–379.
- Neugut, A. I., Subar, M., Wilde, E. T., et al. (2016). Association between prescription co-payment amount and compliance with adjuvant hormonal therapy in women with early-stage breast cancer. Journal of Clinical Oncology, 34(15), 1735–1741.
- Ng, K., Meyerhardt, J. A., Chan, J. A., et al. (2010). Multivitamin use is not associated with cancer recurrence or survival in patients with stage III colon cancer. Journal of Clinical Oncology, 28(27), 4354–4363.
- Nie, Z., Zhu, H., Gu, M., Lu, S., & Yu, H. (2021). Association of metformin with cancer incidence and mortality: A meta-analysis. Cancer Medicine, 10(5), 1822–1835.
- Vollset, S. E., Clarke, R., Lewington, S., et al. (2011). Effects of folic acid supplementation on overall and site-specific cancer incidence during the randomised trials: Meta-analyses of data on 50,000 individuals. BMJ, 344, d5190.
- Wang, Y., Jin, Y., Kang, H., & Xu, D. (2012). Melatonin as an adjuvant treatment for cancer: A systematic review and meta-analysis. PLoS ONE, 7(11), e49749.
