Single Vitamins or Botanical Supplements
Most meta-analyses that have evaluated the effect of a single vitamin or botanical supplement on cancer incidence have found no association.
A meta-analysis of 49 intervention trials including 287,304 individuals found no link netween cancer incidence and supplementation with selenium, zinc, magnesium, beta carotene, the omega-3 fatty acid eicosapentaenoic acid, or vitamins D, C, or K.9 Similar results found by another meta-analysis, in which data from 19 RCTs of 68,954 individuals found that omega-3 fatty acid supplementation did not affect cancer incidence compared with placebo (RR, 1.10; 95% CI, 0.97-1.24).10 For bladder cancer, however, a meta-analysis of 14 RCTs found that beta carotene supplementation significantly increased the risk of developing bladder cancer (RR, 1.44; 95% CI, 1.00-2.09).10
Although several studies showed inconsistent or no effect of folic acid supplementation on the incidence of CRC,6,11 a meta-analysis of patients with irritable bowel disease found that folic acid supplementation reduced the risk of CRC (hazard ratio [HR], 0.58; 95% CI, 0.37-0.80).12
Studies evaluating the use of vitamin D and/or calcium supplements generally demonstrated a decreased risk for developing cancer. A Cochrane review and meta-analysis of 18 RCTs of 50,623 participants found that vitamin D3 supplementation significantly reduced the risk of cancer-related mortality compared with placebo (RR, 0.88; 95% CI, 0.78-0.98), but did not affect cancer occurrence, including among individuals who enrolled with low baseline serum levels of vitamin D.13 Meta-analyses also demonstrated a modest but significant decrease in the risk of developing CRC with calcium supplementation (RR, 0.86; 95% CI, 0.79-0.95), and pancreatic cancer with high amounts of vitamin D supplementation compared with the lowest vitamin D intake (RR, 0.90; 95% CI, 0.83-0.98).6,8 Vitamin D supplementation was also associated with a lower incidence of hematologic malignancies (HR, 0.80; 95% CI, 0.65-0.99).14 However, a RCT of 1 year of treatment with 1000 U to 3000 U of vitamin D3 or placebo found no difference in mammographic breast density between groups.15
There is currently no evidence that the use of multivitamins or general vitamin and/or antioxidant supplements reduces the risk of developing cancer. Most of the studies of single vitamins or botanical supplements have not been able to definitely link their use to changes in cancer incidence; the impact of vitamin D and calcium levels on cancer risk appear to be exceptions to this rule. Meta-analyses of RCTs suggest that supplementation with calcium may reduce the risk of CRC, and vitamin D may reduce the risk of pancreatic cancer or hematologic malignancies. Lastly, folic acid supplementation may be protective against CRC for individuals with irritable bowel disease.
Taken together, these data suggest that there is no clear, overarching evidence that nutraceuticals help prevent cancer.
- National Institutes of Health Office of Dietary Supplements. Dietary supplements: what you need to know. https://ods.od.nih.gov/HealthInformation/DS_WhatYouNeedToKnow.aspx. Updated June 17, 2018. Accessed November 7, 2018.
- Grand View Research. Dietary Supplements Market Size, Share & Trend Analysis Report By Ingredient (Botanicals, Vitamins, Minerals, Amino Acids, Enzymes), By Product, By Application, By End-use, And Segment Forecasts, 2018–2024. San Francisco, CA: Grand View Research; 2018. https://www.grandviewresearch.com/industry-analysis/dietary-supplements-market/toc. Accessed November 7, 2018.
- Martínez ME, Jacobs ET, Baron JA, Marshall JR, Byers T. Dietary supplements and cancer prevention: balancing potential benefits against proven harms. J Natl Cancer Inst. 2012;104(10):732-739.
- Wang J-B, Abnet CC, Fan J-H, Qiao Y-L, Taylor PR. The randomized Linxian Dysplasia Nutrition Intervention Trial after 26 years of follow-up: no effect of multivitamin supplementation on mortality. JAMA Intern Med. 2013;173(13):1259-1261.
- Dawsey SP, Hollenbeck A, Schatzkin A, Abnet CC. A prospective study of vitamin and mineral supplement use and the risk of upper gastrointestinal cancers. PLoS One. 2014;9(2):e88774. doi: 10.1371/journal.pone.0088774
- Heine-Bröring RC, Winkels RM, Renkema JMS, et al. Dietary supplement use and colorectal cancer risk: a systematic review and meta-analyses of prospective cohort studies. Int J Cancer. 2015;136(10):2388-2401.
- Myung S-K, Kim Y, Ju W, Choi HJ, Bae WK. Effects of antioxidant supplements on cancer prevention: meta-analysis of randomized controlled trials. Ann Oncol. 2010;21(1):166-179.
- Pais R, Dumitraşcu DL. Do antioxidants prevent colorectal cancer? A meta-analysis. Rom J Intern Med. 2013;51(3-4):152-163.
- Chang YJ, Myung S-K, Chung ST, et al. Effects of vitamin treatment or supplements with purported antioxidant properties on skin cancer prevention: a meta-analysis of randomized controlled trials. Dermatology. 2011;223(1):36-44.
- Park S-J, Myung S-K, Lee Y, Lee Y-J. Effects of vitamin and antioxidant supplements in prevention of bladder cancer: a meta-analysis of randomized controlled trials. J Korean Med Sci. 2017;32(4):628-635.
- Liu Y, Wang X, Sun X, Lu S, Liu S. Vitamin intake and pancreatic cancer risk reduction: a meta-analysis of observational studies. Medicine (Baltimore). 2018;97(13):e0114. doi: 10.1097/MD.0000000000010114
- Schwingshackl L, Boeing H, Stelmach-Mardas M, et al. Dietary supplements and risk of cause-specific death, cardiovascular disease, and cancer: a systematic review and meta-analysis of primary prevention trials. Adv Nutr. 2017;8(1):27-39.
- Zhang Y-F, Gao H-F, Hou A-J, Zhou Y-H. Effect of omega-3 fatty acid supplementation on cancer incidence, non-vascular death, and total mortality: a meta-analysis of randomized controlled trials. BMC Public Health. 2014;14:204. doi: 10.1186/1471-2458-14-204
- Qin T, Du M, Du H, Shu Y, Wang M, Zhu L. Folic acid supplements and colorectal cancer risk: meta-analysis of randomized controlled trials. Sci Rep. 2015;5:12044. doi: 10.1038/srep12044
- Burr NE, Hull NA, Subramanian V. Folic acid supplementation may reduce colorectal cancer risk in patients with inflammatory bowel disease: a systematic review and meta-analysis. J Clin Gastroenterol. 2017;51(3):247-253.
- Bjelakovic G, Gluud LL, Nikolova D, et al. Vitamin D supplementation for prevention of cancer in adults. Cochrane Database Syst Rev. 2014;(6):CD007469. doi: 10.1002/14651858.CD007469.pub2
- Ammann EM, Drake MT, Haraldsson B, et al. Incidence of hematologic malignancy and cause-specific mortality in the Women’s Health Initiative randomized controlled trial of calcium and vitamin D supplementation. Cancer. 2017;123(21):4168-4177.
- Brisson J, Bérubé S, Diorio C, et al. A randomized double-blind placebo-controlled trial of the effect of vitamin D3 supplementation on breast density in premenopausal women. Cancer Epidemiol Biomarkers Prev. 2017;26(8):1233-1241.