Dietary total antioxidant capacity and risk of cancer: a systematic review and meta-analysis on observational studies

Mohammad Parohan; Alireza Sadeghi; Seyed Reza Khatibi; Morteza Nasiri; Alireza Milajerdi; Mahmoud Khodadost; Omid Sadeghi

doi:10.1016/j.critrevonc.2019.04.003

Dietary total antioxidant capacity and risk of cancer: a systematic review and meta-analysis on observational studies

Crit Rev Oncol Hematol. 2019 Jun:138:70-86. doi: 10.1016/j.critrevonc.2019.04.003. Epub 2019 Apr 4.

Authors

Mohammad Parohan¹, Alireza Sadeghi², Seyed Reza Khatibi³, Morteza Nasiri⁴, Alireza Milajerdi⁵, Mahmoud Khodadost⁶, Omid Sadeghi⁷

Affiliations

¹ Gerash University of Medical Sciences, Gerash, Iran; Department of Cellular and Molecular Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran.
² Department of Cellular and Molecular Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran.
³ Torbat Heydariyeh University of Medical Sciences, Torbat Heydariyeh, Iran.
⁴ Department of Operating Room Technology, School of Paramedicine, Qom University of Medical Sciences, Qom, Iran; Student Research Committee, Department of Surgical Technology, School of Nursing and Midwifery, Shiraz University of Medical Sciences, Shiraz, Iran.
⁵ Students' Scientific Research Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran.
⁶ Department of Epidemiology, School of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran (i) Department of Epidemiology, School of Public Health, Iran University of Medical Sciences, Tehran, Iran; Department of Epidemiology, School of Public Health, Iran University of Medical Sciences, Tehran, Iran.
⁷ Students' Scientific Research Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran. Electronic address: omidsadeghi69@yahoo.com.

PMID: 31092388
DOI: 10.1016/j.critrevonc.2019.04.003

Abstract

Background: Recent studies have shown that dietary total antioxidant capacity (D-TAC) may affect risk of cancer; however, findings are conflicting. Hence, we aimed to summarize the current evidence on the association between D-TAC and risk of cancer.

Methods: We searched the online databases of PubMed, ISI Web of Science, Scopus, ProQuest, Science Direct and Embase until October 2018 using relevant keywords. To pool data, fixed- or random-effects models were used where appropriate.

Results: In total, 19 studies including 8 prospective and 11 case-control studies with 721429 individuals and 16159 cases of cancer were included in the current systematic review and meta-analysis. Combining 15 effect sizes from 6 prospective and 8 case-control studies revealed a significant inverse association between D-TAC (obtained from ferric reducing antioxidant power (FRAP)) and risk of cancer (combined effect size: 0.86, 95% CI: 0.81-0.92, P < 0.001). Such inverse association was also seen for D-TAC obtained from other methods including trolox equivalence antioxidant capacity (TEAC) (combined effect size: 0.80, 95% CI: 0.70-0.90, P < 0.001), total radical trapping antioxidant parameter (TRAP) (combined effect size: 0.69, 95% CI: 0.62-0.78, P < 0.001) and oxygen radical absorbance capacity (ORAC) (combined effect size: 0.72, 95% CI: 0.52-1.00, P = 0.04). In addition, a significant non-linear association was found between D-TAC (based on FRAP and TRAP) and cancer risk (P-nonlinearity<0.001). Based on linear dose-response meta-analysis, a-10 mmol/day increase in FRAP and a-5 mmol/day increase in TRAP and TEAC were associated with 9%, 17% and 14% reduction in risk of cancer, respectively. Furthermore, D-TAC was inversely associated with risk of colorectal (combined effect size: 0.82, 95% CI: 0.75-0.89, P < 0.001), gastric (combined effect size: 0.63, 95% CI: 0.53-0.73, P < 0.001), and endometrial cancer (combined effect size: 0.78, 95% CI: 0.69-0.89, P < 0.001).

Conclusions: Diet with high antioxidant capacity might have protective effects against cancer.

Keywords: Antioxidants; Cancer; Diet; Dose-response; Meta-analysis.

Publication types

Meta-Analysis
Systematic Review

MeSH terms

Antioxidants*
Diet*
Female
Humans
Neoplasms / epidemiology*
Risk

Substances

Antioxidants