Dietary Intake of N-3 and N-6 Polyunsaturated Fatty Acids and Risk of Cancer: Meta-Analysis of Data from 32 Studies

Abstract

Background

Large epidemiological studies have yielded conflicting results regarding the relationship between polyunsaturated fatty acids (PUFAs) and cancers. Here, we performed a meta-analysis to examine the link between dietary intake of n-3 and n-6 PUFAs and cancer risk.

Materials and methods

We performed a search on PubMed, EMBASE, and the Cochrane Library. Studies that reported adjusted relative risk (RR) estimates with 95% confidence intervals (CI) for the associations of interest were included.

Results

Thirty-two studies involving 1,445,732 participants were included. Colorectal, breast and prostate cancer had been analyzed in our study. Specifically, for colorectal cancer, total n-3 PUFAs, marine n-3 PUFAs, α-linolenic acids (ALA) and n-6 PUFAs were not associated with the risk of it (RR 1.04, 95%CI 0.85–1.28; RR 0.99, 95%CI 0.89–1.09; RR 1.05, 95%CI 0.93–1.19; RR 1.02, 95%CI 0.94–1.11, respectively). For breast cancer, only marine n-3 PUFAs, but not total n-3 PUFAs, ALA, and n-6 PUFAs, was associated with a lower risk of it (RR 0.70, 95%CI 0.55–0.91). For prostate cancer, ALA and n-6 PUFAs also have no association with the risk of it.

Conclusions

Most subtypes of PUFAs are probably not related to cancers. However, additional high-quality trials are warranted to corroborate the findings of this meta-analysis.

Acknowledgments

We thank Professor Jie Yang for his comments on this manuscript and linguistic advice.

Conflict of Interest

The authors have declared no conflicts of interest.

Author contributions

Conceptualization: Jian Liu and Zhenxing Wang; Methodology: Jian Liu and Xianqing Li; Software: Jian Liu and Jinfei Hou; Validation: Nengqiang Guo and Zhenxing Wang; Analysis: Jian Liu and Xianqing Li; Writing-Original draft preparation: Jian Liu; Writing-Review & Editing: Jiaming Sun and Nengqiang Guo.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (No. 81701922 to Zhenxing Wang).