TOPLINE:
Higher plasma levels of omega-6 and omega-3 fatty acids are associated with a lower incidence of cancer. However, omega-3 fatty acids are linked to an increased risk for prostate cancer, specifically.
METHODOLOGY:
- Researchers looked for associations of plasma omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) with the incidence of cancer overall and 19 site-specific cancers in the large population-based prospective UK Biobank cohort.
- They included 253,138 participants aged 37-73 years who were followed for an average of 12.9 years, with 29,838 diagnosed with cancer.
- Plasma levels of omega-3 and omega-6 fatty acids were measured using nuclear magnetic resonance and expressed as percentages of total fatty acids.
- Participants with cancer diagnoses at baseline, those who withdrew from the study, and those with missing data on plasma PUFAs were excluded.
- The study adjusted for multiple covariates, including age, sex, ethnicity, socioeconomic status, lifestyle behaviors, and family history of diseases.
TAKEAWAY:
- Higher plasma levels of omega-6 and omega-3 fatty acids were associated with a 2% and 1% reduction in overall cancer risk per SD increase, respectively (P = .001 and P = .03).
- Omega-6 fatty acids were inversely associated with 14 site-specific cancers, whereas omega-3 fatty acids were inversely associated with five site-specific cancers.
- Prostate cancer was positively associated with omega-3 fatty acids, with a 3% increased risk per SD increase (P = .049).
- A higher omega-6/omega-3 ratio was associated with an increased risk for overall cancer, and three site-specific cancers showed positive associations with the ratio. “Each standard deviation increase, corresponding to a 13.13 increase in the omega ratio, was associated with a 2% increase in the risk of rectum cancer,” for example, the authors wrote.
IN PRACTICE:
“Overall, our findings provide support for possible small net protective roles of omega-3 and omega-6 PUFAs in the development of new cancer incidence. Our study also suggests that the usage of circulating blood biomarkers captures different aspects of dietary intake, reduces measurement errors, and thus enhances statistical power. The differential effects of omega-6% and omega-3% in age and sex subgroups warrant future investigation,” wrote the authors of the study.
SOURCE:
The study was led by Yuchen Zhang of the University of Georgia in Athens, Georgia. It was published online in the International Journal of Cancer.
LIMITATIONS:
The study’s potential for selective bias persists due to the participant sample skewing heavily toward European ancestry and White ethnicity. The number of events was small for some specific cancer sites, which may have limited the statistical power. The study focused on total omega-3 and omega-6 PUFAs, with only two individual fatty acids measured. Future studies are needed to examine the roles of other individual PUFAs and specific genetic variants.
DISCLOSURES:
This study was supported by grants from the National Institute of General Medical Sciences of the National Institutes of Health. No relevant conflicts of interest were disclosed by the authors.
This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication. A version of this article appeared on Medscape.com.