We've reported many times on connections between omega-3 and omega-6 fatty acids and breast cancer.
There's substantial evidence that omega-3 fatty acids tend to curb cancer growth and enhance the efficacy of chemo and radiation treatment (Baracos VE et al. 2004; Wendel M et al. 2009; Spencer L et al. 2009; Bougnoux P et al. 2010).
However, we lack clinical evidence of efficacy, and epidemiologic studies have produced mixed results (Signori C et al. 2009; Sala-Vila A, Calder PC 2011).
On the plus side, a study among 56,007 French women found that breast cancer risk was lower among women whose estimated omega-3 intake was in the top one-fifth (Thiébaut AC et al. 2009).
Conversely, the risk of breast cancer in the French women was higher among those in the top one-fifth of estimated omega-6 intake.
Now, the unusually meaningful results of a new study show that breast cancer patients with higher blood levels of omega-3s suffer less inflammation and fatigue than their peers.
The opposite trend was seen for women with higher omega-6/omega-3 ratios, who showed higher levels of inflammation and more fatigue.
Importantly, these associations reflect the actual blood levels of these fats, and do not rely on estimates of omega-6 and omega-3 blood levels based on diet questionnaires.
The study was led by Catherine M. Alfano, Ph.D., of the Office of Cancer Survivorship at the National Cancer Institute.
Connections seen between blood fats and fatique, inflammation
Dr. Alfano and an international group of colleagues recruited 633 breast cancer survivors (Alfano CM et al. 2012).
The women gave blood samples 30 months after diagnosis and took standard fatigue assessment tests 39 months after diagnosis.
The participants' blood was analyzed for markers of chronic and acute inflammation … C-reactive protein (CRP) and serum amyloid A protein, respectively. (To learn about inflammation and tumor growth, see “Breast Cancer Linked to Inflammation.”)
As the authors reported, their results indicated that the women with higher intake of omega-3s had lower inflammation (CRP) levels and less physical fatigue.
After adjusting the results to account for other factors, breast cancer survivors with high CRP [inflammation ] levels were almost twice (1.8 times) as likely to experience fatigue.
And the women with higher blood levels of omega-6 fatty acids relative to omega-3s had higher CRP levels and were more than twice (2.6 times) as likely to suffer from fatigue.
As the NCI-led team wrote, “Considering the high prevalence of fatigue among cancer survivors, effective treatment could have a significant health impact.”
They proposed that “Future studies should test whether omega-3 supplementation may reduce fatigue among significantly fatigued breast cancer survivors” (Alfano CM et al. 2012).
Alfano CM, Imayama I, Neuhouser ML, Kiecolt-Glaser JK, Wilder Smith A, Meeske K, McTiernan A, Bernstein L, Baumgartner KB, Ulrich CM, Ballard-Barbash R. Fatigue, Inflammation, and ω-3 and ω-6 Fatty Acid Intake Among Breast Cancer Survivors. J Clin Oncol. 2012 Mar 12. [Epub ahead of print]
Baracos VE, Mazurak VC, Ma DW. n-3 Polyunsaturated fatty acids throughout the cancer trajectory: influence on disease incidence, progression, response to therapy and cancer-associated cachexia. Nutr Res Rev. 2004 Dec;17(2):177-92.
Bougnoux P, Hajjaji N, Maheo K, Couet C, Chevalier S. Fatty acids and breast cancer: sensitization to treatments and prevention of metastatic re-growth. Prog Lipid Res. 2010 Jan;49(1):76-86. Epub 2009 Aug 26. Review.
Sala-Vila A, Calder PC. Update on the relationship of fish intake with prostate, breast, and colorectal cancers. Crit Rev Food Sci Nutr. 2011 Oct-Nov;51(9):855-71. Review.
Signori C, El-Bayoumy K, Russo J, Thompson HJ, Richie JP, Hartman TJ, Manni A. Chemoprevention of breast cancer by fish oil in preclinical models: trials and tribulations. Cancer Res. 2011 Oct 1;71(19):6091-6. Epub 2011 Sep 20. Review.
Spencer L, Mann C, Metcalfe M, Webb M, Pollard C, Spencer D, Berry D, Steward W, Dennison A. The effect of omega-3 FAs on tumour angiogenesis and their therapeutic potential. Eur J Cancer. 2009 Aug;45(12):2077-86. Epub 2009 Jun 1. Review.
Thiébaut AC, Chajès V, Gerber M, Boutron-Ruault MC, Joulin V, Lenoir G, Berrino F, Riboli E, Bénichou J, Clavel-Chapelon F. Dietary intakes of omega-6 and omega-3 polyunsaturated fatty acids and the risk of breast cancer. Int J Cancer. 2009 Feb 15;124(4):924-31.
Wendel M, Heller AR. Anticancer actions of omega-3 fatty acids--current state and future perspectives. Anticancer Agents Med Chem. 2009 May;9(4):457-70. Review.