Fatigue, inflammation, and-γ3 and γ-6 fatty acid intake among breast cancer survivors

Abstract

Purpose: Evidence suggests that inflammation may drive fatigue in cancer survivors. Research in healthy populations has shown reduced inflammation with higher dietary intake of γ-3 polyunsaturated fatty acids (PUFAs), which could potentially reduce fatigue. This study investigated fatigue, inflammation, and intake of γ-3 and γ-6 PUFAs among breast cancer survivors. Methods: Six hundred thirty-three survivors (mean age, 56 years; stage I to IIIA) participating in the Health, Eating, Activity, and Lifestyle Study completed a food frequency/dietary supplement questionnaire and provided a blood sample assayed for C-reactive protein (CRP) and serum amyloid A (30 months after diagnosis) and completed the Piper Fatigue Scale and Short Form-36 (SF-36) vitality scale (39 months after diagnosis). Analysis of covariance and logistic regression models tested relationships between inflammation and fatigue, inflammation and γ-3 and γ-6 PUFA intake, and PUFA intake and fatigue, controlling for three incremental levels of confounders. Fatigue was analyzed continuously (Piper scales) and dichotomously (SF-36 vitality ≤ 50). Results: Behavioral (P = .003) and sensory (P = .001) fatigue scale scores were higher by increasing CRP tertile; relationships were attenuated after adjustment for medication use and comorbidity. Survivors with high CRP had 1.8 times greater odds of fatigue after full adjustment (P < .05). Higher intake of γ-6 relative to γ-3 PUFAs was associated with greater CRP (P = .01 after full adjustment) and greater odds of fatigue (odds ratio, 2.6 for the highest v lowest intake; P ≤ .05). Conclusion: Results link higher intake of γ-3 PUFAs, decreased inflammation, and decreased physical aspects of fatigue. Future studies should test whether γ-3 supplementation may reduce fatigue among significantly fatigued breast cancer survivors. © 2012 by American Society of Clinical Oncology.