Results from animal studies suggest that
omega-3 fatty acids from marine sources are protective against
cancer. To determine whether adipose tissue and erythrocyte membrane
fatty acid composition could serve as
biomarkers of essential
fatty acid consumption in subjects with
prostate cancer, we compared fish consumption, which was estimated using a food frequency survey, to the
omega-3 fatty acid content of adipose tissue and erythrocyte membranes. The study was conducted using 127 men who had undergone a prostate biopsy. All subjects were recruited from a university hospital urology clinic. African Americans comprised 23% of the subjects, and 70% were diagnosed with
prostate cancer. We found a correlation of 0.44 with 95% confidence intervals (CIs) = 0.29-0.57 between reported fish consumption and the
omega-3 fatty acid eicosapentaenoic acid composition in erythrocyte membranes and 0.38 with 95% CI = 0.21-0.53 when the dietary survey was compared to
eicosapentaenoic acid in adipose tissue. The survey/
biomarker correlations in cases were not significantly different from the correlations in controls. The study had 90% power to detect a 0.35 difference between correlations. These results suggest that the presence of
prostate cancer does not affect the adipose tissue or erythrocyte membrane
biomarkers of
fatty acid consumption, and that erythrocyte membranes are as useful as
biomarkers as is adipose tissue. Our findings corroborate previous studies that found that tissue
biomarkers can reflect past
fatty acid consumption and support the use of
biomarkers in case-control studies using
cancer patients.