Effects of ω-3 Fatty Acids and Catechins on Fatty Acid Synthase in the Prostate: A Randomized Controlled Trial

Abstract

Animal and human studies suggest fish oil and green tea may have protective effect on prostate cancer. Fatty acid synthase (FAS) has been hypothesized to be linked to chemoprotective effects of both compounds. This study evaluated the independent and joint effects of fish oil (FO) and green tea supplement (epigallocatechin-3-gallate, EGCG) on FAS and Ki-67 levels in prostate tissue. Through a double-blinded, randomized controlled trial with 2 × 2 factorial design, 89 men scheduled for repeat prostate biopsy following an initial negative prostate biopsy were randomized into either FO alone (1.9 g DHA + EPA/day), EGCG alone (600 mg/day), a combination of FO and EGCG, or placebo. We used linear mixed-effects models to test the differences of prostate tissue FAS and Ki-67 by immunohistochemistry between pre- and post-intervention within each group, as well as between treatment groups. Results did not show significant difference among treatment groups in pre-to-post-intervention changes of FAS (P = 0.69) or Ki-67 (P = 0.26). Comparing placebo group with any of the treatment groups, we did not find significant difference in FAS or Ki-67 changes (all P > 0.05). Results indicate FO or EGCG supplementation for a short duration may not be sufficient to produce biologically meaningful changes in FAS or Ki-67 levels in prostate tissue.

Trial registration: ClinicalTrials.gov NCT00253643.

Figure 1

Randomized controlled trial sample size flow chart

Figure 2

Comparison of prostate benign tissue fatty acid synthase (FAS) immunohistochemistry H-score level changes between treatment groups. Changes in FAS level from pre- to post-intervention between treatment groups were compared using mixed effect model. Values shown indicate least-squares means of (LSMEANS ± SE) pre-to-post change of FAS level by treatment group.

Figure 3

Comparison of prostate benign tissue Ki-67 immunohistochemistry number of positive cells/high-power field (200x, which is 10x objective eyepiece x 20x magnification) level changes between treatment groups. Changes in Ki-67 level from pre- to post-intervention between treatment groups were compared using mixed effect model. Values shown indicate least-squares means of (LSMEANS ± SE) pre-to-post change of Ki-67 level by treatment group.