Pilot study of dietary fat restriction and flaxseed supplementation in men with prostate cancer before surgery: exploring the effects on hormonal levels, prostate-specific antigen, and histopathologic features.
Level 4 - case-series / case-control
Historically controlled interventional study
PubMed 11445478 · doi:10.1016/s0090-4295(01)01014-7
What was done
Twenty-five men with prostate cancer awaiting prostatectomy followed a low-fat (≤20% kcal), flaxseed-supplemented (30 g/day) diet for a mean of 34 days (range 21 to 77 days). Pre- and post-intervention serum levels of total cholesterol, total testosterone, free androgen index, and prostate-specific antigen (PSA) were measured. Tumor tissue obtained at prostatectomy was evaluated for proliferation (MIB-1) and apoptosis (TUNEL) and compared to matched historical controls.
What was found
Significant decreases occurred in total serum cholesterol (201 ± 39 to 174 ± 42 mg/dL), total testosterone (422 ± 122 to 360 ± 128 ng/dL), and free androgen index (36.3% ± 18.9% to 29.3% ± 16.8%) (all P < 0.05). PSA was 8.1 ± 5.2 ng/mL before and 8.5 ± 7.7 ng/mL after diet across all participants (P = 0.58), and 7.1 ± 3.9 to 6.4 ± 4.1 ng/mL in those with Gleason ≤ 6 (n = 19, P = 0.10). The tumor proliferation index was 5.0 ± 4.9 in the diet group versus 7.4 ± 7.8 in historical controls (P = 0.05). Apoptotic index scores were significantly higher in the diet group (P = 0.01), and both proliferation (P = 0.049) and apoptosis (P = 0.017) correlated with duration on the diet.
Why it matters
This pilot study suggests that a short-term dietary intervention combining fat restriction and flaxseed may alter systemic androgen levels and cellular biomarkers of prostate tumor growth.
Limits
The sample was very small (n = 25) with a variable intervention window (21–77 days) and used historical controls rather than a concurrent randomized control group. Fat restriction was co-administered with flaxseed, preventing isolation of specific dietary components.
Cited by
- supports Dietary fat restriction combined with flaxseed supplementation lowers androgens in men with prostate cancer before surgery.