Table 11.
RCTs examining the effect of dietary patterns on serum PSA concentrations among men with PCa or increased PCa risk.
| First Author | Origin | Masking | Duration | Patients | Interventions | Results |
|---|---|---|---|---|---|---|
| Hébert [206] | US | Open-label | 6 mo | n = 54 men with a confirmed PCa, treated by prostatectomy, or radiation therapy | 1. Diet (low meat and dairy, increased intake of whole grains, soybeans and by-products, other beans, and vegetables), PA (45-min sessions), and stress reduction sessions (n = 29) 2. Usual treatment (n = 25) |
No difference in Δ PSA was noted by intervention status. Men increasing their fruit intake experienced no PSA rise. |
| Demark-Wahnefried [208] | US | Single-blind | until prostatectomy (30.7 d) | n = 161 scheduled at least 21-d before prostatectomy | 1. Usual diet (n = 41) 2. Flaxseed-supplemented diet (30 g/d) (n = 40) 3. LFD (<20% fat) (n = 40) 4. Flaxseed-supplemented (30 g/d) LFD (<20% fat) (n = 40) |
Over the presurgical study period serum PSA decreased in all arms, with no differences in change observed between arms. |
| Ornish [210] | US | NR | 1 yr | n = 98 men with early, biopsy-proven PCa after 1 yr, PSA 4–10 ng/mL and Gleason score ≤ 7 | 1. Intensive lifestyle program promoting a vegan diet, supplemented with soy (1 serv of tofu + 58 g fortified soy PRO drink), fish oil (3 g/d), vitamin E (400 IU/d), Se (200 μg/d), and vitamin C (2 g/d), moderate aerobic PE (walking 30 min, 6 d/wk), stress management (yoga-based stretching, breathing, meditation, imagery, relaxation for a 60 min/d), and 1-h support group once weekly to enhance adherence to the intervention. Diet: fruits, vegetables, whole grains (complex CHO), legumes, and soy products, low in simple CHO and with 10% fat (n = 44) 2. Usual diet (n = 49) |
Changes in serum PSA from baseline to 12 mo were different between groups, with favorable changes in the experimental group. Serum PSA decreased (0.25 ng/mL, or 4%) from baseline in the treatment arm, but increased in the control group. |
| Kellogg Parsons [211] | US | Single-blind | 2 yr | n = 443 men (50–80 yrs) with biopsy-proven PCa | 1. Counseling behavioral intervention by phone promoting the intake of ≥7 vegetable serv/d (n = 226) 2. Written information about diet and PCa (n = 217) |
There were no significant differences in TTP between groups. |
| Aronson † [212] | US | Single-blind | 4–6 wks | n = 55 patients undergoing radical prostatectomy | 1. Western diet (40% fat, 15% PRO, 45% CHO, 15 g fiber/d, n-6:n-3 FA ratio of 15:1) (n = 26) 2. LFFO diet (15% fat, 15% PRO, 70% CHO), 39 g fiber/d and 5 × 1.1 g fish oil caps/d (200 mg EPA, 367 mg DHA) with a ratio of n-6:n-3 FA to 2:1 (n = 26) |
No differences were noted in the PSA concentrations of participants in the two groups. |
| Aronson [213] | US | NR | 4 wks | n = 18 men with PCa who did not receive prior therapy | 1. High-fiber LFD (15% fat, 30% PRO, 55% CHO), 35 g soy PRO/d, and 35 g fiber/d) (n = 9) 2. Western diet (40% fat, 30% PRO, no soy, 30% CHO, 10 g fiber/d) (n = 9) |
No differences were observed in the PSA concentrations. |
| Antwi [142] | US | NR | 6 mo | n = 54 men with a history of PCa and rising PSA concentrations post-prostatectomy/radiation | 1. Dietary modifications, PA, and mindfulness-based stress reduction training, including shopping guidelines (n = 29) 2. Standard care (n = 25) |
No differences were observed in the PSA concentrations between participating groups. |
| Tariq [223] ‡ | CA | NR | 4 mo | n = 14 healthy men with hyperlipidemia | 1. Diet high in soluble fiber (approx. 25–30 g fiber/1000 kcal, ≤20% fat, ≤20% PRO, ≥60% CHO) (n = 9) 2. Diet high in insoluble fiber (approx. 25–30 g fiber/1000 kcal, ≤20% fat, ≤20% PRO, ≥60% CHO) (n = 5) |
Serum PSA concentration was lower with the soluble than the insoluble fiber diet. |
| Freedland [217] | US | NR | 6 mo | n = 42 patients with PCa initiating ADT | 1. LCD (≤20g CHO/d) plus walking (≥30 min for ≥5 d/wk) 2. Usual diet and exercise patterns |
No differences were observed in the PSA concentrations. |
| Freedland [218] | US | NR | 6 mo | n = 34 men with PCa and BCR after local treatment | 1. LCD (≤20g CHO/d) (n = 14) 2. Usual diet (n = 20) |
PSA values did not differ between groups. The proportion of patients with slowed PSADT was greater in the LCD arm. |
| Li [219] | US | NR | 4 yr | n = 40 men post-prostatectomy, at high risk for recurrence | 1. LFD (15% fat), high-fiber (18 g/1000 kcal) diet supplemented with 40 g soy PRO + individual counseling sessions (n = 26) 2. USDA recommended diet (n = 14) |
No significant changes in PSA were reported between groups. |
| Carmody [220] | US | NR | 3 mo | n = 24 men previously treated for PCa and their partners | 1. 11 dietary and cooking classes (emphasizing plant-based foods and fish -salmon-, vegetables-, cruciferous varieties-, and whole grains, as well as soy foods, with avoidance of meat, poultry, and dairy) (n = 10) 2. Control group (n = 14) |
No change was found in the rate of PSA increase between the two groups; the mean PSADT for the intervention participants was substantially longer. |
| Shike [221] | US | NR | 2 yrs | n = 1230 men with normal DRE results, PSA concentrations < 3 ng/mL | 1. Intensive counseling towards an LFD, high in fiber, fruits, and vegetables (n = 627) 2. Standard brochure on a healthy diet (n = 603) |
No difference was observed in the distributions of the PSA slopes, the PSA slopes per se, or the % of high PSA concentrations between groups. The incidence of PCa at 4 yrs was similar. |
| Eastham Š [222] | US | Open-label | 4 yrs | n = 1197 men | 1. LFD high in fiber, fruits, and vegetables (n = 611) 2. Usual diet (n = 586) |
No difference was noted in serum PSA concentrations by dietary intervention. |
ADT, androgen deprivation therapy; ALA, alpha-linolenic acid; AS, active surveillance; BCR, biochemical recurrence; CI, confidence intervals; CHO, carbohydrates; CoQ10, coenzyme Q10; DHA, docosahexaenoic acid; DRE, digital rectal examination; EPA, eicosapentaenoic acid; FA, Fatty acids; GLA, γ-linolenic acid; LCD, Low-carbohydrate diet; LFD, Low-fat diet; LFFO, low fat/fish oil; NR, not reported; NS, not significant; PCa, prostate cancer; PE, physical exercise; PRO, proteins; PSA, prostate-specific antigen; PSADT, prostate-specific antigen doubling time; RCT, randomized controlled trials; TEI, total energy intake; TTP, time to progression (PSA ≥ 10 ng/mL); USDA, United States Department of Agriculture. † phase II trial; ‡ cross-over trial; Š post-hoc analysis.