RATIONALE: A low-fat, high-fiber diet may slow the growth of prostate cancer.

PURPOSE: Randomizedphase II trial to compare the effectiveness of a low-fat, high-fiber diet with that of a standard diet in treating patients who have prostate cancer.

OBJECTIVES:

• Compare the inhibition of growth of human prostate cancer cell lines by serum from patients with prostate cancer before and after being fed a low fat, high fiber diet.
• Determine the underlying mechanism through which a low fat, high fiber diet affects the growth of prostate cancer cell lines.
• Determine whether a low fat, high fiber diet inhibits the growth of prostate cancer cell lines through androgen-dependent and/or androgen- independent mechanisms in these patients.
• Determine the growth factors, hormones, and/or binding proteins that may be responsible for affecting the growth of prostate cancer cell lines in these patients.

OUTLINE: This is a randomized study. Patients are randomized to 1 of 2 arms.

• Arm I: Patients receive a low fat, high fiber diet daily for 3 weeks.
• Arm II: Patients receive a control diet containing the standard amounts of fat and fiber.

PROJECTED ACCRUAL: A total of 40 patients (20 per arm) will be accrued for this study within 6 months.

Ages Eligible for Study:  40 Years   -   80 Years,  Genders Eligible for Study:  Both

Criteria

DISEASE CHARACTERISTICS:

• Diagnosis of adenocarcinoma of the prostate
• Previously untreated and on watchful waiting
• Medically able to receive dietary intervention

PATIENT CHARACTERISTICS: Age:

• 40 to 80

Performance status:

• Not specified

Life expectancy:

• Not specified

Hematopoietic:

• Not specified

Hepatic:

• Not specified

Renal:

• Not specified

Other:

• Must be willing to travel to UCLA 3 days a week for 4 weeks to obtain specially prepared foods

PRIOR CONCURRENT THERAPY: Biologic therapy:

• Not specified

Chemotherapy:

• Not specified

Endocrine therapy:

• No concurrent luteinizing hormone-releasing hormone agonists (leuprolide or goserelin)
• No concurrent androgen-receptor blocking agents (flutamide or bicalutamide)
• No concurrent testosterone
• No concurrent insulin
• No concurrent finasteride

Radiotherapy:

• Not specified

Surgery:

• No prior orchiectomy

Other:

• No concurrent saw palmetto supplement