DISEASE CHARACTERISTICS:

* Healthy male volunteers
* Digital rectal examination (DRE) deemed not suspicious for prostate cancer performed within 364 days prior to study entry

* Participants with a suspicious DRE are ineligible even if a recent or subsequent biopsy is negative for cancer
* Total prostate-specific antigen ≤ 4.0 ng/mL within 364 days prior to study entry
* No prior prostate cancer or high-grade (grade 2-3) prostatic intraepithelial neoplasia

PATIENT CHARACTERISTICS:

Age:

* See Disease Characteristics

Performance status:

* Not specified

Life expectancy:

* Not specified

Hematopoietic:

* Not specified

Hepatic:

* Not specified

Renal:

* Not specified

Cardiovascular:

* Systolic blood pressure \< 160 mm Hg
* Diastolic blood pressure \< 90 mm Hg
* No history of hemorrhagic stroke

Other:

* No malignancies within the past 5 years except basal cell or squamous cell skin cancer
* No uncontrolled medical illness
* No retinitis pigmentosa

PRIOR CONCURRENT THERAPY:

Biologic therapy

* Not specified

Chemotherapy

* Not specified

Endocrine therapy

* Not specified

Radiotherapy

* Not specified

Surgery

* Not specified

Other

* At least 7 years since prior randomization to SWOG-9217, with completion of end-of-study biopsy requirement
* No additional concurrent selenium or vitamin E (contained in individual supplements, antioxidant mix, or multivitamin)
* Concurrent multivitamins allowed (supplied on study)
* No concurrent anticoagulation therapy (e.g., warfarin)
* Concurrent prophylactic aspirin (average daily dose no greater than 175 mg/day) allowed

* Concurrent daily aspirin dose ≤ 81 mg for participants receiving clopidogrel
* Concurrent anti-hypertension medication allowed
* No concurrent participation in another study involving a medical, surgical, nutritional, or life-style intervention (unless no longer receiving the intervention and are in the follow-up phase only)