Prostate Cancer Prevention: What the Evidence Supports, and What It Does Not

Last updated: August 25, 2026

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Men ask this constantly, and the honest answer is less satisfying than most articles make it sound. Almost everything published about diet and prostate cancer comes from observational studies — watching what people eat and seeing who later develops disease. That kind of evidence is useful for generating ideas and poor at proving them, which is why the advice keeps changing.

An earlier version of this article presented all of it as evidence-based prevention, with percentages, serving counts and milligram thresholds. It has been rewritten and sorted by how much confidence each item actually deserves. Two recommendations have been withdrawn entirely.

• Urology center Bangkok hospital Thailand Booking online 02-310-3009 bhquro@bdms.co.th
• Samitivej Sriracha hospital Chonburi 088-022-1445

First: what cannot be changed

These matter more than anything in the diet section, and the earlier version gave them a single clause in passing.

• Age, by a wide margin the strongest factor.
• Ethnicity — incidence and aggressiveness differ substantially between populations.
• Family history, particularly a father or brother affected, and more so if they were diagnosed young.
• Inherited genetic changes, of which BRCA2 is the most important. It raises the risk of prostate cancer and of a more aggressive form, and it runs in families alongside breast and ovarian cancer. This is genuinely actionable: it changes when screening should start and how closely a man is followed, and it is worth raising if there is a pattern of cancer in your family. It was absent from the earlier version altogether.

Nothing in the rest of this article outweighs these. A man with a strong family history who eats well is still a man with a strong family history.

Reasonably well supported

• Not smoking. Smoking has not been convincingly shown to cause prostate cancer in the first place — but in men who already have it, the risk of dying of it is roughly doubled in smokers. That makes stopping one of the most worthwhile things on this page, and it acts on heart disease and lung cancer at the same time.
• Keeping weight down. Obesity is associated with more aggressive disease and with worse outcomes after treatment, and it also lowers testosterone, worsens metabolic health and complicates surgery. The link to simply developing prostate cancer is weaker than the link to developing the dangerous kind.
• Limiting alcohol. Heavy drinking is associated with higher risk. The earlier version quoted a 5% increase per daily drink and 21% at four drinks; those figures are removed here, because relative increases of that size from observational data carry more precision than they deserve. The direction is reliable enough to act on; the decimal places are not.
• Physical activity. Worth doing on its own merits, and there is reasonable evidence it improves outcomes in men who already have prostate cancer. The earlier version called exercise the easiest way to prevent prostate cancer; the evidence that it prevents the disease occurring is considerably weaker than the evidence that it helps everything else, including how well men tolerate treatment.

Plausible, unproven, and harmless to follow

These come from observational studies. Eating this way is good for you regardless, which is the main reason to do it — not the prostate claim attached.

• Less red and processed meat, and less saturated animal fat. The earlier version specified more than five servings of cooked meat a week as the threshold; that number came from a particular study rather than from anything established.
• Cruciferous vegetables — broccoli, cauliflower, cabbage, Brussels sprouts.
• Soy and green tea. Repeatedly associated with lower rates, never confirmed in a trial.
• Coffee. Associated with a lower rate of aggressive disease in several studies. Not a reason to start drinking it, and not a reason to stop.
• Very high calcium intake — mainly from supplements rather than food — is one of the more consistently reported dietary associations with higher risk.

Withdrawn: the supplement advice

This is the most important change to the page.

Selenium

The earlier version stated that high selenium intake gives a 50 to 60% reduction in prostate cancer risk. That figure came from observational data — and it was then tested directly and failed.

The SELECT trial randomised more than 35,000 men to selenium, vitamin E, both, or placebo, precisely because the observational evidence looked so promising. Selenium prevented nothing. Vitamin E was associated with significantly more prostate cancer than placebo. It is the clearest demonstration in this entire field that a large apparent benefit in dietary studies can vanish, or reverse, when properly tested — and it is the reason a figure like 50 to 60% should never have been published as a recommendation.

Do not take selenium or vitamin E supplements to prevent prostate cancer.

Lycopene and tomato sauce

The earlier version recommended two to four servings of tomato sauce a week as a way to decrease risk. That has been withdrawn for two reasons: the lycopene evidence is observational and has never been confirmed in a trial, and processed sauces carry a sugar load that works against the weight advice given above. Tomatoes are good food; cooking them at home with olive oil gives the same absorption benefit without the trade-off. This is set out in full under what the evidence on lycopene really supports.

Vitamin D

Deficiency has been associated with higher risk, but supplementing to prevent prostate cancer is not supported. Correcting a genuine deficiency is worth doing for other reasons, particularly for bone health.

The general rule this page now follows: food, yes; capsules, no. Supplements are not concentrated versions of the foods they came from, and in this field the one that was properly tested caused harm.

The thing prevention cannot do

No diet detects a cancer that is already there. Whether to have a PSA test is a separate decision, and one worth making deliberately rather than by default — see should I have a PSA test, and, if you already have a raised result, what a high PSA actually means. For the wider dietary picture see diet and prostate cancer.

Symptoms that need assessment rather than a change of diet

In an emergency in Thailand, call 1669.

• Visible blood in the urine or semen.
• New bone pain in the back, hips or ribs, or unexplained weight loss.
• Inability to pass urine with a painful full bladder.
• New leg weakness or numbness, or loss of bladder or bowel control, in a man known to have prostate cancer — emergency assessment.
• A father or brother diagnosed with prostate cancer young, or a family pattern of breast, ovarian or pancreatic cancer — worth raising early rather than waiting for symptoms.

Frequently Asked Questions About Prostate Cancer Prevention

Should I take selenium to prevent prostate cancer?

No. An earlier version of this article quoted a 50 to 60% risk reduction from observational data. The SELECT trial then randomised more than 35,000 men and found selenium prevented nothing, while vitamin E was associated with significantly more prostate cancer than placebo. That recommendation has been withdrawn.

What actually has decent evidence behind it?

Not smoking, keeping weight down, limiting alcohol and staying active. None is dramatic and none is prostate-specific, and they act on heart disease at the same time — which is what will kill most men.

Does smoking cause prostate cancer?

The link to developing it is not convincing. The link to dying of it is: men with prostate cancer who smoke have roughly double the cancer-specific mortality. Stopping matters most after diagnosis, which is the opposite of what men usually assume.

How much do diet and lifestyle matter compared with family history?

Considerably less. Age, ethnicity, family history and inherited genetic changes such as BRCA2 outweigh everything in the dietary section. If close relatives were affected, particularly young, or if there is a family pattern of breast, ovarian or pancreatic cancer, that is worth discussing — it changes when screening should begin.

Should I eat tomato sauce for my prostate?

This article previously recommended two to four servings a week, and that has been withdrawn. The lycopene evidence is observational and unconfirmed by trial, and commercial sauces carry a sugar load that works against the weight advice on this same page. Tomatoes cooked at home with olive oil are the sensible version.

Arranging a consultation

For prostate risk assessment or a PSA discussion, Dr. Soarawee Weerasopone sees patients at Bangkok Hospital Headquarters and at Samitivej Sriracha Hospital in Chonburi on 088-022-1445. Bring any previous PSA results with their dates, and details of cancer in close relatives including the age at which they were diagnosed.

Bangkok Hospital Telemedicine is available for patients who cannot attend in person, including international patients — arrange it in advance by email to the Urology department at bhquro@bdms.co.th. Samitivej Sriracha is in-person only. Enquiries about cost are answered by the hospital, not by this website.

Disclaimer: This content is written and reviewed by Dr. Soarawee Weerasopone, a board-certified urologist at Bangkok Hospital Headquarters, and is intended for education only. It is not medical advice, diagnosis or a prescription for any individual, and no advice, diagnosis or prescription is given through personal messaging channels or social media. Dr. Soarawee operates no public social media account; any account offering private consultation in his name is fraudulent. In an emergency in Thailand, call 1669.