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

最終更新日: 8月 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 Two recommendations have been withdrawn entirely.

• タイ・バンコク病院 泌尿器科センター オンライン予約 02-310-3009 bhquro@bdms.co.th
• サミティベート・シラチャ病院(チョンブリ) 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.

• 年, 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.

セレン

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.

ビタミン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 PSA検査を受けるべきですか？, and, if you already have a raised result, 実際のPSA値が高いということはどういう意味ですか？. For the wider dietary picture see 食事と前立腺がん.

食事の変化ではなく評価が必要な症状

タイで緊急の場合は、次の番号に電話してください 1669.

• 尿や精液に血が見える。.
• 背中、腰、肋骨の新しい骨痛、または原因不明の体重減少。.
• 痛みを伴う満腹膀胱で排尿できない。.
• 前立腺がんの疑いのある男性において、新しい下肢のしびれやしびれ、または膀胱や腸の機能喪失 — 緊急評価。.
• 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.

診察のご予約について

For prostate risk assessment or a PSA discussion, Dr. Soarawee Weerasopone sees patients at Bangkok Hospital Headquarters また、チョンブリー県の Samitivej Sriracha Hospital でも次の曜日に診察を行っています 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.

来院が難しい海外の患者さんを含め、バンコク病院の遠隔診療をご利用いただけます。事前に泌尿器科へ次のメールアドレスまでご連絡のうえ、ご予約ください: bhquro@bdms.co.th。サミティベート・シラチャー病院は対面診療のみです。費用に関するお問い合わせには病院が対応しており、本ウェブサイトでは対応しておりません。

免責事項: 本コンテンツは、Bangkok Hospital Headquarters に勤務する泌尿器科専門医(認定医)の Dr. Soarawee Weerasopone が執筆・監修したもので、教育目的のみを意図しています。個々の方に対する医学的助言、診断、処方ではなく、個人メッセージやソーシャルメディアを通じて助言、診断、処方を行うことはありません。Dr. Soarawee は公開のソーシャルメディアアカウントを運営しておらず、彼の名前で個別相談を提供するアカウントは詐欺です。タイで緊急の場合は、次の番号に電話してください 1669.