Why is beer the enemy of the prostate?

Regular beer consumption can cause prostate problems, as well as heart, liver, and pancreas problems. This is due to the alcohol content in beer, albeit at lower concentrations than other beverages like wine, cocktails, or spirits.

But as Paracelsus said, "It's the amount that makes the poison." Alcohol itself is toxic, carcinogenic, and linked to the development of various cardiovascular diseases, among other things, but our body is capable of tolerating and eliminating small amounts.

This tells us that the occasional glass of wine or a cold beer in the summer isn't zero risk, but rather so low that the pleasure can compensate. The choice of whether to drink occasionally must therefore be balanced against one's personal risk profile and health goals (source).

WHY BEER IS BAD FOR THE PROSTATE

Beer can irritate the prostate. All urologists agree.
Alcohol can be an immediate problem for those suffering from LUTS or benign hyperplasia. Ethanol is a diuretic and can irritate the bladder, worsening urgency and nocturia, especially in the evening/night. Clinical reviews recommend limiting alcohol and fluids in the evening to improve symptoms (source).
In addition to alcohol, hops are also harmful to the prostate.
Hops (Humulus lupulus) are a herbaceous plant that grows wild in both temperate zones of the planet, and their inflorescence is a fundamental ingredient in brewing beer, along with malt, water, and yeast.

Hops have been used in beer production since the Middle Ages, and today very few beers are produced without them.
Hops contain substances similar to estrogen, the commonly occurring female hormone, called phytoestrogens. Estrogens are also present in men and perform several important functions, but if the amount of these hormones exceeds that of androgens, such as testosterone, general problems such as fatigue, hypertension, mood disorders, or problems affecting the sexual sphere, such as loss of libido, erectile dysfunction, infertility, and gynecomastia, can occur.
The pharmacological effects of these molecules are similar to those of estrogen, so much so that they are used in the treatment of women undergoing menopause, when estrogen production decreases (source).

Hops contain 8-prenylnaringenin, the most potent phytoestrogen known, but its concentration in hops is too low to define its role in prostate problems.
However, recent data show that the intake of phytoestrogens from moderate beer consumption is not sufficient to cause clinically significant hormonal imbalances in men (source 1, 2, 3, 4).
The pharmacological effects of these molecules are similar to those of estrogen, so much so that they are used in the treatment of women undergoing menopause, when estrogen production decreases (source).

EFFECT OF ESTROGEN ON THE PROSTATE

In the prostate, an imbalance in estrogen hormones can lead to congestion of the prostate tissue or an increase in the gland's volume, leading to the development of benign prostatic hyperplasia (source), primarily causing urinary problems. Some evidence also links increased estrogen levels in men to an increased risk of developing prostate cancer (source).
Beer is said to prevent prostate cancer, thanks to the presence of a substance in hops called xanthohumol. While this substance has been shown in laboratories to have anti-neoplastic effects, it's also true that consuming sufficient quantities to achieve this effect would require drinking several liters of beer, which would otherwise cause other problems related to alcohol, for example.