“Know thyself.” No one knows exactly who came up with this wise phrase (it was definitely a Greek, but which one is uncertain), but I think we all agree that there’s something to it. Knowing yourself is powerful because it’s an ability that other animals don’t have. While they live blissfully ignorant in the moment, subject to their impulses, we can act intelligently in order to achieve the best possible outcome for ourselves. Specifically, we can have knowledge about how our bodies work, and we can use this knowledge to live for maximum health. So, here’s my question: do you know what your prostate gland does (or did if it was removed)?

If you don’t know what the prostate gland is or does, you’re not alone. More than three billion people go about their day-to-day routines carrying this special gland in their abdomens, but hardly anyone except people who study medicine actually know what it is. It’s one of the glands that make the male body what it is, but it’s still a mystery to so many people.

What is the prostate gland, and what does it do? It’s about the size of a walnut, and it sits right between the bladder and the penis. The urethra, the tube that carries urine from the bladder, travels through the center of the prostate. The prostate gland has two simple functions (as far as we know): it produces a fluid that liquefies ejaculate and nourishes and protects sperm, and it squeezes this fluid into the urethra during orgasm. The fluid is important for reproduction because it is alkaline, meaning it neutralizes the acidic, spermicidal fluids of the vagina and allows sperm to swim along unhindered.

From this information, you can guess why a malfunctioning prostate can cause all sorts of problems for the male body. I don’t know whose idea it was to send the urethra directly through the center of the prostate, but they clearly did not consider the fact that this arrangement would make it difficult for older men to urinate. The enlarged prostate puts pressure on the urethra, which constricts urine flow. This condition is known clinically as benign prostatic hyperplasia, or an enlarged but otherwise healthy prostate, and it affects almost all men over the age of fifty.

The prostate gland is technically not necessary for survival, so men diagnosed with serious prostate cancer sometimes opt for a radical prostatectomy—removal of the entire prostate. This most obviously affects the constitution of semen, but nerve damage during surgery has made it difficult for many men to get an erection or stop urine flow post-surgery. Problems with urinary incontinence are less common than ED is fairly common. This can be devastating for some men, but it is important to remember (1) that there are medical treatments for ED and (2) that penetration is not the only way to enjoy sex with your partner. (I’ll let you figure out the details there.)

So, now that you know what the prostate gland is and does, what should you do? First of all, know your prostate. If you’re over the age of 40, ask your doctor if it’s time for a prostate exam. As always, take care to eliminate inflammatory and high-glycemic foods from your diet and load up on fruits and vegetables. And don’t forget to exercise. Your prostate, like the rest of your body, responds well to your diet and lifestyle. Know thyself, and care for thyself.