BPH stands for Benign Prostate Enlargement, benign meaning non-cancerous. In other words, you are going to have two Battles of the Bulge as you age: your midsection and your prostate. And let's face it: you don't want a fat prostate any more than you want a fat gut.
BPH (Benign Prostate Enlargement) is still somewhat of a mystery to scientists: no one knows for sure what causes it. Most guys find out the hard way that their prostate goes through a second growth stage at middle age. The first growth stage for the prostate is at puberty where the prostate quadruples in size from about 5 grams to about 20 grams and begins to do its all-important job of manufacturing seminal fluid. Of course, it's the second growth stage in middle age that causes problems for guys, because your prostate is really just the right size post-puberty. You don't need any more growth in that area! (If I could just figure out a way to get the penis to go through a second growth stage, I'd be rich!)
So what's so bad about a fat prostate? Well, BPH (Benign Prostate Enlargement) causes problems because the prostate actually surrounds the urethra, the tube that carries urine from the bladder through the penis. So BPH (Benign Prostate Enlargement) quickly leads to decreased urine flow because the urethra is getting squeezed by its overweight cousin. In some cases, urine flow is completely blocked and requires emergency catheterization - ouch!. Also, as urine flow decreases with BPH (Benign Prostate Enlargement), many guys will strain their bladder muscles trying to urinate. This is the equivalent of doing about 20 Olympic lifts per day in the gym and bladder muscles begin to build up along the bladder wall, leading to less space in the actual bladder. When this starts to occur, many guys start to feel that uncomfortable cramping sensation associated with BPH (Benign Prostate Enlargement). Remember: patience is a virtue, especially when it comes to urinating!
The loss of space in the bladder from BPH (Benign Prostate Enlargement) leads to a vicious cylce of frequent urination while straining, additional muscle growth and so on. Some guys even end up unable to keep the flow going or "dribbling" afterwards. And, of course, another major issue is having to wake up in the middle of the night because of BPH (Benign Prostate Enlargement). As you know from my link on Sleep, any disruption to your sleep can whack your hormones and your memory among other things. Again, patience is a virtue.
So what causes BPH (Benign Prostate Enlargement)? We do know that BPH (Benign Prostate Enlargement) is related to hormones. As I mentioned, the prostate first grows at puberty. Furthermore, males castrated before puberty do not develop BPH (Benign Prostate Enlargement). But, that said, BPH (Benign Prostate Enlargement) is still a mystery in many ways. Scientists have studied many factors such as exercise and sexual activity and not come up with good correlations (except for a few all-critical ones that we show later on this page). Adding to the mystery of BPH (Benign Prostate Enlargement) is the fact that many guys find that the symptoms come and go seeming without apparent reason.
One factor that does seem to be tied in is the accumulation of estrogen that is part of again for almost all males. BPH has been shown to be correleated to estradiol levels. In fact, one study found that ALL cases of BPH involved eleveated estrogen receptors, whereas only about half of prostate cancer cases did.  See this link on How to Lower Estrogen Levels.
Also, doctors for years focused on DHT (dihydrotestosterone) as the cause of BPH. However, researchers now believe that estradiol (and SHBG) are the root cause of it and that DHT may even block it!  Furthermore, it could be the T/E2 (testosterone to estradiol) ratio according to one older study. 
Why You Don't Want BPH (Benign Prostate Enlargement):
Besides all the unpleasant symptoms that I mentioned above, BPH (Benign Prostate Enlargement) is one of the conditions where the cure can be worse than the disease. Consider these standard treatments for BPH (Benign Prostate Enlargement), depending on the severity of the condition:
1) Cialis. You may be given Cialis. Of course, Cialis has its advantages, but often very large dosages are given leading a man to become dependent on the dosage or even resistant later on. In addition, nasty side effects such as tinnitus and vision loss (temporary and sometimes permanent) are all too common. I have had experienced mild tinnitus and also get bad heartburn when I take too much. For additional information, see my links on Viagra Resistance and Cialis Dependency.
2) Alpha Blockers. You may have to start taking alpha blockers, traditionally medications for high blood pressure. These work quickly but they are, of course, drugs and long term effects are not that well-known. Alpha blockers also have a fairly high percentage of side effects.
3) Proscar / Propecia / Finasteride. Some physicians may try to give you Proscar (finasteride) for BPH (Benign Prostate Enlargement), which supposedly works by limiting the enzyme that converts testosterone to DHT (a more powerful androgen of hair loss fame). This is quite effective but takes much longer to work generally, sometimes up to six months. Some researchers believe that Proscar reduces tumor size but promotes the most powerful forms of prostate cancer. CAUTION: Many men appear to have what is called "Finasteride Syndrome", where they basically lose their testosterone long term. The effects are nasty as libido and mood are often affected as well. For more information, see m link on The Risk of Propecia / Proscar.
4) TURP. One common and effective surgery is called TURP (or "Roto Rootering"). This generally relieves the symptoms of BPH (Benign Prostate Enlargement) but, because the prostate is in such close proximity with the bladder, urethra and rectum, which means problems with TURP can include erectile dysfunction, secondary retrograde ejaculation, acute urinary retention and so on. There are other surgical procedures as well, but all carry the same risks.
The bottom line is that you want to avoid BPH (Benign Prostate Enlargement) at all costs. How do you that? Well, as usual, the answer points primarily to diet, which I cover in this link in great detail on How To Prevent BPH (Benign Prostate Enlargement) Through Diet.
1) Oncology, 1993, 50:259-263, "Immunohistochemical Evaluation of Estrogen Receptor Status in Benign Prostatic Hypertrophy and in Prostate Carcinoma and the Relationship to Efficacy of Endocrine Therapy"
2) PNAS June 7, 1994 vol. 91 no. 12 5402-5405, "Estradiol causes the rapid accumulation of cAMP in human prostate"
3) The Prostate, 4(3), 1983, "Plasma estradiol, free testosterone, sex hormone binding globulin binding capacity, and prolactin in benign prostatic hyperplasia and prostatic cancer"