Benign prostatic hyperplasia (BPH) is an age-associated condition that involves enlargement of the prostate gland. This common condition affects approximately 50 percent of men between the ages of 51 and 60. BPH becomes increasingly common as men age, with 90 percent of men at age 85 having this condition. This condition is generally more severe and aggressive in African American men.
The following urinary symptoms are indicative of BPH:
• Incomplete emptying: bladder feels full even after voiding urine
• Increased frequency: need to urinate often, every hour or two
• Intermittency: the need to stop and start several times while urinating
• Urgency: sensation of needing to urinate right away
• Weak stream: a weak or feeble urinary stream
• Straining: need to push or strain to start urine flow
• Nocturia: the need to wake up at night to urinate more than two times
There is no single cause of BPH. Instead, there are likely several different causes, including genetic factors. However, one thing that researchers can agree on is that as men age, their hormone levels change, which affects prostate enlargement. Research has mainly focused on the hormones testosterone, dihydrotestosterone, progesterone, and estrogen.
Testosterone: The first thought for some people is that high testosterone is the likely culprit behind BPH. However, testosterone levels decrease as men age and their testosterone levels drop. We do not find BPH to be a problem with men in their late teens or early twenties, when testosterone levels are high. Moreover, castrated males, who have low testosterone levels, do not have issues with BPH.
Dihydrotestosterone: However, dihydrotestosterone (DHT), a metabolite of testosterone, is associated with BPH. Prostate gland tissue contains the enzyme 5-alpha reductase, which converts testosterone into DHT. The hormone DHT binds to androgen receptors in the prostate and stimulates growth. DHT stimulates prostate growth during fetal development in the womb. However, DHT continues to stimulate prostate growth later in life. Men with BPH have much higher levels of plasma DHT concentration compared to healthy men their age. Furthermore, higher levels of DHT increases the enzymatic activity of 5-alpha-reductase, which may be related to BPH.
Genetic variants in androgen receptors, known as polymorphisms, have been shown in some research to be related to BPH. These receptors, which are found in high concentrations in the prostate gland, influence the binding of testosterone and DHT as well as the regulation of genes that can affect the prostate.
Estrogen: Estrogen is another hormone that influences prostate growth. This hormone is a normal part of the male hormonal system, and most of it is produced in fat, brain, bone, and other tissues. The production of estrogen is primarily controlled by the enzyme known as aromatase, which converts the hormone androstenedione (synthesized by the testicles and adrenal glands) into the estrogen known as estradiol.
Aromatase also converts testosterone from fat and muscle cells into estradiol. Increased activity of aromatase seems to be a causative factor in BPH. Men tend to accumulate fat as they age, which leads to increased aromatase activity as well as decreased testosterone and elevated estrogen levels. Age does not cause estrogen levels to decline the way it does testosterone. The relative excess of estrogen in aging men compared to their testosterone (estrogen/ androgen ratio) influences the later phases of BPH and prostate cancer. There are two types of estrogen receptors inside prostate cells: ERα and ERβ. When estrogen binds to ERα, it stimulates prostate cell growth as well as prostate inflammation. The binding of estrogen to ERβ, conversely, is antigrowth and anti-inflammatory, with the potential for anticancer effects.
Progesterone: Progesterone is also often thought of as a female hormone, but it also plays a role in men’s health. It is produced in the adrenal glands and specialized testes cells known as Leydig cells, which also produce testosterone. The prostate gland has receptors for progesterone.
There are other factors that may play a role in the formation of BPH, including elevated insulin levels (as seen with insulin resistance, e.g., prediabetes and diabetes), insulin-like growth factors, norepinephrine, and angiotensin II. Other risk factors include a greater waist-to-hip ratio, obesity, and genetic predisposition. There are also several nutritional imbalances associated with BPH, such as the high intake of animal protein, saturated fat, and cholesterol; high caloric intake; insufficient consumption of omega-3 fatty acids; and vitamin D deficiency.
Excerpted with permission from Healing The Prostate by Dr. Mark Stengler (Hay House Publishing).
