The Encyclopedia of Natural Medicine, 3rd Ed.

Prostate Enlargement (BPH)


• Symptoms of bladder outlet obstruction (increased urinary frequency, urgency, and need to urinate during the night; difficulty beginning to urinate; urine stream starts and stops; slow urine flow)

• Enlarged, nontender prostate

The prostate is a doughnut-shaped gland about the size of a walnut that lies below the bladder and surrounds the urethra. The prostate secretes a thin, milky, alkaline fluid that increases sperm motility, lubricates the urethra, and helps prevent infection. Prostate secretions are extremely important to successful fertilization of the egg as well as the male sexual experience.

Prostate enlargement refers to benign prostatic hyperplasia (BPH), a condition that affects more than 50% of men in their lifetime. The actual incidence increases with advancing age, from approximately 5 to 10% at age 30 to 50% at age 50 and more than 90% in men older than 85.1

Although BPH is usually more of a bothersome condition that can dramatically affect quality of life, it can also lead to serious consequence, as it can progress to urinary retention, with an accompanying risk of recurrent urinary tract infections, bladder stones, and occasionally kidney failure.


Genetic predisposition plays a minor role in BPH, particularly when BPH occurs in a younger man.13 Genetics can set the stage, but ultimately BPH is a condition caused by the influence of dietary, lifestyle, and environmental factors on the metabolism of male sex hormones (androgens). Levels of testosterone, particularly free testosterone, decrease with age after the fifth decade. By contrast, hormones such as prolactin, estradiol, sex-hormone-binding ligand, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) are all increased. The ultimate effect of these changes is that within the prostate there is an increased concentration of dihydrotestosterone (DHT), the potent androgen derived from testosterone. This increase is largely due to a decreased rate of removal combined with an increase in the activity of the enzyme that converts testosterone to DHT.4 Estrogens come into play because they inhibit the proper excretion of testosterone and DHT.


WARNING: Prostate disorders can be diagnosed only by a physician. Do not self-diagnose. If you are experiencing any symptoms associated with BPH or prostate cancer, see your physician immediately for proper diagnosis.


Diagnostic Considerations

It is often recommended that men over the age of 40 have yearly prostate exams. This exam is not high-tech. It simply involves a doctor inserting a gloved finger into the rectum and feeling the lower part of the prostate for any abnormality. However, in the case of BPH, often the prostate has not enlarged to a point that can be recognized by physical exam. And in the case of cancer, a digital exam is not reliable enough.

The classic enlarged prostate due to BPH will usually feel softer than normal and may be two to three times larger than normal. In BPH, the prostate is not tender; this differentiates it from prostatitis—an infection of the prostate. The classic finding in prostatic cancer is that the prostate feels much harder and its border is not as well-defined as that of a healthy prostate.

The definitive diagnosis of BPH can be made with the aid of ultrasound measurements. However, because the symptoms of BPH and prostate cancer can be similar, a simple blood test is used to differentiate BPH from the more serious prostate cancer. The blood test measures the levels of prostate-specific antigen (PSA), a protein that is produced in the prostate. The PSA test is regarded as a highly significant and sensitive marker for prostate cancer. The normal value for PSA is less than 4 ng/ml. A level above 10 ng/ml is highly indicative of prostate cancer.

There has been concern that the use of PSA as a screening test for prostate cancer is not reliable enough and leads to many unnecessary biopsies in the attempt to rule out prostate cancer. Making matter worse, many forms of prostate cancer are very slow-growing, so that the treatment is often more serious than the disease. Although an elevated level of prostate-specific antigen indicates prostate cancer about 90% of the time, it must be kept in mind that midrange elevations in PSA can be caused by BPH, and that in some instances there may be prostate cancer yet PSA levels are not elevated. Despite the fact that this test is not perfect, it is a simple, relatively noninvasive test that can provide valuable information.

If you are a man over the age of 50 and if any of your immediate relatives—father, brother, or uncle—has had prostate cancer, an annual prostate exam and PSA test are a very good idea. See the chapter “Prostate Cancer (Prevention)” for more information.

Therapeutic Considerations

If left untreated, BPH can eventually obstruct the bladder outlet, resulting in the retention of urine and eventually kidney damage. As this situation is potentially life-threatening, proper treatment is crucial. Surgery may be indicated in patients for whom medical therapy has not worked, who have recurrent infection, or who display signs of kidney failure. In the past, medical treatment involved a procedure known as transurethral resection of the prostate. Because this surgery is associated with a high rate of morbidity (sexual dysfunction, incontinence, and bleeding) and often makes matters worse, it should be avoided unless absolutely necessary. Surgical procedures that use microwaves or lasers are also available. Generally, these newer procedures are less expensive than transurethral resection of the prostate and have fewer complications, although subsequent therapies are often required.5


There is an association between greater physical activity and lower rates of BPH, and there is also an association between abdominal obesity and BPH.6,7 Higher caloric intake not also encourages abdominal obesity but also increases sympathetic nervous system activity (the fight-or-flight response); this may cause the smooth muscle of the prostate to contract, resulting in a worsening of urinary symptoms. Interestingly, higher caloric intake does not seem to increase BPH risk when accompanied by increased physical activity.7

It seems possible that physical activity may serve a threefold purpose: (1) it may increase blood flow to the area, allowing the body to remove wastes efficiently; (2) it can decrease sympathetic stress responses, thus relaxing prostatic tissue; and (3) it can reduce excess abdominal weight, decreasing sympathetic nervous system activity and thus relaxing the prostate/rectal region and improving blood flow into and out of the area.


Diet appears to play a critical role in the health of the prostate. Diets high in overall fat, particularly saturated fat, are associated with an increased risk of BPH, as are diets high in red meat.7 A study of Chinese farmers revealed a correlation between diets higher in animal products and the frequency of BPH (91.1% of those those eating diets high in animal products had BPH vs. 11.8% in those not eating animal protein).8

The recommendations in the chapter “A Health-Promoting Diet” are appropriate for BPH. It is particularly important to avoid pesticide residues on fruits and vegetables, increase consumption of fruits and vegetables,9,10 increase the intake of zinc and essential fatty acids, decrease coffee consumption,11 decrease butter consumption, and avoid margarine and other sources of trans fats.911 It is also important to keep blood cholesterol levels below 200 mg/dl.


Paramount in an effective BPH treatment plan is adequate zinc intake and absorption. Studies done in the 1970s showed that zinc supplementation reduces the size of the prostate and decreases symptoms in the majority of patients.12,13 The clinical efficacy of zinc is probably due to its critical involvement in many aspects of androgen metabolism. Intestinal absorption of zinc is impaired by estrogens but enhanced by androgens. Because estrogen levels are increased in men with BPH, zinc uptake may be low.

Studies have demonstrated that zinc inhibits the activity of the enzyme that converts testosterone to DHT.1418 Zinc also inhibits the binding of androgens to androgen receptors in the cell.14

Zinc has been shown to inhibit prolactin secretion by the pituitary gland.19,20 Prolactin increases the uptake of testosterone by the prostate, thereby leading to increased levels of DHT.20 Drugs that block prolactin have been shown to reduce many of the symptoms of prostatic hyperplasia. However, these drugs have severe side effects and are of limited value.21 Beer (but not pure alcohol), tryptophan, and stress all increase prolactin secretion and may therefore be aggravating factors.22,23

The authors of one study of 184 patients and 356 controls reported a positive association between zinc and BPH. A possible reason for this result is that in this study higher zinc may have been associated with intake of meat, a known risk factor for increased BPH.24 It appears that a high meat intake can cancel out the positive effects of zinc against BPH.


Although only beer raises prolactin levels, higher alcohol intake may be associated with BPH. In a 17-year study of 6,581 men in Hawaii, it was noted that an alcohol intake of at least 25 fl oz a month was directly correlated with the diagnosis of BPH.25 The association was most significant for beer, wine, and sake and less for distilled spirits. A smaller study of 889 men described an inverse association between alcohol intake and men treated surgically for BPH or in “watchful waiting” for surgical intervention. In other words, the higher the alcohol intake, the more likely it was that men experienced more severe BPH.

Amino Acids

The combination of glycine, alanine, and glutamic acid has been shown in several studies to relieve many BPH symptoms. In a controlled study of 45 men, increased nighttime urinary frequency was relieved or reduced in 95%, urgency reduced in 81%, daytime urinary frequency reduced in 73%, and delayed urination alleviated in 70%.26 These results have also been reported in other controlled studies.27 The mechanism of action is unknown but is probably related to the amino acids acting as inhibitory neurotransmitters and reducing the feelings of a full bladder. In other words, amino acid therapy is effective only at reducing symptoms.


Toxic cholesterol metabolites are irritating to the bladder. They have been shown to accumulate in an enlarged prostate or in one with cancer. Cholesterol that has been damaged by free radicals can in turn damage prostate cells, leading to the increased cell growth seen in BPH. Every effort should be made to decrease cholesterol levels by using the principles outlined in the chapter “High Cholesterol and/or Triglycerides,” as well as to prevent the formation of toxic forms by maintaining a high intake of dietary antioxidants.

Soy Products

Soybeans are especially rich in phytosterols, especially beta-sitosterol. The cholesterol-lowering effects of phytosterols are well documented.28 Phytosterols have also been shown to improve BPH. A recent double-blind study consisted of 200 men receiving beta-sitosterol (20 mg) or placebo three times per day.29 The beta-sitosterol produced an increase in urine flow rate and a decrease in the urine left behind in the bladder after voiding. No changes were observed in the placebo group. A 3.5-oz serving of soybeans, tofu, or other soy food provides approximately 90 mg beta-sitosterol. Increased consumption of soy and soy foods is also associated with a decrease in the risk of prostate cancer (see the chapter “Prostate Cancer [Prevention]”).

Botanical Medicines

Plant-based medicines are much more popular prescriptions in Europe for BPH than their synthetic counterparts. Specifically, in Germany and Austria botanical medicines are considered first-line treatments for BPH and account for more than 90% of all drugs in the medical management of BPH. In Italy plant extracts account for roughly 50% of all medications prescribed for BPH, while alpha-blockers and 5-alpha-reductase inhibitors account for only 5.1% and 4.8%, respectively.30

About 30 plant-based compounds are currently available in Europe for the treatment of BPH. At least 15 of them contain saw palmetto (Serenoa repens) extract. Other popular botanical medicines include pygeum (Pygeum africanum), stinging nettle (Urtica dioica), and Cernilton, a special flower pollen extract. On the basis of careful examination of the published literature, we rate saw palmetto as the most effective, followed by Cernilton, pygeum, and stinging nettle. However, each plant has a slightly different mechanism of action, and one herb may work better for a particular person than another herb. Combinations may also prove to be more effective than any single agent.

The chance of clinical success with any of the botanical treatments of BPH appears to be determined by the degree of obstruction, as indicated by residual urine content (urine left in the bladder after urination). For levels less than 50 ml, the results are usually excellent. For levels between 50 and 100 ml, the results are usually quite good. Residual urine levels between 100 and 150 ml will make it tougher to see significant improvements. If the residual urine content is greater than 150 ml, saw palmetto extract and other botanical medicines are unlikely to produce any significant improvement on their own.


Over the years many of us in the natural health field have seen the media disseminate questionable results from research studies in major medical journals, holding them up as “proof” that the public is being duped into spending money on worthless natural products. Of course, those knowledgeable about the merits of these same natural products try to mobilize the resources that we have available to counteract these negative statements, but this is often difficult when we are up against an article published in a respected journal such as the New England Journal of MedicineLancetBritish Medical Journal, or Journal of the American Medical Association. Such journals are seemingly more credible than even the natural product industry’s most reputable organizations, companies, and experts.

To illustrate this point, let’s take a quick look at a double-blind study that the media presented as evidence that saw palmetto extract does not work in relieving the symptoms of benign prostatic hyperplasia (BPH). The study was published in the New England Journal of Medicine.35 The news releases that ensued included the Associated Press reporting that a “popular herbal pill used by millions of men doesn’t reduce the frequent urge to go to the bathroom or other annoying symptoms of an enlarged prostate.” That is not true at all. We have been writing about the benefits of saw palmetto extract in the treatment of BPH for over 20 years. We have always pointed out that the success of saw palmetto extract is most obvious in the early stages of BPH. The problem is that the study that got a lot of publicity was done in men with severe, advanced disease, in which saw palmetto is already known not to work. The media did not make this distinction, simply asserting that saw palmetto does not work.

What the media should have reported is that the study reinforced the importance of taking saw palmetto extract early in the disease process, as soon as symptoms of BPH appear (e.g., increased urinary frequency, urgency, increased nighttime urination, difficulty beginning to urinate, urine stream starts and stops, and slow urine flow). If a man waits until his prostate has enlarged so severely that it results in significant obstruction of the bladder, saw palmetto is simply not likely to work. But if he starts it early enough, it is as effective as or more effective than popular prescription drugs without the side effects.


Saw Palmetto

The fat-soluble extract of the fruit of the saw palmetto tree (Serenoa repens), native to Florida, has been shown to significantly diminish the signs and symptoms of BPH. The mechanism of action is related to inhibition of DHT binding to cellular receptors, inhibition of the enzyme 5-alpha-reductase, and interfering with prostate estrogen receptors. Excellent results have been produced in numerous clinical studies, with roughly 90% of men who have mild to moderate BPH experiencing some improvement in symptoms during the first four to six weeks of therapy with saw palmetto extract.3134 As a matter of fact, men treated with saw palmetto had results comparable to those seen by men taking finasteride (Proscar). Adverse effects from the saw palmetto extract were mild and infrequent, with erectile dysfunction appearing more frequently with finasteride (4.9%) than with saw palmetto (1.1%).31 In general, saw palmetto is well tolerated, and it has no known drug interactions.34 One possible side effect is gastrointestinal distress, which is mild and is easily remedied by taking saw palmetto with food. Future studies will hopefully include head-to-head trials comparing saw palmetto with alpha-blockers such as tamsulosin (Flomax), doxazosin (Cardura), and prazosin (Minipress).


Cernilton, an extract of rye-grass flower pollen, has been used to treat prostatitis and BPH in Europe for more than 40 years.36 It has been shown to be quite effective in several double-blind clinical studies in the treatment of BPH.37,38 The overall success rate in patients with BPH is about 70%.37 Patients who respond typically have reductions of around 70% in both nighttime and daytime urinary frequency, as well as significant reductions in urine that is left behind in the bladder after urination.38 The extract has been shown to exert some anti-inflammatory action and produce a contractile effect on the bladder while simultaneously relaxing the urethra. In addition, Cernilton contains a substance that inhibits the growth of prostate cells.39

In one study, the efficacy of Cernilton in the treatment of symptomatic BPH was examined over a one-year period.36 Seventy-nine men averaging 68 years of age (range 62 to 89) were given 63 mg Cernilton twice per day for 12 weeks. They saw improvements in average urine maximum flow rate, average flow rate, and residual urine volume. Overall, 85% of the test subjects experienced benefit: 11% reporting “excellent,” 39% reporting “good,” 35% reporting “satisfactory,” and 15% reporting “poor” as a description of their outcome.



• More than 50% of men will develop an enlarged prostate in their lifetime.

• BPH is largely the result of hormonal changes associated with aging.

• Obesity is a major risk factor for BPH.

• Paramount to an effective BPH treatment plan is adequate zinc intake and absorption.

• Cholesterol damaged by free radicals is particularly toxic and carcinogenic to the prostate.

• Increased consumption of soy and soy foods is associated with a decrease in the risk of getting prostate cancer and may help in treating BPH.

• In Europe, plant-based medicines are the most popular prescriptions for BPH.

• Saw palmetto extract and other herbal approaches to BPH are most effective in mild to moderate cases. Saw palmetto is not likely to be effective in severe cases.

• Roughly 90% of men with mild to moderate BPH experience some improvement in symptoms during the first four to six weeks after beginning to take saw palmetto extract.

• Pygeum, a flower pollen extract (Cernilton), and stinging nettle root extract all have shown excellent results in improving BPH symptoms in double-blind studies.

A summary review of two placebo-controlled studies, two comparative trials (both lasting 12 to 24 weeks), and three double-blind studies of 444 men showed that although Cernilton did not improve urinary flow rates, residual volume, or prostate size, it did improve self-rated urinary symptom scores and reduced nighttime urinary frequency compared with a placebo and an amino acid mixture.40 Clearly, more long-term studies of Cernilton need to be conducted in order to elucidate the terms of its usefulness as an alternative or adjunct to saw palmetto.


The bark of Pygeum africanum, an evergreen tree native to Africa, has historically been used in the treatment of urinary tract disorders. The major active components of the bark are fat-soluble sterols and fatty acids. Virtually all of the research on pygeum has featured an extract standardized to contain 14% triterpenes, including beta-sitosterol and 0.5% n-docosanol. This extract has been extensively studied in both experimental animal studies and clinical trials with humans. A study on rat prostatic cells suggests that the therapeutic effect of pygeum may be due in part to the inhibition of growth factors (e.g., EGF, bFGF, and IGF-I) that are responsible for the prostatic overgrowth.41

Numerous clinical trials with more than 600 patients have demonstrated pygeum extract to be effective in reducing the symptoms and clinical signs of BPH, especially in early cases.41 However, in a double-blind study that compared pygeum extract with the extract of saw palmetto, the saw palmetto produced a greater reduction of symptoms and was better tolerated.42 In addition, the effects on urine flow rate and residual urine content are better in the clinical studies with saw palmetto. However, there may be circumstances where pygeum is more effective than saw palmetto. For example, saw palmetto has not been shown to produce some of the effects on prostate secretion that pygeum has. Of course, as the two extracts have somewhat overlapping mechanisms of actions, they can be used in combination.

Stinging Nettle

Extracts of the root of stinging nettle (Urtica dioica) have also been shown to be effective in the treatment of BPH. Fewer studies have been done with stinging nettle root extract than with the other botanical medicines discussed. Two double-blind studies have shown it to be more effective than a placebo.43,44 However, like pygeum, the results with stinging nettle are less impressive than those with saw palmetto extract or Cernilton. A randomized, multicenter, double-blind study of 431 patients using both the extracts of saw palmetto and stinging nettle found clinical benefit equal to that of finasteride.45 Like the extract of saw palmetto, stinging nettle extract appears to interact with binding of DHT to cellular and nuclear receptors.46 Test tube studies show that stinging nettle root extract may also modulate hormonal effects.47



Therapeutic goals for BPH are to normalize prostate nutrient levels, inhibit excessive conversion of testosterone to DHT, inhibit DHT receptor binding, and limit prolactin, which promotes prostate cell growth.

Severe BPH, resulting in significant acute urinary retention, may require catheterization for relief; a sufficiently advanced case may not respond rapidly enough to therapy and may require the short-term use of an alpha-1 antagonist drug (e.g., Flomax, Cardura, Hytrin, Uroxatral) or surgical intervention.


Exercise is protective against BPH. Follow the recommendations in the chapter “A Health-Promoting Lifestyle.”


The recommendations in the chapter “A Health-Promoting Diet” are appropriate in BPH. It is important to limit the consumption of meat and other animal products; alcohol and coffee; drug-, pesticide-, and hormone-contaminated foods; and cholesterol-rich foods. Soy foods should be consumed regularly.

Nutritional Supplements

• A high-potency multiple vitamin and mineral formula as described in the chapter “Supplementary Measures”

• Zinc: 30 to 45 mg per day (picolinate form preferred)

• Fish oils: 1,000 mg EPA + DHA

• One of the following:

  images Grape seed extract (>95% procyanidolic oligomers): 150 to 300 mg per day

  images Pine bark extract (>90% procyanidolic oligomers): 150 to 300 mg per day

  images Some other flavonoid-rich extract with a similar flavonoid content, super greens formula, or another plant-based antioxidant that can provide an oxygen radical absorption capacity (ORAC) of 3,000 to 6,000 units or more per day

• Specialty supplements:

  images Glycine: 200 mg per day

  images Glutamic acid: 200 mg per day

  images Alanine: 200 mg per day

  images Beta-sitosterol: 60 to 100 mg per day

Botanical Medicines

• One or more of the following:

  images Saw palmetto extract (standardized at 85% to 95% fatty acids and sterols): 320 to 640 mg per day

  images Flower pollen extract (e.g., Cernilton): 63 mg two to three times per day

  images Pygeum extract (14% triterpene content): 50 to 100 mg per day

  images Stinging nettle root extract: 120 to 150 mg twice per day