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Read the USRF study (requires Adobe Acrobat Reader)
First US randomized trial
Marks, LS, Partin, AW, Epstein, JI, et al.
Journal of Urology 2000 May; 163 (5), 1451-1456.

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Your health September 2000

Herbal Rx for prostate problems
Saw-palmetto pills may help--if they contain enough of the right stuff.

Saw palmetto, a traditional herbal remedy, began its modern comeback in alternative-medicine circles in the early 1990s. Word-of-mouth, marketing, and news of mostly European research showing saw palmetto's benefits have made it one of the top ten best-selling herbal remedies, with sales reaching $140 million in 1999. The remedy is used to treat benign prostate problems, which affect 25 percent of men in their 50s and half of men over age 75. In a recent Consumer Reports survey, more than a third of men with such prostate problems had tried saw palmetto.

Clinical testing has now begun to catch up with saw palmetto's popularity. Results show that early 20th-century physicians were onto something when they used infusions and potions made from the fruit of the southeastern U.S. palm plant for male genital and urinary problems.

Saw palmetto has had an off-and-on relationship with official listings of plant and pharmaceutical medicines by the United States Pharmacopeia (USP) and its National Formulary (NF). The berry was included as a medicine for prostate problems in the first half of the 20th century, dropped by the 1950s, and reinstated just this year. An April 2000 USP monograph concluded that clinical trials of saw palmetto "provide evidence of moderate scientific quality that commercial extracts of saw palmetto ... are more effective than a placebo in relieving lower-urinary-tract symptoms of BPH [benign prostatic hyperplasia, or noncancerous enlargement of the gland]." The report also found that the herbal remedy has no significant side effects and only rarely causes mild stomach upset or diarrhea. (However, it noted that drug interactions and medical contraindications have not yet been studied adequately.)

Now that the report has been published, manufacturers who voluntarily meet USP's standards of potency and purity may place the USP's "NF" seal on their labels.

But unlike modern pharmaceuticals, made with chemicals in a lab, plant-based medicines are notoriously difficult to standardize. Individual plants can vary greatly in their content of key active chemicals. And consumers have virtually no protection against inaccurate labeling or substandard preparation, because of a lack of meaningful government regulation of herbal products.

For that reason, Consumers Union is expanding its herbal-testing program. Over the next few years, working with outside labs that specialize in testing herbal products, we will test representative brands of herbal remedies that are performing well in clinical trials. Our ingredient testing will follow our usual standards, which include anonymous shopping at a variety of retail outlets and, for many products, the testing of several samples of each brand, obtained from different parts of the country.

Of the 13 saw-palmetto brands tested for this report, we found that only 8 had the right amount of the right stuff: The number of pills recommended on the label did supply the desirable amount of berry extract, at prices ranging from 44 cents to $1.44 a day. The other 5 brands fell short--often woefully short, with the recommended pills supplying as little as 1 percent of the desirable daily dosage (see What the brands contain).

A pressing problem

Located at the base of the bladder, the prostate gland produces most of the fluid in semen. Normally it's the size of a walnut. But over the years the cumulative effect of the male hormone dihydrotestosterone (DHT) tends to make the gland grow larger, by an average of 175 percent. As a result, it may start to constrict the urethra (the tube that runs through the prostate and carries urine out of the bladder), thereby interrupting normal urine flow. In addition, muscle tone in or near the prostate tends to gradually increase with age; that may eventually trigger recurrent muscle spasms that can restrict the flow of urine. Both processes prevent complete emptying of the bladder, resulting in a frequent, urgent need to urinate, often in the middle of the night; spasms can interrupt the stream as well and sometimes even stop it entirely.

BPH is generally not a dangerous condition, but individuals bothered by any of those urinary symptoms should see a doctor to rule out other diseases such as diabetes, prostate or bladder infection, neurologic disorders, and cancer. If the problem is BPH, a doctor can help you decide whether to treat it, and if so, how.

BPH sometimes improves spontaneously. The decision on what to do--watchful waiting or treatment with saw palmetto, prescription medicine, or surgery--should be driven by how bothersome your symptoms are. If the problem is mild, watchful waiting may be all you need. That means seeing the doctor for regular checkups and taking such steps as limiting evening intake of fluids, particularly alcohol and coffee. Make sure to ask the doctor whether any drugs you're taking--especially diuretics (water pills), antihistamines, decongestants, antidepressants, and tranquilizers--might be aggravating the problem.

However, men whose sleep is continually disrupted by the frequent need to urinate at night or whose lifestyle is circumscribed by having to stay within dashing distance of a bathroom should consider treatment.

Herbal therapy

Researchers aren't sure how saw palmetto works, although they have isolated numerous substances, including certain fatty acids, that appear to be active. Some lab studies suggest that the herbal remedy may have a weak antihormonal effect (too weak to blunt the sex drive or cause feminizing changes); others suggest that it may inhibit the proliferation of prostate cells or help fight inflammation. One recent study did find that saw palmetto decreased prostate size, although several other studies found no such effect.

Most clinical trials have tested saw palmetto against a placebo, not against a prescription drug. In 1998 the Journal of the American Medical Association published a review of 18 such clinical trials. The review, by researchers at the Minneapolis VA Medical Center and other institutions, concluded that the evidence points in saw palmetto's favor. Overall, about three-quarters of BPH patients taking the herb reported an improvement in symptoms, compared with about half of those on placebo. (Such a strong placebo response is not uncommon in clinical trials, particularly if the disorder waxes and wanes.) Moreover, saw palmetto appears to relieve several types of symptoms: It boosted the strength of the urine stream, allowed more-complete emptying of the bladder, and reduced the number of nighttime trips to the bathroom. Those benefits added up to a 37 percent improvement in urinary symptoms.

In the world of herbal medicines, where research is usually scanty, that evidence is rather impressive. But it still falls short of what's usually required for drug approval by the Food and Drug Administration (FDA). The clinical trials have typically lasted only six months or less, while prescription prostate drugs have proved their safety and efficacy in studies lasting up to six years. The American Urological Association (AUA), which represents urologists, says it's keeping an open mind while awaiting the outcome of longer clinical trials, including a one-year placebo-controlled study of saw palmetto funded by the National Institutes of Health.

"What worries me is that we don't know about drug interactions," says H. Logan Holtgrewe, M.D., chairman of the AUA's health-care policy committee. In contrast, he says, "we have two families of medications that have been shown efficacious based on good evidence from prospective, randomized, blinded clinical trials."

As good as a drug?

Saw palmetto costs about $15 to $45 per month (usually not covered by insurance), compared with about $85 for finasteride (Proscar) and $45 to $75 for an alpha-blocker such as doxazosin (Cardura), terazosin (Hytrin), or tamsulosin (Flomax). A recent survey found that some 85 percent of urologists would treat moderate prostate problems with one or more of those prescription drugs, whose combined sales approached $1 billion last year.

The evidence points in saw palmetto's favor.

Finasteride shrinks the prostate by decreasing production of DHT. It works best in the minority of patients with BPH whose gland is greatly enlarged. Few studies have compared finasteride with saw palmetto. But in one six-month trial of more than 1,000 BPH patients, the drug increased urinary flow by 30 percent, while the herbal remedy boosted flow by a comparable 25 percent. What's more, the herbal did not cause the most troublesome side effect of finasteride: erectile dysfunction in about 9 percent of men. And unlike the drug, saw palmetto doesn't interfere with the standard prostate specific antigen (PSA) cancer-screening test. However, the study was too short to draw definite conclusions, since saw palmetto's effects typically kick in within one to two months, whereas finasteride's sometimes take more than six months.

"I think most physicians feel that finasteride's main role in the treatment of BPH is the long-term prevention of complications, such as complete bladder blockage, and of progression to surgery," says Michael Barry, MD, chief of the general medicine unit at Massachusetts General Hospital in Boston. "There's no evidence that saw palmetto conveys that benefit."

Something faster

The other first-line drug treatment for BPH symptoms is an alpha-blocker. Rather than shrinking the prostate, alpha-blockers ease muscle spasms in the prostate and the bladder neck, thus easing constriction of the urethra.

In clinical trials, alpha-blockers have reduced symptoms faster and better than finasteride, although we could find no published data on whether they prevent long-term complications. One published study found that saw palmetto relieved symptoms almost as effectively as an alpha-blocker, but the USP's reviewers concluded that the study was too loosely designed to draw reliable conclusions.

In the recent Consumer Reports survey, readers with benign prostate problems rated prescription medications, presumably including alpha-blockers, more effective than saw palmetto. As our tests suggest, however, some of those readers probably took pills that supplied relatively small doses of saw palmetto.

Overall, a few points do seem clear. Alpha-blockers work faster than saw palmetto, starting to relieve symptoms in as little as one week. But alpha-blockers, particularly doxazosin and terazosin, can cause reduced blood pressure, necessitating careful monitoring with frequent blood-pressure checks.

While some doctors are starting to recommend saw palmetto for patients with mild symptoms--or at least not flinch when patients want to try it--others are unenthusiastic. Claus Roehrborn, M.D., an associate professor of urology at the University of Texas Southwestern Medical Center in Dallas, considers saw palmetto "nothing but junk food." That's because the FDA regulates herbals as foods, not drugs.

Physicians might be more inclined to recommend the herbal medicine if they could be assured that the pills contain the known or probable active ingredients in the amount shown to work in well-designed studies and that the labeled dosages were accurate and appropriate. But as our tests of saw palmetto show, some herbal products may still contain far too little of the apparently active ingredient.


Although the long-term safety and efficacy of saw palmetto remain unclear, Consumers Union's medical consultants say there's enough evidence to conclude that supplements containing at least 320 milligrams per day of saw-palmetto extract, the amount that worked in clinical trials, might be worth trying for some men with mild symptoms; they should discuss that option with their doctor. If symptoms don't improve after two months of taking the remedy, it's probably time to try another approach.

As our tests indicate, makers of some saw-palmetto products need to do a better job of producing standardized, properly labeled products. And the FDA should act on its promise to define good manufacturing practices for nutritional supplements.

Men with troublesome BPH symptoms that don't respond to evening fluid restriction, drug-regimen changes, and possibly saw palmetto should turn to prescription prostate medication. Because alpha-blockers work so rapidly, they're usually worth trying before finasteride, especially for men with intermittent urinary flow and no more than moderate prostate enlargement. If alpha-blockers don't work, doctors can prescribe finasteride for men with a very large prostate. If all else fails, paring down the prostate via surgery or one of several other invasive techniques can be considered. The latest and best study suggests that those methods do not increase the risks of incontinence or impotence, although some may cause infertility.

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