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Dietetic Internship

Food for Thought

Katie Clay

Foods as Drugs: Saw Palmetto for the Treatment of Benign Prostatic Hyperplasia
As one thinks back on the history of healing, we recognize that in early medicine, healing was the province of priests and the religious (1).  The evolution of healing from the priest to the physician was a sequel of the mind-body split that occurred in the Middle Ages. This separation resulted in 2 very different schools of thought, Western medicine and Eastern medicine.

Historically, Western medicine has been characterized by the unidimensional attempt to find a single answer to the cause of disease.  Its heavy reliance on technology has lead to some spectacular breakthroughs in disease control.  In contrast, Eastern medicine has embraced more holistic techniques in which polytherapy is the rule rather than the exception.  Thus, it is common for Eastern medicine to use nutrition and nutritional supplements, herbology and other nontraditional modalities to heal.

Herbal therapy has been a consideration in the treatment of various diseases since the days of the Old Testament. The book of Ezekiel 47:12 reads, “And on the banks, on both sides of the river, there will grow all kinds of trees. Their fruit will be for food and their leaves for healing.”  Thus, more than 2 millennia ago the recognition that herbal therapy may be beneficial in healing a variety of diseases was evident.

Why should unconventional medicine be important to physicians?  The sale of all botanical medications in the United States [U.S.] exceeds $1.5 billion per year and the use of phytotherapies increased nearly 70% in the past year (2).  In addition, an alarming number of patients are not reporting their use of nutritional and/or herbal supplements to their physician due to feelings of hostility from the physician; noninquiry by the physician; fear of reprisal from the physician; or thinking it is unimportant for the physician to know (3).

Because of the rise in phytotherapeutic self-treatment by patients, it is increasingly important for physicians to be aware of their patients’ alternative practices. Natural remedies and herbal treatments are gaining remarkable popularity among middle-aged persons and senior citizens in the U.S., who are fed-up with conventional Western medicine failing them. Traditional medicine is a “Johnny-Come-Lately” approach focusing on treating/curing disease after it has occurred (4). While many alternative therapies are portrayed as being preventative and for treatment and cure making their use attractive to patients with chronic or incurable diseases.

Benign prostatic hyperplasia [BPH] is one of the most common medical conditions in older men (2).  BPH affects about half of all men in their sixties and as many as 90 percent of men in their seventies and eighties, most of whom may never experience symptoms. However, BPH becomes a medical concern when the prostate grows large enough to pinch the urethra, resulting in urinary difficulties and discomfort (5,6).

As many as 40 percent of men aged 70 years or older experience these lower urinary tract symptoms consistent with BPH (2).  Given the aging U.S. population, by 2020, the number of people over 60 years of age is projected to triple and the prevalence of symptomatic BPH is expected to rise dramatically (5). The prospect of millions of additional BPH cases has intensified the effort to find effective, efficient, and patient-friendly methods of treating the condition. 

It is not uncommon for a patient who consults a urologist for the first time because of moderate symptoms of BPH to already be self-medicating with alternative therapies, such as saw palmetto (7). Treatment of BPH in the U.S. exceeds $2 billion, accounts for 1.7 million physician office visits, and results in more than 300,000 prostatectomies annually (2). Treatment options include lifestyle modification, device and surgical therapies, and pharmaceutical and phytotherapeutic [plant-derived] preparations. Treatment goals in the vast majority of men are to relieve irritative [urgency, frequency, and nocturia] and obstructive [weak stream, hesitancy, intermittency, and incomplete emptying] symptoms.

Patient demands for alternative therapies in the treatment of BPH have created a huge market for herbal preparations. The most frequently used is a sterol extract of the Serenoa repens plant, commonly known as saw palmetto (8). Saw palmetto is a member of the fan palm family with large leaves and deep red berries, native to the southeastern U.S. (9-13).  The benefits of saw palmetto can be traced back 3,500 years to the aborigines of the Florida peninsula who depended largely upon the berries as a subsistence food in the fall, during which time, older men found that they didn’t have to get up so much in the middle of the night to urinate (14-16).

Since then, the partially dried fruits have been used by traditional healers to produce a drug useful in treatment of troubles of the bladder, urethra, and prostate (11,17). The aborigines used the berries to treat a variety of conditions including: testicular atrophy, impotence, low libido in men, infertility in women, prostatic inflammation, urinary tract disorders [nocturia, dysuria], and thyroid deficiency. They were also used to increase lactation and improve digestion, and as an expectorant [for colds, bronchitis, asthma], mild sedative, anti-inflammatory agent, appetite suppressant, and general tonic to nourish the body (13,15). 

The demand for saw palmetto remained low until the 1960s, when it started to expand in Europe (14,16).  Presently, phytotherapy accounts for nearly half the medication dispensed to treat BPH in Italy and greater than 90 percent of all BPH prescriptions in Germany and Austria (2,5).  In 1994, American men rediscovered the berries of the saw palmetto when federal dietary supplement laws were relaxed (14,16).  These supposed restorative powers dating back to Indian lore are making the fruit of saw palmetto into a multimillion-dollar export.  In fact, according to Herbs for Your Health by Steven Foster, saw palmetto is the sixth-best-selling herbal dietary supplement nationwide.

The first scientific observations concerning the therapeutic applications of saw palmetto appeared in the American Journal of Urology in 1892 (11). Since that time, numerous studies have been conducted in an effort to gain understanding of how saw palmetto works (18). A commonly proposed mechanism of action for saw palmetto is the inhibition of 5-alpha-reductase, thereby blocking the conversion of testosterone to dihydrotestosterone [DHT] (13,15,18,19).

If this is the actual pathway, saw palmetto acts in a way similar to prescription alpha-blockers.  Another possible mechanism of action is based on the finding that saw palmetto extract contains at least 2 fractions, 1 with antiandrogenic effects, and the other with antiestrogenic effects.  he latter could block the translocation of estrogen receptors [ER] to the nuclei by competition (20). It cannot be excluded, however, that the primary effect is antiestrogenic and that the inactivation of androgen receptors [AR] and progesterone receptors [PgR] is secondary to ER blockade.  Because of the complex composition of the extract, a multiple mechanism of action seems paramount to its therapeutic activity.

American physicians generally don’t prescribe any drug other than finasteride [Proscarâ], for the treatment of BPH (9).  Finasteride works by blocking the conversion of testosterone to DHT, via its inhibition of 5-alpha-reductase, the same mechanism proposed for saw palmetto (10). Although finasteride has received much attention based on clinical trials, only about one- third of patients experience any clinical improvement after taking the drug for 1 year, and little or no results are evident before at least 6 months of treatment (6,9,10).

A study by McConnell et al demonstrated that, when used for 4 years by symptomatic men with enlarged prostates, finasteride caused a twofold decrease in the need for prostate surgery, a mild decrease in urinary symptoms, and a mild increase in urine flow rates (8). The study also found finasteride to cause occasional erectile dysfunction, decreased libido, and decreased ejaculatory volume. Clinicians agree that the use of finasteride for urinary obstruction is modest and limited to men with palpably larger glands. In a review of 6 double-blind placebo-controlled studies, testing the effectiveness of 320mg/day saw palmetto extract, n=22-168 (total n=400), and ranging from 28 days to 3 months in length, the primary findings were decreased dysuria, nocturia, frequency of urination, and residual urine, and increased urine flow (10).

Figure 1 is based on pooled data on saw palmetto extract from all clinical trials and pooled data on finasteride listed in the Physician’s Desk Reference, comparing their effect on urine flow rate in men with BPH (10).

Saw PalmettoFinasteride
Initial Measurement9.53 ml/sec9.6 ml/sec
3 months13.15 ml/sec10.4 ml/sec
12 monthsNot available11.2 ml/sec
% increase38% in 3 months16% in 12 months

Urine flow rate in males treated with Saw Palmetto v. Finasteride Figure 1

In conclusion, saw palmetto sounds promising in the treatment of BPH.  The clinical research is there to support its effectiveness and safety. The American Medical Association concurs that saw palmetto is effective in the treatment of BPH, stating,  ‘Clearly saw palmetto offers superior symptomatic relief in prostate disease as defined by most common clinical tests.’  In addition, it improves quality of life and has a ‘practically negligible side effect risk’ (2).  Perhaps eventually the Food and Drug Administration will consider herbals for their true medicinal value.  However, at present, American men suffering from symptoms associated with BPH must use saw palmetto as a dietary supplement rather than a prescribed medication.

Of concern, what sets alternative/complementary medicine apart from traditional medicine is that it has not been scientifically tested and its advocates largely deny the need for such testing (21).  By testing, what is meant is the marshaling of rigorous evidence of safety and efficacy, as required by the FDA for the approval of drugs and by the best peer-reviewed journals for the publication of research reports. Thereby making what you read on the label what you are actually getting.

Clinicians are being confronted on almost a daily basis with patients taking herbal and non-herbal preparations, whether they are aware of it or not (4).  It is imperative that physicians have some basic knowledge regarding herbal treatments, even if solid clinical trials and scientific studies are lacking.  Clinicians are in an excellent position to offer advice and discuss the risks and benefits pertaining to herbal treatments, which can aide their patients in making informed decisions about their use.  Some facts to share with patients about herbal preparations/dietary supplements are listed in Table 1.

1) Not all that is natural is harmless.
2) If something is good for health, it doesn’t mean that more is necessarily better: it can be harmful.
3) Medical herbs and supplements may not only have potential benefits, but also the potential to interact with other drugs and cause toxic reactions.
4) Advice given in health food stores can be dangerously misleading.
5) Manufacturers have no regulatory responsibility to ensure safety of their products. There are no requirements for FDA approval.
6) Possibility of contamination, adulteration, and misidentification of plant species may exist.
7) Children and the elderly may be more prone to adverse effects from herbal treatments because of their decreased metabolizing ability.

Alternative therapy facts to share with patients - adapted from Sardesai and Myers (4) Table 1


  1. Fair WR.  Willet F. Whitmore, Jr. Lecture: Back to the future-the role of complementary medicine in urology.  J of Urol 1999;162(2):411-20.
  2. Wilt TJ, Ishani A, Stark G, MacDonald R, Lau J, Mulrow C.  Saw palmetto extracts for treatment of benign prostate hyperplasia: a systematic review.  J Am Med Assoc 1998;280:1604-9.
  3. Nam RK, Fleshner N, Rakovitch E, et al.  Prevalence and patterns of the use of complementary therapies among prostate cancer patients: an epidemiological analysis.  J of Urol 1999 May;161(5):1521-4.
  4. Sardesai VM, Myers T.  Nutrient supplements in clinical care.  Nutr in Clin Pract 2001;16(1):35-45.
  5. Benign prostate hyperplasia: prostate gland enlargement.  Available at:  Accessed:  November 17, 2000.
  6. Phytomedicines outperform synthetics in treating enlarged prostate.  Available at:  Accessed:  November 17, 2000.
  7. Lieber MM. Pharmocologic therapy for prostatism.  Mayo clinic proceedings of symposium on benign prostatic hyperplasia-part I; 1998 June; Rochester, MN: Mayo Foundation for Medical Education and Research. 1998.
  8. Litwin MS. Urology.  J Am Med Assoc 1999;281(6):495-6.
  9. Saw palmetto for benign prostate hyperplasia (BPH).  Available at:  Accessed:  November 17, 2000.
  10. Saw palmetto extract vs. Proscar.  Available at:  Accessed:  November 17, 2000.
  11. Sabalselect.  Available at:  Accessed:  November 17, 2000.
  12. Blurbs on herbs: the potentially beneficial and the toxic.  Available at:  Accessed:  November 17, 2000.
  13. Saw palmetto.  Available at:  Accessed:  November 17, 2000.
  14. Cash crop?  Available at:  Accessed:  November 17, 2000.
  15. Saw palmetto harvesting company’s worldwide website.  Available at:  Accessed:  November 17, 2000.
  16. Supposed powers make saw palmetto berries desirable.  Available at:  Accessed: November 17, 2000.
  17. Commission E monograph on saw palmetto.  Available at:  Accessed:  November 17, 2001.
  18. Sahelian R.  Saw palmett nature’s prostate healer.  New York City: Kensington Publishing Company; 1998.
  19. Saw palmetto warning:  problems with detecting prostate cancer?  Available at:  Accessed:  November 17, 2000.
  20. DeSilverio F.  Evidence that serenoa repens extract displays an antiestrogenic activity in prostatic tissue of benign prostatic hypertrophy patients.  J Eur Urol 1992;24:309-14.
  21. Angell M, Kassirer JP.  Alternative medicine-the risks of untested and unregulated remedies.  New Engl J Med 1998;339(12):839-41.