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Frequently Asked Questions about Saw Palmetto

Answered Dr. Arnaldo F. Trabucco


Q. I am not sure what your final conclusion is?

A. Summary: Self medication for prostate disorders has increased throughout the US and the rest of the world. Saw palmetto extract (SPE) in particular raises concerns for urologists regarding their ability to diagnose and treat prostate cancer. In regard to its potential lowering effect on the prostate specific antigen (PSA) and masking prostate cancer detection.

Q. Is it true that many doctors feel that prostate cancer may not be clinically significant when diagnosed?

A. This is true depending on the age group it is detected in, the type of cancer and the stage at presentation! However prostate cancer is the most commonly diagnosed cancer in American men. In 1996, the American Cancer Society estimates 317,100 new cases of prostate cancer, and 41,400 deaths from prostate cancer expected, among men in the United States. In other words, 113 men die of the disease every day. It is the second most common cause of death in men older than 55. Early detection is the most important factor for cure! We are detecting prostate cancer within the past decade with increasing frequency, and many patients with this condition are receiving such treatments as radical prostatectomy and radiation therapy for cure. PSA-based testing has contributed substantially to the increased detection rate of prostate cancer, but the incidence of the disease is increasing dramatically yearly.

Q. I've been on saw palmetto for quite some time but never had a PSA. How does saw palmetto affect the PSA ?

A. Research indicates that SPE has an effect on competitively inhibiting the binding of dihydrotestosterone (DHT) and blocking the conversion of testosterone to DHT, via its inhibition of 5-alpha reductase. It is known that 5-alpha reductase inhibitors will reduce the PSA levels by average of 50% after 6-12 months. There are no "well done" double- blind, "long term" double-blind controlled studies evaluating the effect of SPE on PSA levels. PSA has revolutionized our ability to pick up prostate cancer. Masking the PSA will decrease the clinical detection of diagnosing prostate cancer. Many patients and doctors are unaware of this potential effect of SPE. Further research needs to be done.

Since SPE can act as a 5-alpha reductase inhibitor, thereby potentially interfering with PSA levels in men and decrease prostate cancer detection, it is recommended that men get a baseline PSA level and Digital Rectal Exam with careful qualified medical supervision when using SPE.

Q. Why are you so hung up on the effects of PSA from saw palmetto?

A. Although refinements in PSA-based testing have contributed substantially to the increased detection of early prostate cancer, the incidence of the disease is increasing dramatically although the detection by PSA-incidence is falling since 1992. [12]

Q. Why is this happening?

A. Possibly the confusion in the literature about when to and who to treat prostate cancer has contributed to this decline. Or what to do when the PSA is elevated above 4.0? So has the introduction of medical therapy, neglecting to obtain PSA levels, with 5-alpha reductase inhibitors and herbs (SPE) introduced during the same time period.[11] The most disturbing aspects of self-treatment with such herbal remedies are their potential effects in masking PSA, which has revolutionized our ability to pick up prostate cancer. If one curtails the ability to detect prostate cancer by PSA, many cancers will progress undetected until it is too late, resulting in Stage D Disease.

Q. If saw palmetto can mask PSA does that mean that causes prostate cancer?

A. SPE does not cause prostate cancer. However, any interference with PSA makes this test useless as a diagnostic tool for prostate cancer. The FDA does not regulate the use of SPE (its use falls under the guidelines for food supplements). Many patients are self treating their "urinary difficulty" with SPE, using it without proper medical supervision and an underlying condition, possibly prostate cancer, may be present and masked by losing the sensitivity of the PSA diagnostic test.

Q. Are you stating that if PSA levels are reduced because of the application of saw palmetto that this does not indicate the fact of lower probability of cancer exists. In other words, just because PSA levels have been decreased. the probability of cancer has not?

A. In my own clinical practice, I have seen many patients on SPE who were embarrassed to bring this to my attention as a urologist. I have noticed a drop in PSA levels when patients have been on this herb for many months, making my clinical diagnostic determination of prostate cancer more complex. I have also found many patients on SPE and picked up prostate cancer as the cause of their "urinary difficulty" with normal PSA levels. Any 5-alpha reductase inhibitor--whether saw palmetto or finasteride--will reduce PSA significantly.

Q. If saw palmetto lowers PSA doesn't that mean it is good and can prevent prostate cancer?

A. Recently a 52 year old patient came to me for a simple evaluation for another medical problem and was on this herbal extract for several years, with a family history of prostate cancer. Upon questioning the patient as to why he was taking this herb his response was to prevent prostate cancer. Needless to say I evaluated this individual and found a stage C. Prostate cancer, with a PSA of 3.8 with previous yearly evaluations within the normal range. Many patients have been taking this extract with the belief that it will not only cure their BPH but also with the belief that it may potentially prevent the development of prostate cancer. This is not true!

Q. Lowering the PSA is better for men and can prevent PC, and studies are being done to confirm that is this not true?

A. Although investigations are underway with respect to the effects of 5 alpha reductase inhibitors (Proscar) and its role in future treatment of prostate cancer, these studies are providing experimental research. We will not know these answers for 10 to 15 years from now, due to the natural history of the disease. Presently there is nothing in the literature to substantiate the use of any 5 alpha reductase inhibitor as either a treatment modalities or preventive measures for prostate cancer management. There is no antineoplastic function that has ever been documented by saw palmetto!

Q. Are you saying that PSA decreases in all patients taking SPE?

A. With all the studies completed to date, regarding the effects of saw palmetto on PSA, their are some studies to show the lack of effects of SPE on patients with BPH which have excluded patients with prostate cancer. However, due to the fact that PSA is leached out into the blood stream as a marker in patients with prostate cancer, it is imperative to decipher that up to this point in time, there have been no long term well done double blind controlled studies to show the effects of this SPE herb on PSA "with patients that have prostate cancer." I believe that that this is an important caveat for the end consumer to consider. Unfortunately, many patients take it upon themselves to self treat without consulting a urologist. That is where the main problem lies as I have witnessed anecdotally in my clinical practice.

Q. What is the position of the American Urological Association on saw palmetto?

A. This is a statement that Irwin N. Frank, M.D., F.A.C.S., president, American Urological Association, recently made to United States Food and Drug Administration:

The American Urological Association (AUA) representing 9,500 urologists in the United States appreciates the opportunity to present its views on the issues of food supplements containing saw palmetto. The AUA wishes to emphasize, once again, in the strongest possible terms that lower urinary tract symptoms in older men (urinary frequency, urinary urgency, slowing of the urinary stream, hesitation on initiation of urination and rising at night to void multiple times) are often due to diseases of the genitourinary system. They are usually NOT a normal phenomenon of aging. The AUA is deeply concerned that food supplements containing saw palmetto currently being offered to maintain prostate health, to treat benign prostatic hyperplasia (BPH) or to alleviate lower urinary tract symptoms could be very misleading to the public. Life-threatening cancers (cancer of the prostate and cancer of the urinary bladder) can cause lower urinary tract symptoms. The AUA is concerned that men experiencing such symptoms may self-medicate with food supplements containing saw palmetto, thus, delaying the timely and proper diagnosis of their cancers. The AUA is concerned that the package inserts accompanying these supplements, no matter what admonitions they might contain, are infrequently read by the user or, if read, are ignored or misunderstood.

The AUA is also concerned about the safety of food supplements containing saw palmetto for lower urinary tract symptoms. Most products currently being marketed in the United States for lower urinary tract symptoms and BPH are combinations of multiple ingredients. Each product is often different from the other. The various multiple components could differ within each individual product.

The AUA very strongly believes that each of these products marketed for lower urinary tract symptoms and BPH should be individually tested for safety given that each product could be different. Further, the AUA believes that each product should be tested for possible drug interactions with the wide variety of prescription medications (anti-hypertensives, anti-diabetics, mood-altering drugs, cardiac medications and other pharmacological agents), which are so commonly being taken by older men. Such testing and study could insure that a specific saw palmetto containing food supplement product poses no serious threat of adverse drug reactions when taken with other pharmacological agents. The AUA believes that there currently exists inadequate medical data ruling out possible serious interactions.

In a randomized, placebo-controlled, six-month study of 44 men with lower urinary tract symptoms and an enlarged prostate gland upon digital rectal examination, Marks and coworkers [1] reported no adverse events in his cohort of patients taking the herbal product containing saw palmetto, which was under study. However, an entry criteria into the study was that the men "be in good general and mental health." No data were given about the prescription medications those men on the herbal compound containing saw palmetto might have been taking at the time of the study. Thus, no data regarding prescription drug interaction can be gleaned from this small study since the men in this study were in good health and might not have been taking any such prescription medications.

Our Association believes it is inappropriate to cite the safety data on pure saw palmetto products currently marketed in Europe (such as Permixon not currently available in the United States) as proof of the safety of the mixed products containing saw palmetto being marketed in the United States. Permixon and the United States mixed products containing saw palmetto are not comparable, thus, making safety extrapolations scientifically invalid.

The mission of the American Urological Association through its members is to provide the highest quality of care to patients with genitourinary disease. In pursuit of this mission, the AUA continually maintains an open mind. However, the American Urological Association strongly believes that food supplements containing saw palmetto marketed for the alleviation of lower urinary tract symptoms, the treatment of BPH, and for the maintenance of prostate health should be controlled by the Food and Drug Administration (FDA) and held to the same standard as are all other pharmacological agents intended to treat disease.

The AUA believes that these food supplements containing saw palmetto should be carefully studied through properly controlled, perspective, randomized clinical trials under the auspices of the FDA as are all other pharmacological agents being marketed for disease control. Through such studies, the safety of food supplements containing saw palmetto can be assessed along with any possible drug interactions they might create.

Should proper studies confirm the safety and efficacy of food supplements containing saw palmetto, the AUA would welcome their addition to the armamentarium of American physicians treating men with lower urinary tract symptoms due to benign disease.

The American Urological Association strongly urges the Food and Drug Administration to control food supplements containing saw palmetto marketed to alleviate lower urinary tract symptoms, to treat benign prostatic hyperplasia or to maintain prostatic health. Proper clinical trials can resolve safety and efficacy issues. It is our understanding that the National Institutes of Health is actively considering setting in place clinical trials on saw palmetto and food supplement products in the treatment of lower urinary tract symptoms and benign prostatic hyperplasia. The American Urological Association applauds the concept of such studies and anxiously awaits their outcome.


Last modified: September 3, 2000

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