Saw Palmetto Safety

Saw palmetto appears to be safe in the treatment of enlarged prostates, a new study reports.

Researchers from Northern California Kaiser Permanente explained that saw palmetto is commonly used by men for lower-urinary tract symptoms. Despite its widespread use, very little is known about the potential toxicity of this dietary supplement.

The Saw palmetto for Treatment of Enlarged Prostates (STEP) study was performed among 225 men with moderate-to-severe symptoms of benign prostatic hyperplasia (enlarged prostate). Researchers compared a standardized extract of the saw palmetto berry (160 milligrams twice daily) with a placebo over a one-year period.

The researchers collected detailed data on serious and non-serious adverse events, sexual functioning and laboratory tests of blood and urine. Between-group differences were assessed with mixed-effects regression models.

The study found no significant differences between the saw palmetto and placebo-allocated participants in the risk of suffering at least one serious adverse event (5.4 percent vs. 9.7 percent, respectively) or non-serious symptomatic adverse event (34.8 percent vs. 30.1 percent).

The study also found few significant between-group differences in sexual functioning or for most laboratory analyses, with only small differences observed in changes over time in total bilirubin, potassium and the incidence of glycosuria or sugar in the urine (0 percent in the saw palmetto group vs. 3.7 percent in the placebo group).

The study authors concluded that after careful assessment, no evidence for serious toxicity of saw palmetto was observed. However, the authors recognized the small sample size and length of the study and suggested that the data do not rule out potential rare adverse effects associated with the use of saw palmetto.

Comments

[Kip]

Saw palmetto is widely used in the United States. A 2006 report stated that more than two million men in the United States use saw palmetto for the treatment of benign prostatic hyperplasia (BPH), and it is commonly recommended as an alternative to conventional drugs approved by the U.S. Food and Drug Administration (FDA). It's good to know that studies are being done to confirm its safety.

[Matt]

It surprises me that multiple safety studies on saw palmetto haven't been done already. Saw palmetto has been studied extensively for the treatment of benign prostatic hypertrophy (BPH) and has been approved by the German expert panel, the Commission E, for the treatment of mild-to-moderate BPH ("stage I-II"). In Italy, herbal therapy represents approximately half of treatment for BPH, whereas in Germany and Austria, it is a first line treatment. I always assumed its safety was proved because it's considered a standard form of treatment in some places.

[Sue]

There have been at least two case reports of clinically significant bleeding associated with saw palmetto products. So, you should be careful if you take anticoagulant medications, such as warfarin.

[Barney]

I have to applaud the researchers for trying to establish the safety of saw palmetto, but even they point out the results fall short. From the stand point of a clinician, this trial could be compared to a phase-2 pharmaceutical trial, in which side effects are further explored, but the safe and effective dose has been previously determined in other trials. This STEP study is using 160mg twice a day as a dose because they know it has been shown to be effective and safe, as shown in previous studies. If the researchers really wanted to determine if saw palmetto is safe, they would have gradually increased the dose from 160mg twice daily to a much higher dose. Like the study authors indicated, this dose of saw palmetto may have no serious adverse effects, but what about long-term or rare side effects?

[Lacey]

I agree with you Barney. The dose should have been increased, or they should have at least studied doses that are commonly used. the German expert panel, the Commission E recommends 320mg daily in one dose or two divided doses (80-90% liposterolic content)for the treatment of BPH.

[Billy]

Was the extract given orally? Rectal administration of saw palmetto (640mg once daily) extract has also been studied in clinical trials.

Also, it's worth mentioning that saw palmetto may theoretically lower prostate specific antigen (PSA) levels. PSA is a marker for prostate cancer and other prostate disorders. Therefore, saw palmetto may delay diagnosis in patients with prostate conditions.

[LM]

I was a little surprised to read about this study because I also believed that saw palmetto has already been proved to be safe and effective since it has been used for benign prostatic hyperplasia (BPH) for years. It would be interesting to know how this herb compares to conventional medication therapy, such as tamsulosin (Flomax®), in the treatment of BPH.

[DC]

I wonder how many physicians currently would feel comfortable recommending saw palmetto instead of tamsulosin? It is certainly nice data to see though. Maybe saw palmetto is on the fast track to reaching omega-3 PUFAs (fish oil) in the class of "most medicinally accepted herbal medicines." Now, if the other innumerable amount out there would get some further credit...

[mo]

I always find it interesting that we assume something is safe just because it is freely available. This forum is obviously frequented by people who are knowledgeable about dietary supplements and still there are misconceptions.

There are other options available for natural approaches to an enlarged prostate, including beta-sitosterol and pygeum. Beta-sitosterol is found in plant-based foods, such as fruits, vegetables, soybeans, breads, peanuts and peanut products. It is also found in bourbon and oils, (like olive oil, flaxseed and tuna). The P. africanum (African plum) tree is a tall evergreen of the Rosaceae family. It is found in central and southern Africa. Its bark has been used medicinally for thousands of years. Traditional African healers have used the bark to treat bladder and urination disorders, particularly symptoms associated with benign prostatic hypertrophy (enlarged prostate).

[Bella]

Pygeum has been shown to moderately improve urinary symptoms associated with an enlarged prostate. In studies, it significantly reduced the number of nighttime urinary episodes, urinary hesitancy, urinary frequency and dysuria in men who experienced mild-to-moderate symptoms.

However, pygeum does not appear to reduce the size of the prostate gland or reverse the process of BPH. It is unclear how pygeum compares to the effectiveness or safety of other medical therapies, surgical approaches or herbs/supplements (such as saw palmetto).

Examples of studied brands include Pigenil® (Inverni della Beffa, Milan, Italy), Harzol® (Hoyer, Germany), and Prostatonin® (Pharmaton SA, Lugano, Switzerland).

[Allie]

Active agents within saw palmetto may be sterols and fatty acids, such as myristoleic acid. The exact mechanism of action is unknown.

Saw palmetto has been shown to inhibit 5-α-reductase activity on testosterone in vitro, thereby preventing the conversion of testosterone to dihydrotestosterone (DHT) and possibly exerting an antitumor effect. However, evidence of 5-α-reductase inhibition from randomized trials is conflicting. A modest but significant decline in prostatic DHT levels was observed in a six-month placebo controlled trial involving 40 men. In one study, researchers noted a decrease in epidermal growth factor, which they associated with DHT suppression in prostatic tissue of patients treated with saw palmetto (Permixon®). However, an open, randomized, placebo-controlled study indicated that Permixon® may not reduce plasma DHT levels, although this study was limited by its short (one-week) duration. A six-month controlled trial of saw palmetto in 41 men from whom prostate biopsy specimens were obtained revealed significant contraction of transition zone epithelium and epithelial atrophy. The authors suggested that since no evidence of alteration in prostatic androgen metabolism was demonstrated, saw palmetto may suppress prostatic epithelium via a non-hormonal mechanism.

Clinical observations have suggested a lack of systemic hormonal effects, including unchanged levels of testosterone, follicle-stimulating hormone, and luteinizing hormone. Possible estrogenic effects of saw palmetto have been suggested to derive from β-sitosterol, although subsequent evaluation reports possible inhibitory effects on estrogen receptor binding.

[Chelsea]

I just learned some interesting facts about saw palmetto:

The tannins that may be present in saw palmetto may prevent the body from properly absorbing iron.

Teas prepared from saw palmetto berries are potentially ineffective because the active constituents are water insoluble.

[Jodi]

The American Herbal Products Association rates saw palmetto as a class 1 herb. This means it is considered safe when taken as recommended.

I've also heard of people using saw palmetto to treat hirsutism and polycystic ovarian disease. However, I'm not sure how strong the evidence is for these uses.

[Levitte]

In general, how long do people have to take saw palmetto to treat BPH? I'm wondering if a year is the average length of time people usually take it.

I've heard that it takes about 30 days for it to start taking effect. Is this true? Has anyone tried it before?

[Larry]

In response to Levitte’s comment, some studies that have reported positive effects were only 1-6 months in duration. However, there is currently no definitive answer to the question. Most medications require that the blood concentration reaches a steady state that is considered therapeutic. This could take 29 days or 290 days for saw palmetto and has yet to be studied. Any claims that it works after 30 days may be word of mouth at best.

[Cindy]

Stinging nettle is used rather frequently in Europe to treat the symptoms associated with benign prostatic hyperplasia (enlarged prostate). Early evidence suggests that stinging nettle may help improve symptoms associated with stage I or II BPH. Additional study is warranted in this area.

[Jill]

Benign prostatic hyperplasia (BPH) is a normal, gradual enlargement of the prostate caused by hormonal changes, such as decreases in testosterone and increases in dihydrotestosterone (DHT) and estrogen in prostate tissue. The prostate gland, which is located in front of the rectum and under the bladder, is part of a man's reproductive system. It surrounds the urethra, the tube that carries urine. A healthy prostate is about the size of a walnut.

BPH usually beings in middle age. It is called “benign” because the condition does not lead to cancer.

BPH does not generally cause pain, but discomfort, or a feeling of pressure, in the groin area is generally found. As the prostate enlarges, it presses against the urethra and interferes with urination. At the same time, the bladder wall becomes thicker and irritated and begins to contract, even when it contains small amounts of urine, which causes more frequent urination. And, as the bladder continues to weaken, it may not empty completely leaving some urine behind.

[Jake]

BPH affects about half of men who are 60 or older and 80% of men who are 80 or older. It is considered to be related to aging because most men older than 45 have some prostate enlargement. However, symptoms are rarely felt before the age of 60.

[Leah Cohen]

To confirm Kip's comment above, saw palmetto has been approved by the German Commission E for: "Urination problems in benign prostatic hyperplasia stages I and II." The side effects mentioned by the German Commission E are "In rare cases, stomach problems." The dose recommended by the Commission E is: 1-2 grams of saw palmetto berries or 320 milligrams of lipophilic ingredients extracted with lipophilic solvents (hexane or ethanol 90 percent v/v).