The saw palmetto controversy
A widely used herb for mild to moderate benign prostatic hyperplasia is in the limelight after a trial published recently suggested that it was no better than a placebo. Is this really the case?
THE latest results of a new clinical trial on the popular herb, saw palmetto, may confuse the public, especially men with prostate problems, according to the American Botanical Council (ABC), a non-profit herb research and education group.
The trial, published in the Feb 2006 issue of the New England Journal of Medicine (NEJM), found no significant differences between saw palmetto pill and a placebo in men with moderate to advanced prostate problems1.
Most of the official international monographs that recognise the benefits of saw palmetto do so for stage 1 and 2 of BPH, the mild to moderate range of benign prostatic hyperplasia symptoms.
Mild to moderate
Saw palmetto is an herbal supplement that is widely known for its safety and efficacy in treating mild to moderate symptoms of benign prostatic hyperplasia (BPH). BPH is a non-cancerous enlargement of the prostate gland, which is common in men over 50 years of age, affecting almost 75% of men in this category.
Symptoms of BPH include weak urine flow, difficulty in starting urination, straining to urinate, dribbling after urination and incomplete emptying of the bladder. Other symptoms include the urgent need to urinate, frequent need to urinate, increased frequency of urination at night and urge incontinence.
Our primary concern with this trial is the relatively advanced conditions of the prostate problems in many of the men who were tested, said Mark Blumenthal, Founder and Executive Director of ABC.
Blumenthal emphasised that the men in this trial experienced moderate to severe symptoms of BPH, although most of the previous controlled trials showing positive results and efficacy for saw palmetto were conducted on men with mild to moderate symptoms of BPH. The men in the trial had scores between 8-35, i.e., moderate to severe BPH, according to the American Urological Association Symptom Inventory (AUASI).
Most of the official international monographs that recognise the benefits of saw palmetto do so for stage 1 and 2 of BPH, i.e., the mild to moderate range of BPH symptoms, said Blumenthal. These include monographs from the German government and the World Health Organization.
The results of this trial need to be seen in the perspective of the preponderance of the existing evidence, including at least 21 controlled trials showing positive outcomes with saw palmetto preparations, he added.
Saw palmetto extracts are widely used in Europe, and in the past decade, in the United States as a natural therapy to help maintain normal prostate and urinary function, particularly by treating the symptoms of BPH in men with mild to moderate cases of BPH.
Over 22 clinical trails carried out in over 3,000 men as reviewed by the Cochrane Collaboration2 have confirmed the safety and efficacy of saw palmetto standardised extract preparations in treating mild to moderate symptoms of BPH.
The latest meta-analysis2 concludes that the clinical literature supports the use of 160mg (twice daily) saw palmetto standardised to contain 85-95% fatty acid extract preparations in mild to moderate symptoms of BPH, and that the saw palmetto standardised extract preparations have shown efficacy and greater safety when compared to conventional pharmaceutical drugs.
Saw palmetto is frequently combined with other herbs that have shown benefit for prostate function to produce safe and effective preparations that have been clinically documented, which include stinging nettle, pyguem, pumpkin seed and tomato extract.
Stinging nettle root extract contains high amounts of lignan, which is responsible for the roots ability to bind to sex hormone-binding globulin (SHBG), key for its use in prostate problems. As men age, their SHBG level increases, making them more susceptible to abnormal cell proliferation. Stinging nettle has a strong affinity for SHBG, thereby limiting the amount of testosterone and oestrogen that can bind to it and influence cell proliferation.
It has been shown to reduce the risk of abnormal prostate cell proliferation, decreasing night-time urinary frequency while increasing urinary flow-rate and reducing residual urine. Stinging nettle also encourages hormonal balance and improves the quality of life of people with BPH.
Pygeum extract contains phytosterols which can inhibit prostaglandin synthesis, thereby reducing the abnormally high levels of prostaglandin normally found in BPH. The ferulic acid esters found in pygeum reduces prostatic cholesterol levels by limiting synthesis of testosterone. The extract has an anti-inflammatory effect and hence decreases inflammation in prostate tissue. Clinical effects of pygeum extract include reduction of prostate size, decreased night-time urinary frequency, reduction in residual urine and urinary urgency. Overall, it also works to improve the quality of life in men with BPH.
Pumpkin seed extract contains phytosterols, curcubitin and selenium. The extract inhibits 5-alpha-reductase, preventing the conversion of testosterone to dihydroxytestosterone. It has an inhibitory effect on aromatase, preventing androgens like testosterone from converting to oestrogen.
Clinical studies have shown that a remarkable reduction in urinary frequency during the day and night can be achieved with this extract. Urinary flow rate is also increased while residual urine is reduced.
(standardised to contain 5% lycopene)
Lycopene is a phytochemical that gives tomatoes their bright red colour. People who have diets rich in tomatoes, which contain lycopene, appear to have a lower risk of certain types of cancer, especially cancers of the prostate, lung, and stomach3.
All the above herbal ingredients for prostate health can be bought separately or together in a single supplement. As most recent studies carried out on saw palmetto for men with BPH used standardised saw palmetto extract, it is best to look for a preparation containing at least 160mg standardised saw palmetto extract containing a minimum of 85-95% fatty acids.
1. Bent S, Kane C, Shinohara K, Neuhaus J, Hudes ES, Goldberg H, et al. Saw Palmetto for Benign Prostatic Hyperplasia. New England J Med. Feb 9, 2006; 354 (6) : 557-566
2. WiltTJ, Ishani A, Stark G, MacDonald R, Lau J, Mulrow C. Saw Palmetto extracts for benign prostatic hyperplasia. The Cochrane Database of Systematic Reviews 2002, Issue 3. Art. No.: CD001423. DOI: 10.1002/ 14651858.CD001423
3. American Cancer Society