The extract is taken from the purple-black berries of a dwarf palm tree native to the West Indies and North America. Native Americans have used it therapeutically for centuries.
Today, saw palmetto is used as a supplement to relieve symptoms of benign enlargement of the prostate, a small gland found in men in the pelvis beneath the bladder. Symptoms include weak urine flow and urinary frequency, including at night.
Dr Sarah Brewer says: 'Saw palmetto is a commonly-used supplement to help men with prostate and lower urinary tract symptoms – particularly disruptive night-time visits to the toilet (nocturia) which disturb sleep for the sufferer and their bed partner.'
What does saw palmetto do?
Researchers are unsure exactly how saw palmetto works. One theory is that it may inhibit the action of an enzyme called 5-alpha reductase, which is found in the prostate. This enzyme converts the male hormone, testosterone, to another powerful hormone called dihydrotestosterone (DHT) which stimulates prostate growth. Another theory is that saw palmetto may have an anti-inflammatory effect.
The prostate gland commonly gets bigger with age and saw palmetto can help reduce the accompanying urinary symptoms.
Its active ingredients include fatty acids, flavonoids and plant sterols.
Around 3.2 million men in the UK, mostly aged over 50, experience symptoms associated with an enlarged prostate, most commonly in the form of benign prostatic hyperplasia (BPH), where the prostate gland gets bigger and presses on the bladder.
Symptoms of BPH include: a frequent need to pass urine (especially during the night); difficulty passing urine; weak urine flow (stopping and starting); a sudden, urgent need to go; incomplete bladder emptying; and, less commonly, blood in the urine.
Some studies have shown benefits when using saw palmetto for treating BPH, others have not. One review of 44 studies concluded that saw palmetto decreased nocturia by an average of almost one less trip to the toilet per night.
They also found men taking saw palmetto experienced a 72 per cent average improvement in BPH symptoms.
It has been argued, however, that some of these trials were too short to show any meaningful effects, and more research is needed.
Saw Palmetto ProstAid®is a supplement registered under the Traditional Herbal Registration scheme. THR registration means ingredients are of standardised quality and the remedy has been in traditional use for at least 30 years. Based on traditional use only, saw palmetto is said to help weak or interrupted urinary frequency and the need to urinate frequently, particularly at night.
Prostatitis is inflammation of the prostate gland. In one study, all men with chronic bacterial prostatitis received an antibiotic for 15 days and one group of 28 also took saw palmetto for eight weeks. All the men were found to be infection-free but the saw palmetto group reported significantly reduced pain and an improvement in urinary symptoms.
Getting saw palmetto from your diet
Saw palmetto is not available in food apart from teas. It is readily available in supplement form, though.
Saw palmetto is a natural supplement with few side effects when compared to conventional drugs for BPH. Mild side effects can include abdominal pain, nausea, tiredness, headache, decreased libido and rhinitis (runny nose).
It is recommended pregnant and breastfeeding women avoid it. There has also been some concern as to whether it could increase the anticoagulant effect of the drug warfarin.
Always seek your doctor's advice before taking saw palmetto, as some of the symptoms of BPH are similar to those of prostate cancer and you may need a check-up to eliminate this.
There are no established dose recommendations for saw palmetto supplements, but dosages of between 100-400mg twice daily are used to treat BPH. Experts suggest a dose of 160mg twice daily.
Take one capsule of Saw Palmetto ProstAid® (THR) twice daily (morning and evening). Each capsule contains 160mg saw palmetto extract.