The ripe berry of saw palmetto (Serenoa repens) is one of the most popular herbs in the US. It is used by men to manage the urinary tract symptoms linked to an enlarged prostate (known as benign prostatic hyperplasia or BPH).
However, results from recent trials using the fatty extract of saw palmetto in patients with BPH have been mixed. A much publicised trial in the New England Journal of Medicine in 2006 that found no difference against placebo may have been flawed because it used a US product that could have been adulterated with vegetable oil. The product was only tested for total fatty acids, not the free fatty acids that are characteristic of the fatty extract.
A large trial recently published in the Journal of the American Medical Association (JAMA) using a high quality European product also found no difference against placebo. The double- blind, multi-centre, placebo-controlled, randomised trial enrolled 369 men aged 45 years or older with BPH. Dosages used through the 72-week trial were one, two and then three doses of the fatty extract of saw palmetto (320mg/dose), with dose increases at 24 and 48 weeks. These increasing doses of saw palmetto extract did not reduce lower urinary tract symptoms (LUTS) more than placebo.
The JAMA trial is not without its detractors. One observer pointed out that the patients in the trial did not have very enlarged prostates. This was indicated by their low average PSA (prostate specific antigen) values and good urinary flow rates to start with. So perhaps it was difficult to see a change when there was not much of a problem in the first place!
Proven herbal relief for an uncomfortably swollen prostate
In contrast to these neutral studies on saw palmetto, the clinical data for stinging nettle root (Urtica dioica) in BPH remains consistently positive. There are four key placebo-controlled trials that have demonstrated its value in this condition.
But what is really interesting is the fact that saw palmetto combined with nettle root seems to be particularly effective for BPH symptoms. As before, there are four key clinical trials for the combination, this time two against placebo and two against standard drug treatments.
In a placebo-controlled clinical trial, 40 patients with BPH were treated with a nettle and saw palmetto extract combination (240mg/day of extract of nettle root, 320mg/day of fatty saw palmetto extract) or placebo over 24 weeks. Significant improvement was observed in the herbal treatment group, with peak flow up by 23% compared to 4% in the placebo group and prostate symptoms down by 40% compared to 7% for the placebo group.
Two herb combo performed as well as finasteride
In another randomised, double-blind, multi-centre clinical trial, the efficacy of the above combination of nettle and saw palmetto extracts was compared with the drug finasteride in the treatment of BPH stages I to II. A total of 516 patients completed a 48-week treatment with the herbal combination or finasteride (5mg/day). Both treatments significantly improved urinary flow and prostate symptoms and there was no significant difference between the two. Fewer adverse events were reported for the herbal combination.
The efficacy and tolerability of the same combination of saw palmetto and nettle root was investigated in 257 elderly, male patients suffering from LUTS caused by BPH in a prospective multi-centre trial. Patients treated with saw palmetto/nettle root exhibited a higher reduction in prostate symptoms after 24 weeks of double-blind treatment than patients in the placebo group. This applied to obstructive as well as irritative symptoms, and in patients with ‘moderate’ or ‘severe’ symptoms at baseline. The same combination of saw palmetto and nettle root reduced the subjective symptoms of BPH to an extent comparable to the drug tamsulosin. The two treatments were administered in a prospective, randomised, double-blind trial to patients suffering from BPH and not requiring surgery.
Given the recent trials on saw palmetto on its own for BPH have yielded neutral results, the case is even stronger for the value of a nettle root and saw palmetto combination, provided the doses in the above clinical trials are used
Is insulin resistance to blame for prostate problems?
While this positive evidence for the combination of nettle root and saw palmetto in BPH/LUTS is good news, the days of just taking prostate herbs as the only approach for BPH are now well and truly gone. BPH/LUTS is emerging as a lifestyle disease underpinned by chronic inflammation and insulin resistance (a lower sensitivity of the body to the hormone insulin) in many cases.
One theory gaining increasing credibility proposes that the higher circulating insulin associated with insulin resistance stimulates prostate growth. Multiple experimental, clinical and epidemiological studies have demonstrated the link between either hyperinsulinaemia (high serum insulin), elevated fasting blood glucose or type 2 diabetes and prostate enlargement and LUTS. An association with obesity has also been observed. The sympathetic over-activity (dominance) linked to obesity, metabolic syndrome and hypertension may increase the risk of developing LUTS. LUTS and metabolic syndrome have been shown to occur together.
Given this new understanding of BPH, emphasis needs to be also placed on appropriate weight-loss, treatment, dietary and exercise regimes for the management of insulin resistance and generalised inflammation. Of course, the saw palmetto/ nettle root combination will still be of value in helping to manage symptoms.To your better health,
Nutrition & Healing
Volume 6, Issue 5 – May 2012
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