michael barry
Senior Member
- Reaction score
- 12
These guys took 106 mgs of saw palmetto three times a day, for a total of 318 mgs, which is about the normal hairloss dose of the stuff. They also took nettle, pumpkin seed extract, and some lemon extract.........................
HerbalGram. 2001;53:22-24 American Botanical Council
Reviewed: Marks LS, Hess DL, Dorey FJ, et al. Tissue effects of saw palmetto and finasteride: Use of biopsy cores for in situ quantification of prostatic androgens. Urology. 2001;57:999-1005.
Summary: Using prostate tissue samples obtained by needle biopsy, researchers compared tissue levels of testosterone (T) and dihydrotestosterone (DHT) in men with symptomatic benign prostatic hyperplasia (BPH) taking finasteride, placebo, or a saw palmetto herbal blend (SPHB). Tissue samples were obtained from three groups of men participating in different clinical trials: (1) 15 men receiving finasteride (Proscar®) treatment (5 mg/day) for 3 months or longer versus 7 untreated controls; (2) 22 men undergoing prostate adenomectomy (surgical excision of the gland) to rule out cancer (n = 18) or transurethral resection (a surgical technique used to allow relief of prostatic obstruction of urine flow in men with BPH) for the relief of obstruction (n = 4); (3) 44 men receiving either the SPHB (n = 21) or placebo (n = 23) for six months. Serum levels of T and DHT were also measured for each patient. The SPHB used in the original clinical trial1 is a combination supplying 106 mg of saw palmetto (Serenoa repens [W. Bartram] Small, Arecaceae) extract, stinging nettle (Urtica dioica L. ssp. dioica, Urticaceae) root extract (80 mg), pumpkin (Curcubita pepo L., Curcurbitaceae) seed extract (160 mg), flavonoids extracted from lemon (Citrus x limon [L.] Osbeck, Rutaceae) (33 mg), and vitamin A (190 mg) per capsule (supplied by Nutrilite, of Buena Park, California). One capsule of the product was taken three times per day.
A total of 244 prostate samples were analyzed - 40 from the prostate adenomectomy group, 44 from the finasteride study, and 160 from the SPHB trial. In men taking finasteride, prostate tissue levels of DHT were decreased significantly when compared to untreated men (p < 0.01). Conversely, prostate tissue levels of T were significantly increased - five to ten times - in those taking finasteride compared to untreated controls (p < 0.01). While serum (i.e., bloodstream) levels of T remained similar, serum levels of DHT were also significantly reduced in men taking finasteride compared to controls (p < 0.01).
Men taking SPHB had a significant decrease in prostate tissue levels of DHT from baseline to 6 months of treatment (p = 0.005). However, this reduction was not statistically significant when compared to the placebo group. The 6-month decline in DHT for the SPHB group was 32%. In comparison, the finasteride effect on prostate tissue levels of DHT was an 80% reduction compared to untreated men. Treatment with SPHB led to no changes in prostate tissue levels of T or in serum levels of T or DHT. Of particular interest, serum levels of prostate-specific antigen (PSA) decreased by approximately 50% in men taking finasteride compared to no change in men taking SPHB.
The authors of the study conclude that compared to finasteride, the SPHB-induced suppression of prostatic DHT levels is modest but significant enough to support the hypothesis that inhibition of the enzyme 5-alpha reductase (5-AR), which is responsible for the converstion of T to DHT, may be a mechanism for saw palmetto and the SPHB used in the study.
Comments/Opinions: Directed by Leonard Marks, M.D., head of the Urological Sciences Research Foundation, this is the first American study to explore potential mechanisms of action for saw palmetto. While a meta-analysis of clinical trials published in the Journal of the American Medical Association in 1998 concluded that saw palmetto preparations are safe and effective in treating many of the symptoms associated with BPH,2 there has been little consensus on the how saw palmetto achieves this clinical effect.
DHT is the major androgenic hormone in the prostate and is needed throughout life for the growth and maintenance of the gland. It is derived from T and this conversion is catalyzed by 5-AR. As excessive accumulation of DHT is thought to be a potential contributor to the development of BPH in middle age and older males, drugs that inhibit 5-AR (i.e. finasteride) have been developed to treat BPH. Some herbal experts and European researchers have suggested that this action may partially explain how saw palmetto works.
In vitro and animal studies have suggested an antiandrogenic action for the liposterolic extract of saw palmetto.3 In vitro studies have shown inhibition of the enzymes 5-AR and 3-ketosteroid reductase as well as inhibition of the binding of DHT to prostate cells.4,5 In addition, in vitro as well as in vivo research has found that saw palmetto extract inhibits the production of basic fibroblast growth factor and epidermal growth factor.6,7 In addition to DHT, these growth factors are also thought to contribute to BPH.
There have been conflicting results regarding the ability of saw palmetto extracts to inhibit 5-AR - particularly when compared to finasteride. One in vitro study found minimal 5-AR inhibition when compared directly to finasteride.8 However, one study showed that at the therapeutic dose of 320 mg/day, saw palmetto extract does inhibit 5-AR, 9 and other studies have shown inhibition of both type I and type II isoenzymes of 5-AR.10,11 One in vitro study found that inhibition of 5-AR was limited to only prostate cells and not cells from other parts of the body.12 Unlike other 5-AR inhibitors, saw palmetto has not shown inhibition of prostate-specific antigen (PSA) secretion, even after stimulation with testosterone in vitro.13 As noted below, PSA is a serum marker used to detect possible prostate cancer. Inhibition of PSA secretion may, in some cases, block early detection of prostate cancer. One in vivo study found that decreased levels of DHT were significant only in the periurethral area.7 This may suggest a more localized effect for the extract and may partly explain why in clinical trials administration of saw palmetto extracts have not resulted in significant reduction in prostate size. In fact, the current study found no reduction in prostate size for men taking SPHB while those taking finasteride had a 20% reduction.
While the study by Dr. Marks and colleagues suggests that inhibition of 5-AR (likely far more modest than that noted for finasteride) may partially explain the modest reduction in DHT levels noted for men taking the SPHB product, further studies are needed to confirm the earlier European studies noted above.
Finally, the results of this study may be viewed critically as the product used contains not only saw palmetto but also nettle root and pumpkin seed oil, two other products sometimes used for the symptomatic treatment of BPH and both approved by the German Commission E for this use (albeit with much less clinical evidence than saw palmetto).14 Interestingly, an earlier Italian study using a monopreparation of saw palmetto (Permixon®, Pierre Fabre, Paris) found a 50% reduction in prostate tissue levels of DHT in men with BPH taking 320 mg of the extract per day.7 The daily dosage of saw palmetto extract used in the current study equals that used in the Italian study. Could some ingredient in the combination product counter some of the effect of saw palmetto? This could only be answered with a comparison study of the two products.
Practice Implications: The results of this study confirm that a saw palmetto herbal combination product does reduce prostate tissue levels of DHT- an effect that may partially explain the clinical effectiveness of saw palmetto for the treatment of mild to moderate BPH. Further studies are needed to determine the degree to which saw palmetto inhibits 5-AR, the likely explanation for the effect noted in this study. Perhaps most notable to the healthcare professional is the lack of effect on PSA levels noted in the study. An important serum marker for prostate cancer, the findings of this study confirm the lack of effect for saw palmetto on PSA noted in earlier clinical trials.15-17
While the liposterolic extract of saw palmetto at a daily dosage of 320 mg appears to be a safe and effective alternative to finasteride, future clinical trials should compare the herbal extract to the class of BPH drugs known as alpha-blockers (e.g. Cardura®, Flomax®, and Hytrin®) which are far more commonly prescribed than finasteride.
-Donald J. Brown, N.D.
References
HerbalGram. 2001;53:22-24 American Botanical Council
Reviewed: Marks LS, Hess DL, Dorey FJ, et al. Tissue effects of saw palmetto and finasteride: Use of biopsy cores for in situ quantification of prostatic androgens. Urology. 2001;57:999-1005.
Summary: Using prostate tissue samples obtained by needle biopsy, researchers compared tissue levels of testosterone (T) and dihydrotestosterone (DHT) in men with symptomatic benign prostatic hyperplasia (BPH) taking finasteride, placebo, or a saw palmetto herbal blend (SPHB). Tissue samples were obtained from three groups of men participating in different clinical trials: (1) 15 men receiving finasteride (Proscar®) treatment (5 mg/day) for 3 months or longer versus 7 untreated controls; (2) 22 men undergoing prostate adenomectomy (surgical excision of the gland) to rule out cancer (n = 18) or transurethral resection (a surgical technique used to allow relief of prostatic obstruction of urine flow in men with BPH) for the relief of obstruction (n = 4); (3) 44 men receiving either the SPHB (n = 21) or placebo (n = 23) for six months. Serum levels of T and DHT were also measured for each patient. The SPHB used in the original clinical trial1 is a combination supplying 106 mg of saw palmetto (Serenoa repens [W. Bartram] Small, Arecaceae) extract, stinging nettle (Urtica dioica L. ssp. dioica, Urticaceae) root extract (80 mg), pumpkin (Curcubita pepo L., Curcurbitaceae) seed extract (160 mg), flavonoids extracted from lemon (Citrus x limon [L.] Osbeck, Rutaceae) (33 mg), and vitamin A (190 mg) per capsule (supplied by Nutrilite, of Buena Park, California). One capsule of the product was taken three times per day.
A total of 244 prostate samples were analyzed - 40 from the prostate adenomectomy group, 44 from the finasteride study, and 160 from the SPHB trial. In men taking finasteride, prostate tissue levels of DHT were decreased significantly when compared to untreated men (p < 0.01). Conversely, prostate tissue levels of T were significantly increased - five to ten times - in those taking finasteride compared to untreated controls (p < 0.01). While serum (i.e., bloodstream) levels of T remained similar, serum levels of DHT were also significantly reduced in men taking finasteride compared to controls (p < 0.01).
Men taking SPHB had a significant decrease in prostate tissue levels of DHT from baseline to 6 months of treatment (p = 0.005). However, this reduction was not statistically significant when compared to the placebo group. The 6-month decline in DHT for the SPHB group was 32%. In comparison, the finasteride effect on prostate tissue levels of DHT was an 80% reduction compared to untreated men. Treatment with SPHB led to no changes in prostate tissue levels of T or in serum levels of T or DHT. Of particular interest, serum levels of prostate-specific antigen (PSA) decreased by approximately 50% in men taking finasteride compared to no change in men taking SPHB.
The authors of the study conclude that compared to finasteride, the SPHB-induced suppression of prostatic DHT levels is modest but significant enough to support the hypothesis that inhibition of the enzyme 5-alpha reductase (5-AR), which is responsible for the converstion of T to DHT, may be a mechanism for saw palmetto and the SPHB used in the study.
Comments/Opinions: Directed by Leonard Marks, M.D., head of the Urological Sciences Research Foundation, this is the first American study to explore potential mechanisms of action for saw palmetto. While a meta-analysis of clinical trials published in the Journal of the American Medical Association in 1998 concluded that saw palmetto preparations are safe and effective in treating many of the symptoms associated with BPH,2 there has been little consensus on the how saw palmetto achieves this clinical effect.
DHT is the major androgenic hormone in the prostate and is needed throughout life for the growth and maintenance of the gland. It is derived from T and this conversion is catalyzed by 5-AR. As excessive accumulation of DHT is thought to be a potential contributor to the development of BPH in middle age and older males, drugs that inhibit 5-AR (i.e. finasteride) have been developed to treat BPH. Some herbal experts and European researchers have suggested that this action may partially explain how saw palmetto works.
In vitro and animal studies have suggested an antiandrogenic action for the liposterolic extract of saw palmetto.3 In vitro studies have shown inhibition of the enzymes 5-AR and 3-ketosteroid reductase as well as inhibition of the binding of DHT to prostate cells.4,5 In addition, in vitro as well as in vivo research has found that saw palmetto extract inhibits the production of basic fibroblast growth factor and epidermal growth factor.6,7 In addition to DHT, these growth factors are also thought to contribute to BPH.
There have been conflicting results regarding the ability of saw palmetto extracts to inhibit 5-AR - particularly when compared to finasteride. One in vitro study found minimal 5-AR inhibition when compared directly to finasteride.8 However, one study showed that at the therapeutic dose of 320 mg/day, saw palmetto extract does inhibit 5-AR, 9 and other studies have shown inhibition of both type I and type II isoenzymes of 5-AR.10,11 One in vitro study found that inhibition of 5-AR was limited to only prostate cells and not cells from other parts of the body.12 Unlike other 5-AR inhibitors, saw palmetto has not shown inhibition of prostate-specific antigen (PSA) secretion, even after stimulation with testosterone in vitro.13 As noted below, PSA is a serum marker used to detect possible prostate cancer. Inhibition of PSA secretion may, in some cases, block early detection of prostate cancer. One in vivo study found that decreased levels of DHT were significant only in the periurethral area.7 This may suggest a more localized effect for the extract and may partly explain why in clinical trials administration of saw palmetto extracts have not resulted in significant reduction in prostate size. In fact, the current study found no reduction in prostate size for men taking SPHB while those taking finasteride had a 20% reduction.
While the study by Dr. Marks and colleagues suggests that inhibition of 5-AR (likely far more modest than that noted for finasteride) may partially explain the modest reduction in DHT levels noted for men taking the SPHB product, further studies are needed to confirm the earlier European studies noted above.
Finally, the results of this study may be viewed critically as the product used contains not only saw palmetto but also nettle root and pumpkin seed oil, two other products sometimes used for the symptomatic treatment of BPH and both approved by the German Commission E for this use (albeit with much less clinical evidence than saw palmetto).14 Interestingly, an earlier Italian study using a monopreparation of saw palmetto (Permixon®, Pierre Fabre, Paris) found a 50% reduction in prostate tissue levels of DHT in men with BPH taking 320 mg of the extract per day.7 The daily dosage of saw palmetto extract used in the current study equals that used in the Italian study. Could some ingredient in the combination product counter some of the effect of saw palmetto? This could only be answered with a comparison study of the two products.
Practice Implications: The results of this study confirm that a saw palmetto herbal combination product does reduce prostate tissue levels of DHT- an effect that may partially explain the clinical effectiveness of saw palmetto for the treatment of mild to moderate BPH. Further studies are needed to determine the degree to which saw palmetto inhibits 5-AR, the likely explanation for the effect noted in this study. Perhaps most notable to the healthcare professional is the lack of effect on PSA levels noted in the study. An important serum marker for prostate cancer, the findings of this study confirm the lack of effect for saw palmetto on PSA noted in earlier clinical trials.15-17
While the liposterolic extract of saw palmetto at a daily dosage of 320 mg appears to be a safe and effective alternative to finasteride, future clinical trials should compare the herbal extract to the class of BPH drugs known as alpha-blockers (e.g. Cardura®, Flomax®, and Hytrin®) which are far more commonly prescribed than finasteride.
-Donald J. Brown, N.D.
References
