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Table A

Individual Components of Saw Palmetto Fruit

Table B

Saw Palmetto: Summary of Adverse Effects in Clinical Trials

Table C

Saw Palmetto: Summary of a Clinical Case Reports (no relevant data available)

Table D

Saw Palmetto: Summary of Adverse Event Reports (no relevant data available)

Table E

Saw Palmetto: Summary of Animal Studies

Table F

Saw Palmetto: Summary of In Vitro Studies

Table G

Saw Palmetto: Related Substances that Might Suggest Risk


A. Summary

Saw palmetto is being widely used by men for prostate-related conditions, most notably benign prostate hyperplasia. Descriptions of saw palmetto are appearing in pharmacology texts for use in cystitis and for its antiedematous and antiandrogenic properties (Gennaro, 2000). There is a concern that these antiandrogenic properties pose a risk to males in utero because of the potential for deleterious effects on male genitalia.

Several pieces of evidence integrated together demonstrate that while there have not been documented cases of saw palmetto-induced birth defects in male offspring of humans or animals, there is a risk associated with saw palmetto ingestion by women.

It is well understood that testosterone, an androgen, or male sex hormone, is required for developing and maintaining masculine sexual characteristics. Testosterone is converted to the most active androgen DHT by 5-α-reductase, which then exerts the androgen action via androgen receptors.

In vitro data consistently demonstrate that saw palmetto extracts inhibit the testosterone conversion to DHT, including by inhibiting the 5-α-reductase enzyme. They also inhibit binding of DHT to androgenic receptors. Both of these actions would inhibit the androgen pathway if they occurred in vivo.

Animal data indicate that orally consumed saw palmetto preparations are antiandrogenic in vivo. Several animal studies were completed with oral administration of saw palmetto extracts following androgen stimulation of prostate hyperplasia. Studies indicate that saw palmetto extract at 50 to


Tables appear at the end of this appendix.

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