Researchers from BGG Japan, Beijing Gingko-Group Biological Technology and Miura Clinic jointly collaborated to evaluate the safety of saw palmetto oil consumed at five times above the recommended daily intake.
The findings were published in the journal of Japanese Pharmacology &Therapeutics.
Saw palmetto fruit is used in Chinese medicine to treat urological diseases, and its phytosterol is known to be an effective anti-inflammatory agent for prostate tissues.
It is often used as a supplement, with many studies reporting on its benefits, but researchers believed this is the first study evaluating excessive consumption at five times the daily limit.
The study involved 20 healthy adults aged 26 to 64 years, who were asked to consume five capsules of saw palmetto fruit extract (400mg each) daily for four weeks.
This was equivalent to 6.25 times the normal dose. According to the researchers, commercially available saw palmetto supplements generally contain approximately 320mg of saw palmetto extract.
Measurements on weight, BMI, blood pressure, pulse, blood, and urine were taken at four intervals (before the study, 2 and 4 weeks into study, and 2 weeks after completion).
There was no significant changes seen in the weight, BMI, blood pressure categories.
The findings also reported that no participants experienced side effects or allergic symptoms throughout the study period.
Researchers said: “Previous studies have reported side effects including nausea, vomiting, constipation, diarrhoea, abdominal discomfort, and gastrointestinal symptoms such as stomach pain, dizziness, fatigue, headache, muscle pain or hypertensive symptoms, although these were not observed in this study.
“We thus conclude from these results that there are no safety concerns with consuming 6.25 times the amount of saw palmetto oil normally recommended (320mg per day) in healthy adults,” they added.
The study was funded by BGG Japan.
In a separate study published last year in the journal of Pharmacometrics, researchers from Yawata Corportation, BGG Japan, Beijing Gingko-Group Biological Technology and Medical Corporation Seishinkai jointly collaborated to study the improvement of urination issues in men with consumption of saw palmetto fruit extract.
A total of 44 Japanese men aged 40 to 69 years with urination issues were given either a saw palmetto fruit extract or a placebo capsule to consume once daily for 12 weeks.
The study reported the treatment group experienced a significant improvement in urination issues after 12 weeks (p=0.007).
The safety evaluation also revealed that the consumption of saw palmetto fruit extract was safe under the conditions of the study, and no medical issues were observed.
Source: Japanese Pharmacology &Therapeutics
“A clinical study for evaluating the safety of excessive consumption of saw palmetto extract”
Authors: Takahiro Sekikawa, et al.
“A Verification Study on the Improvement of Urination Issues with Ingestion of Saw Palmetto Fruit Extract: A Randomized, Double-Blind, Parallel-Group, Placebo-Controlled Study”
Authors: Misaki Kushima, et al.