TWO men seeking to boost sexual performance and grow bigger muscles instead ended up with advanced prostate cancer after taking "herbal" supplements, US doctors said.
They said many supplements marketed as "safe" and "natural" could contain unknown and potentially dangerous ingredients, and noted that the US Food and Drug Administration has little authority to regulate them.
"Physicians need to ask their patients not only about the prescription drugs they may be taking, but — perhaps even more importantly — about the over-the-counter drugs and supplements, which may have a profound impact on certain health conditions," Claus Roehrborn, chairman of urology at the University of Texas Southwestern medical school, said yesterday.
Dr Roehrborn's team became concerned about what it calls herbal/hormonal dietary supplements, or HHDSs, after two men developed aggressive prostate cancer within months of taking the same supplement.
The team analysed the product, which it did not name for legal reasons, and found it contained two hormones — testosterone and estradiol. When the product was tested on tumour cells in the lab, it fuelled the growth of prostate cancer cells more potently than testosterone alone, the team reported in the journal Clinical Cancer Research."We filed an adverse event report with the FDA, who issued a warning letter. The manufacturer responded by removing this HHDS product from the market," the researchers wrote.
"Individuals use HHDS for self-improvement, failure or distrust of conventional medicine, and because they believe that these natural products are safe and drug-free."
The researchers searched websites promoting such products and found they promised maintenance of a "youthful" heart, relief of stress, and improvements in stamina, energy, strength and virility.
The patients, a 67-year-old and a 51-year-old, have both survived but cancer has spread throughout their bodies.
"Unlike prescription and over-the-counter drugs, the law does not require nutritional supplements to undergo pre-market approval for safety and efficacy," the researchers wrote, with manufacturers allowed to assume the sole responsibility.
"Thus, the current Food and Drug Administration regulatory system provides little oversight or assurance that HHDS will have predictable pharmacological effects or even that product labels provide accurate information to consumers."
