What happened? A new study reports that saw palmetto — a nutritional supplement widely used to treat prostate enlargement — is ineffective in relieving symptoms of enlarged prostate (benign prostatic hyperplasia, or BPH).

Saw palmetto is thought to prevent the breakdown of testosterone into a form of the hormone that increases prostate growth. In fact, earlier studies have shown saw palmetto to be as effective as the prescription medication finasteride. But the latest study disputes those findings.

Among 225 study participants, saw palmetto was no more effective than a placebo in improving urinary symptoms or objective measurements of prostate enlargement — regardless of the severity of symptoms or size of the prostate gland.

What does this mean to you? The study didn't identify any adverse effects from taking saw palmetto. So there's no harm in continuing to use it, if you think it's working for you. But if you're considering other treatments for enlarged prostate, discuss your options with your doctor. There are many proven ways to treat the signs and symptoms of an enlarged prostate — including medication, heat therapy, stents and various surgical procedures.