Two medical studies now suggest fish oil supplements may not be a good idea for everybody.

The omega-3 fatty acids can protect us against heart disease and even Alzheimer's, but they can present a higher risk of prostate cancer to some patients, 43 percent higher.  That showed up in one study, so they checked it again, says Dr. Steven Canfield, a urologist at U.T. Health Medical School in Houston..

“It bore out,” Dr. Canfield says.  “So, there does seem to be an at-risk relationship there, with these omega-3 fatty acids and high-risk prostate cancer.”

He says doctors now have to find a balance between the benefits and the risks of those supplements.  So, what do you say to a patient?

“In patients who are taking them and are getting a benefit for other reasons, it's hard to tell them to stop doing that,” he says.  “But, when there are controversies then we certainly don't feel confidence telling somebody just to start.”