You may have seen raspberry-based supplements popping up on store shelves. The interest stems in part from studies that suggest a key ingredient, raspberry ketone, could help burn fat.
Raspberries are popular from picnics to the dinner tables. But recently, an active ingredient in the berry has caught on with dieters, bolstered by supporters like television Dr. Mehmet Oz.
Raspberry ketone is the compound that produces the aroma in the raspberry. One overseas study found that the ketone helped prevent weight gain in mice.
A more recent study in human cells suggested that the ketone increased their ability to break down fat.
Sharon Meyer is a nutritionist with the Health and Healing Institute at California Pacific Medical Center in San Francisco, "Raspberry ketone have their place, but it's the extraction that I think is complicated."
She's concerned about the expanding market for ketone supplements and extracts. While she believes the studies are intriguing, she says there's no evidence that the weight loss effect of a specific ingredient translates into the complex human metabolism.
"And I've had some patients who came in and I said, 'why don't you try it and see?' And they've come back six to eight weeks later and said it's not working," Meyer said.
Doctor Melina Jampolis is a Bay Area physician specializing in nutrition. She points to encouraging lab studies from the past that have fallen short in clinical application.
"10 years ago when hormone Lepton was first discovered and they found when they injected it into fat mice, they quickly got thin," Jampolis said. "We thought we has the cure for obesity. Unfortunately, the human trials did not translate."
Both believe the raspberry ketone are worth further study, especially given their effect on inflamation in human cells. But with current data, neither would recommend the ketone alone for weight loss.
"Anytime there's anything around weight loss everyone jumps on the bandwagon looking for an easy fix, and there's no such thing," Meyer said.
Still, researchers are interested in several compounds contained in raspberries for potential effects on cancer and other diseases. Studies on those potential benefits are ongoing.
written and produced by Tim Didion