Over a 10-week trial, the high-fat-fed mice developed fatty liver and diabetic symptoms -- "the same metabolic consequences we see in many overweight, sedentary people," Shay said.
But the chubby mice that got the extracts accumulated less fat in their livers, and they had lower blood sugar, than those that consumed the high-fat diet alone. Ellagic acid proved to be a powerhouse in this experiment, too, lowering the high-fat-fed mice's blood sugar to nearly the levels of the lean, normally fed mice.
When Shay and his colleagues analyzed the tissues of the fat mice that ate the supplements, they noted higher activity levels of PPAR-alpha and PPAR-gamma, two proteins that work within cells to metabolize fat and sugar.
Shay hypothesizes that the ellagic acid and other chemicals bind to these PPAR-alpha and PPAR-gamma nuclear hormone receptors, causing them to switch on the genes that trigger the metabolism of dietary fat and glucose. Commonly prescribed drugs for lowering blood sugar and triglycerides act in this way, Shay said.
The goal of his work, he added, is not to replace needed medications but to guide people in choosing common, widely available foods that have particular health benefits, including boosting metabolic function.
"We are trying to validate the specific contributions of certain foods for health benefits," he said. "If you're out food shopping, and if you know a certain kind of fruit is good for a health condition you have, wouldn't you want to buy that fruit?"
The research was supported by the Institute of Food and Agricultural Science at the University of Florida and Florida Department of Agriculture and Consumer Services. The study appears in the January issue of the Journal of Nutritional Biochemistry.
Shay's research with mice was supported by the Blue Mountain Horticultural Society, the Erath Family Foundation, and the OSU College of Agricultural Sciences.