People struggling to keep their New Year’s promise to lose weight may feel tempted to click on the Internet ads that promise to tell one weird secret doctor’s don’t want you to know about açai berries’ fat-fighting power. But the pop-ups may be promoting the wrong berry.

Swedish scientists published experimental results that suggest lingonberries, black currants and bilberries could be wonder fruits for the waist line, while fruit-fed mice fattened on açai berries.

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The experiment didn’t start out as an açai berry mythbuster. The Lund University team included the berries because of their reputation as a weight-loss supplement.

“Instead, the opposite happened,” said Karin Berger, diabetes researcher at Lund University, in a press release. “In our study, the açai berries led to weight gain and higher levels of fat in the liver.”

The rodent in the experiment held a genetic predisposition to put on fat. Biologists used that mouse breed as a model for overweight humans. Most mice received a high fat diet along with either lingonberry, bilberry, raspberry, crowberry, blackberry, prune, blackcurrant, açai berry or no berries. Another group of mice kept their New Years resolutions and were fed a low-fat diet.

Berry Bling Shines on Forever

After 13 weeks of the various diets, the biologists measured the mice’s weight and other health indicators. Lingonberries emerged as the health food champ, while several other berries also proved beneficial.

“This study demonstrated that daily supplementation with lingonberries and also blackcurrants and bilberries had pronounced antiobesity and beneficial metabolic effects in high-fat fed mice,” wrote the study authors in the Journal of Nutrition and Metabolism.

Can Fruit Kick Candy to the Curb?

Lingonberry-fed mice gained only slightly more weight than the low-fat diet mice, and both groups maintained similar blood sugar and insulin levels, important factors for diabetes patients. Lingonberry, blackcurrant, raspberry or bilberry munching mice all gained less weight than mice that ate high-fat, berries-free diets. Mice in the lingonberry group also had lower cholesterol and less fatty livers than the high-fat, no berry mice.

However, people would have a hard time eating enough fresh lingonberries to match the quantity eaten by the mice.

“Up to 20 percent of our mice’s diet was lingonberries. It isn’t realistic for humans to eat such a high proportion. However, the goal is not to produce such dramatic effects as in the ‘high-fat’ mice, but rather to prevent obesity and diabetes by supplementing a more normal diet with berries,” said Berger.

Certain chemicals, called polyphenols, in the berries may relate to their health benefits, suggested the Swedish researchers. In particular, the mice fed on lingonberries and blackcurrants had high levels of particular polyphenols known as quercetin glucosides.

Photo: Lingonberry at Blefjell in Norway (Arnstein Rønning, Wikimedia Commons)