Blueberries, and berries in general, are among foods labeled as “diabetes superfoods” by the American Association of Diabetes.
Food science researchers at the University of Illinois have found that fermenting berries may improve their antidiabetic potential even more.
Recent research at the U of I includes the development of an alcohol-free blueberry-blackberry “wine” that those suffering from diabetes — who typically must avoid alcohol — can enjoy, while potentially reducing the effects of Type 2 diabetes.
“There are 100 million people around the world who have diabetes and that is increasing, without counting the ones who may be pre-diabetic and not know it.”
Previous research has shown that dietary blueberries may play a role in reducing hyperglycemia in obese mice.
Therefore researchers wanted to determine if a fermented, dealcoholized blueberry-blackberry beverage would enhance the potential of the phenolic compounds in the berries that are responsible for reducing diabetic markers.
A new study shows that the fermented berry beverage did reduce the development of obesity and blood glucose levels in mice on a high-fat diet.
The researchers had already determined that the berries, when fermented at low temperatures, resulted in an improved and higher concentration of anthocyanins.
Anthocyanins, found in the pigments of fruits such as blueberries, grapes, and apples, have been shown to promote insulin sensitivity, decrease blood glucose levels in the blood, and enhance insulin secretion.
A previous cell culture study with the alcohol-free blueberry-blackberry wine, showed good results toward inhibiting enzymes related to glucose absorption.
The beverage included a ratio of 70 percent fermented blackberries to 30 percent fermented blueberries.
The berries were collected from varieties grown at U of I’s Dixon Springs Agricultural Research Station in southern Illinois.
Alcohol was removed from the beverage by rotoevaporation and was replaced with water. Some of the sugars left over after fermentation were also removed in the process.
During the study, groups of mice with diet-induced obesity and hyperglycemia were given the fermented berry beverage or the beverage with higher or lower enriched concentrations of the anthocyanins.
While benefits were seen in all groups drinking the fermented beverage, de Mejia says the group on the highest concentration of anthocyanins (2x) showed the greatest results.
This included no increase in body weight, which de Mejia says was a surprise.
The researchers also observed that glucose was deposited into tissue more than absorbed by and present in the blood, as well.
They also saw an effect on oxidative stress in the obese mice.
Regarding the mechanism of action in reducing the diabetic effects, de Mejia says that the antioxidant power of the anthocyanins plays a very important role.
Producing this berry wine, complete with the benefits of fermentation but without the alcohol, provides an opportunity for wine makers, de Mejia says.