Anthocyanins may help fight diabetes

Anthocyanins, a class of plant pigments responsible for the colour of many fruits such as cherries and blackberries, increased insulin production in animal pancreatic cells by 50 per cent, according to the study.

"It is possible that consumption of cherries and other fruits containing these compounds [anthocyanins] could have a significant impact on insulin levels in humans,"​ said study leader Muralee Nair, a natural products chemist at Michigan State University.

"We're excited with the laboratory results so far, but more studies are needed,​ he added.

The potent antioxidant compounds have previously been associated with a variety of health benefits, including protection against heart disease and cancer.

But the new study shows that they also have promise for both the prevention of type 2 diabetes, on the rise around the world, and for helping control glucose levels in those who already have the condition.

Diabetes has already increased by one-third during the 1990s, due to the prevalence of obesity and an ageing population. The worldwide numbers are expected to climb from 194 million people to more than 333 million diabetics by 2025, according to the International Diabetes Federation.

Food and supplement makers are increasingly looking at ways to help slow the onset of the disease and such products may be the most efficient way to provide the beneficial anthocyanins, according to Nair.

The researcher's team tested several types of anthocyanins extracted from tart cherries, popular in the United States, and the Cornelian cherry, which is widely consumed in Europe. They investigated their effects on mouse pancreatic-beta cells, which normally produce insulin in the presence of high concentrations of glucose.

Compared to cells that were not exposed to anthocyanins, exposed cells were associated with a 50 per cent increase in insulin levels, the researchers say.

The mechanism of action by which these anthocyanins boost insulin production is not known, Nair said, but the team is currently feeding anthocyanins to a group of obese, diabetic mice to determine how the chemicals influence insulin levels in live subjects.

Scientists in Nair's laboratory have also developed a patented process for removing sugar from fruit extracts that contain anthocyanins. This could lead to sugar-free products for people with diabetes.

The study is scheduled to appear in the 5 January issue of the Journal of Agricultural and Food Chemistry​. The online version was initially published on 17 December on the journal's website​.