Ingredients commonly found in chocolate, berries, tea and wine may offer some protection against type 2 diabetes, a new study indicates.

It looked at the role of flavonoids - compounds found in plants that generally have powerful antioxidant and anti-inflammatory properties.

Researchers at the University of East Anglia in the UK monitored the progress of almost 2,000 people, in one of the first large scale studies among humans to assess how these compounds may reduce the risk of diabetes.

"Laboratory studies have shown these types of foods might modulate blood glucose regulation - affecting the risk of type 2 diabetes. But until now little has been know about how habitual intakes might affect insulin resistance, blood glucose regulation and inflammation in humans," explained lead researcher, Dr Aedin Cassidy.

The participants completed food questionnaires to assess how much flavonoids they were consuming. Blood samples were taken and insulin resistance was also assessed.

The study found that people who consumed high levels of flavonoids, including anthocyanins, which are found in, for example, chocolate and berries, appeared to be protected against type 2 diabetes.

"We found that those who consumed plenty of anthocyanins and flavones had lower insulin resistance. High insulin resistance is associated with type 2 diabetes, so what we are seeing is that people who eat foods rich in these two compounds - such as berries, herbs, red grapes and wine - are less likely to develop the disease.

"We also found that those who ate the most anthocyanins were least likely to suffer chronic inflammation, which is associated with many of today's most pressing health concerns including diabetes, obesity, cardiovascular disease and cancer," Dr Cassidy explained.

The researchers also found that those who consumed the highest levels of these compounds had improved levels of the protein adiponectin. This helps regulate certain metabolic processes, including glucose levels.

"What we don't yet know is exactly how much of these compounds are necessary to potentially reduce the risk of type 2 diabetes," Dr Cassidy noted.

Details of these findings are published in the Journal of Nutrition.