A plant-based diet is widely recognized for its ability to reduce the risk of type 2 diabetes. Expanding on this, researchers have now identified specific food items rich in flavonoids that could lower the risk of type 2 diabetes.

Flavonoids are natural components found in plant-based foods such as fruits, vegetables, grains, legumes, nuts, and certain beverages such as tea and wine. They are superfoods with antioxidative, anti-inflammatory, anti-mutagenic, and anti-carcinogenic properties. They have protective effects against various diseases such as cancer, Alzheimer's disease, and atherosclerosis.

According to a study published in the journal Nutrition and Diabetes, increasing the daily intake of flavonoid-rich foods by one serving could reduce the risk of type 2 diabetes by 6%. The researchers identified flavonoid-rich food items with the greatest benefits as black or green tea, berries, and apples.

The findings were based on a dietary assessment conducted among 113,097 participants from the U.K. Biobank. The flavonoid intake of the participants was estimated using two or more dietary assessments with the U.S. Department of Agriculture (USDA) databases.

The researchers determined the participants' average daily "Flavodiet Scores" by aggregating the intake of ten flavonoid-rich foods. The results showed that female participants, older individuals, physically active participants, and those with higher educational levels have typically higher Flavodiet scores.

Individuals who consumed an average of six servings of flavonoid-rich foods daily, as reflected by their higher Flaviodiet scores, had a 28% lower risk of developing type 2 diabetes, compared to those with lower scores, who consumed only one serving per day.

"In food-based analyses, higher intakes of black or green tea, berries, and apples were significantly associated with 21%, 15%, and 12% lower Type 2 diabetes risk. Among individual flavonoid subclasses, 19–28% lower risks of Type 2 diabetes were observed among those with the highest, compared to lowest intakes," the researchers wrote.

The researchers believe that the protective effect of flavonoid-rich foods could be "mediated by the beneficial effects of flavonoids on obesity/sugar metabolism, inflammation, and kidney and liver function."

However, there are certain limitations to the study. Since the study population includes middle-aged British adults, the results may not be completely generalizable to other populations. Also, there are chances that in some cases, flavonoid intake values may be misclassified.