31 May 2024 – A diet high in flavonoid-rich foods and beverages may reduce the risk of developing type 2 diabetes by up to 28%, according to a new study published in Nutrition & Diabetes.
Study Overview:
Researchers investigated the relationship between flavonoid intake and the onset of type 2 diabetes in a large cohort from the UK Biobank, which includes over 500,000 adults recruited between 2006 and 2010. The study assessed flavonoid intake of 113,097 participants through multiple 24-hour dietary surveys, analyzed using the United States Department of Agriculture databases.
Key Findings:
Participants with higher consumption of flavonoid-rich foods were typically female, older, physically active, and had higher educational levels. The average daily flavonoid intake was 805.7 milligrams, with polymers and flavan-3-ols contributing 67% and 22% of the total intake, respectively. Tea was the primary source of these compounds, while flavones, mainly from peppers, contributed the least.
The study found that a higher Flavodiet Score (FDS)—equivalent to consuming six servings of flavonoid-rich foods per day—was associated with a 28% lower risk of developing type 2 diabetes compared to a lower FDS of one serving per day. Each additional daily serving of flavonoid-rich foods reduced diabetes risk by 6%. Specifically, four servings of black or green tea per day were linked to a 21% lower risk, one serving of berries per day to a 15% lower risk, and one serving of apples per day to a 12% lower risk.
Mechanisms and Implications:
The analysis suggested that flavonoid-rich diets positively affect weight management, glucose metabolism, inflammation, and kidney and liver functions, contributing to a reduced risk of type 2 diabetes. Flavonoids, particularly anthocyanins, flavan-3-ols, and flavonols, were found to enhance insulin secretion and signaling, improve glucose transport, and metabolism.
Despite the positive findings, the study population’s homogeneity—middle-aged British adults—may limit the generalizability to non-European populations.
Expert Opinions:
Megan Hilbert, RDN, highlighted that the study supports the understanding of flavonoids’ role in reducing inflammation and aiding weight management, which can lower the risk of type 2 diabetes. Kelsey Costa, MS, RDN, emphasized that the study’s large cohort and substantial follow-up reinforce the evidence of flavonoids’ protective role against diabetes. Costa also noted the importance of controlling for alcohol intake, which the study did by reassessing data excluding red wine, confirming that the protective association remained significant.
Practical Recommendations:
Experts advise increasing the intake of flavonoid-rich foods, such as grapes, oranges, grapefruit, sweet peppers, onions, dark chocolate, black and green tea, apples, and berries. These dietary changes can enhance overall health and reduce the risk of chronic conditions, including type 2 diabetes.
Conclusion:
Incorporating a variety of flavonoid-rich foods into a balanced diet offers substantial health benefits. While further research is needed to identify the most anti-diabetic foods and optimal consumption levels, prioritizing these foods can help individuals take proactive steps to improve their well-being.