Patients who consume the widest variety of dietary flavonoids were found to have up to a 20% lower risk of type 2 diabetes and a 14% lower risk of all-cause mortality.
In a cohort study analysis of 124,805 adults in the UK Biobank, researchers examined the independent and combined associations of dietary flavonoid quantity and diversity with all-cause mortality and major chronic diseases.
The study, led by Benjamin H. Parmenter, PhD, of the School of Medical and Health Sciences, Edith Cowan University Belfast, UK.
Dietary flavonoid consumption was measured using repeated 24-hour Oxford WebQ dietary recalls.
Primary sources of flavonoid consumption were apples, beans and lentils, beer and cider, bell peppers, berries, butternut squash, cabbage and kale, celery, dark chocolate, fruit yogurt, grapefruits and grapefruit juice, herbal tea, mixed vegetables, olives, onion, orange and satsuma, orange juice, other vegetables, pears, pure fruit/vegetable juice, red wine, smoothies, tea, and white wine.
Participants were followed for a median of 8.7 to 10.6 years, with up to 11.8 years of follow-up. During this period, 5,780 deaths, 6,920 cardiovascular disease (CVD) cases, 3,421 type 2 diabetes cases, 9,441 cancers, 12,945 respiratory disease cases, and 1,921 neurodegenerative disease cases were recorded.
Both higher flavonoid quantity and greater diversity were independently associated with reduced risks of mortality and several chronic diseases. After adjusting for total flavonoid quantity, greater diversity remained protective.
Patients in the highest diversity quintile—consuming approximately 6.7 more effective flavonoid types per day—had a 14% lower risk of all-cause mortality, 10% lower risk of CVD, 20% lower risk of type 2 diabetes, 8% lower risk of cancer, and 8% lower risk of respiratory disease compared with those in the lowest quintile. There was no statistically significant association for neurodegenerative disease.
Further subclass analysis showed that greater diversity in flavan-3-ol and flavanone intake was linked to improved outcomes. For example, patients with the highest flavan-3-ol diversity had a 13% lower risk of type 2 diabetes and an 8% lower risk of cancer, while higher flavone diversity was linked to an 18% lower risk of neurodegenerative disease.
In a related narrative review published in Maedica: A Journal of Clinical Medicine, researchers examined the therapeutic potential of natural compounds, including flavonoids, in cancer treatment.
They reported that flavonoids such as quercetin and resveratrol may inhibit tumor growth in preclinical models of head and neck cancer by inducing cell cycle arrest and activating apoptotic pathways. The review also discussed other plant-derived compounds, such as curcumin and vincristine, that have demonstrated anticancer effects in laboratory and early clinical studies.
Taken together, the findings from both studies suggest that incorporating a wide range of flavonoid-rich foods may contribute to long-term health benefits and reduced chronic disease risk.
Expert Commentary: Scott D. Isaacs, MD, FACP, FACE, President American Association of Clinical Endocrinology
“Traditional dietary counseling emphasizes the importance of consuming enough fruits and vegetables, often focusing on total servings. This study suggests that the diversity of flavonoid-rich foods, such as berries, citrus, tea, and dark chocolate, is as important as the overall amount. In preventive care, this provides an opportunity for clinicians to encourage patients not only to increase their intake of plant-based foods but also to vary their choices. For example, instead of recommending increasing consumption of vegetables and fruits, specifically suggesting exploring different types of fruits and vegetables throughout the week. Adding in more variety can help patients consume a broader spectrum of flavonoids, increasing protective effects against chronic diseases.”
“The multiple organ system benefits seen in this study remind us of the interconnected nature of nutrition and overall health. When discussing risk reduction, physicians can use this evidence to highlight that dietary choices impact not just one aspect of health, but the entire body, including heart health, metabolic function, cognition, and overall well-being. This could mean including a discussion about diversity of plant-based foods into the broader conversations about diet and lifestyle. For example, in a discussion about risk reduction, it is helpful to explain that a varied, plant-rich diet can support weight management, glucose control, heart health, and even brain function. This holistic view can be motivating for patients because it views dietary changes to improve overall well-being, instead of addressing a single disease.”
“Translating complex research into simple, actionable guidance can be challenging, so it is helpful to find simple explanations. Most patients are not familiar with the term flavonoids, nor are they aware that there are different types of flavonoids. A strategy can be to focus on different types of healthy foods. I encourage patients to “eat a rainbow” by choosing a wide variety of colorful fruits and vegetables, as well as including foods like tea and dark chocolate in moderation. Sample meal plans and shopping lists can make these recommendations easier to follow. Another challenge can be barriers such as access (i.e., food deserts), cost, and cultural preferences.”
Full disclosures can be found in the published studies.
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