Flavonoids belong to a class of polyphenolic compounds found in large quantities in plant-based diets. They are known for their antioxidant and anti-inflammatory properties, which contribute to various health benefits. These compounds are present in various food items, including fruits, vegetables, tea, and wine. They are divided into several subclasses, such as anthocyanins, flavan-3-ols, flavones, and flavanones.
Many research studies have reported that consuming more flavonoids is associated with a lower risk of chronic illnesses and death. However, most of these studies have noted the quantity of flavonoids consumed. However, limited research has explored the role of flavonoid diversity, or the number of distinct flavonoids and foods high in flavonoid levels that are consumed. This study attempts to close the gap by investigating the relationship between the risk of several chronic diseases and all-cause mortality and the diversity of dietary flavonoid intake.
Researchers suggest that a greater diversity of dietary flavonoids may provide better health protection than a limited diversity of flavonoids because different flavonoid compounds have biological advantages. This large-scale prospective cohort study collects information from 124,805 participants aged 40 and above, using information from the UK Biobank. Dietary flavonoid intake was assessed using repeated 24-hour dietary recall questionnaires. The diversity of intake was measured using Hill’s numbers, a technique based on Shannon’s entropy, which considers the quantity of the various flavonoid compounds ingested.
Flavonoid diversity number from effective compounds taken daily and quantity (mg/day) basis were examined in the study, along with subclass-specific and food-specific diversity. The diversity of flavonoid intake was determined by converting entropy from Shannon’s equation to Hill’s effective numbers. These effective numbers are used to translate Shannon’s non-linear score into a comprehensible diversity metric. Using the short form of the International Physical Activity Questionnaire, physical activity was determined. The sum of walking, moderate, and vigorous activity, assessed in metabolic equivalents, was used to calculate total physical activity.
The history of diabetes mellitus (type 1 or 2) and hypertension was obtained from ICD codes dated before the last day of the dietary assessment, as well as self-reported physician diagnoses of the condition. All outcomes of interest were examined in relation to the variety of flavonoid consumption using Cox proportional-hazards models.
Quintiles with low flavonoid diversity (Q1) as the reference group were used to predict flavonoid diversity. Models with and without interaction terms were compared using ratio tests to determine if the combined effect of flavonoid intake amount and diversity was greater (or less) than the sum of the individual effects. The quantity (quintiles) of the same flavonoids that influenced flavonoid diversity was mutually adjusted for in all models. The relationships were not impacted by participant diet (model 4) and medical history (model 5), which are adjusted for in addition to demographic and lifestyle characteristics (model 3).
The findings highlighted future recommendations that emphasize the importance of consuming flavonoids from a diverse range of food sources. The environmental footprints of various foods high in flavonoids are also investigated to ensure that consuming them promotes planetary health and environmental sustainability. The quantity and variety of dietary flavonoid consumption were associated with a decreased risk of death and chronic illnesses, according to this study.
Reference: Parmenter BH, Thompson AS, Bondonno NP, et al. High diversity of dietary flavonoid intake is associated with a lower risk of allcause mortality and major chronic diseases. Nat Food. doi:10.1038/s43016-025-01176-1
