A diet focused on whole plant foods is a critical determinant of healthy aging.
Among the countless bioactive compounds in plants, flavonoids have received considerable attention in recent years for their influence on health.
Research suggests, for example, that a high intake of these protective phytochemicals can guard against cardiovascular disease, Type 2 diabetes, certain cancers, cognitive decline and dementia.
Now, new study findings add to mounting evidence for flavonoids’ healthy-aging benefits.
The findings suggest that a high flavonoid diet – and a regular intake of specific flavonoid-rich foods – can lower the risks of developing frailty, impaired physical function and poor mental health in our 70s and beyond.
What are flavonoids?
Flavonoids are a large family of more than 5,000 phytochemicals in fruits, vegetables and other plant foods. Dietary flavonoids are categorized into six subclasses, each one residing in certain foods and having specific health properties.
The subclasses are anthocyanins (berries, red grapes, plums, red cabbage), flavan-3-ols (green and black tea, cocoa), flavonols (onions, kale, arugula, watercress), flavanones (citrus fruit), flavones (parsley, thyme, celery) and isoflavones (soybeans, lentils, chickpeas).
About the latest research
The study, published last month in the American Journal of Clinical Nutrition, investigated the relationship between intake of flavonoids and flavonoid-rich foods and frailty, impaired physical function and poor mental health, indicators of unhealthy aging.
The research team analyzed data from two U.S. studies: the Nurses’ Health Study (females) and the Health Professionals Follow-up Study (males). A total of 62,743 women and 23,687 men, ages 60 and older, were followed for 24 and 12 years, respectively.
Information on age, body measurements, lifestyle behaviours, medication use, family medical history and recent personal health diagnoses was collected every two years.
Participants provided detailed dietary information at baseline and every four years thereafter. A “flavodiet” score was calculated for each participant by adding up intakes (servings/day) of key food contributors to total flavonoid intake.
Key flavonoid-rich foods included blueberries, strawberries, grapes, raisins, apples, oranges, orange juice, grapefruit, grapefruit juice, tea, red wine, onion and sweet bell peppers.
Frailty, measured every four years, was defined as having at least three of five criteria: fatigue, poor strength, reduced aerobic capacity, at least five chronic illnesses and a weight loss of five per cent or more.
Participants reported perceived physical limitations in basic mobility, daily living tasks and performing various moderate and vigorous activities. They were also asked about symptoms of depression, anxiety and overall well-being.
High flavodiet scores protective
Among participants in the Nurses’ Health Study, those with the highest flavodiet scores had a 15 per cent lower risk of developing frailty, a 12 per cent lower risk of developing impaired physical function and a 12 per cent lower risk of developing poor mental health during the study period compared to women with the lowest flavodiet scores.
The highest intakes of tea, red wine, apples, blueberries, strawberries, oranges and orange juice – and increased intakes of these foods over the study period – were associated with a lower risk of all three outcomes in women.
Surprisingly, fewer protective effects were seen in men.
Participants in Health Professionals Follow-up Study with the highest (versus lowest) flavodiet scores were 18 per cent less likely to have poor mental health scores.
Higher intakes of tea and blueberries were tied to a lower risk of poor mental health. Intakes of key flavonoid-rich foods were not associated with risk of frailty or impaired physical function.
It’s unclear if there are differences in diet-related risks factors for health in aging between males and females. The findings in men may also have been influenced by the shorter follow-up of 12 years, resulting in fewer outcomes being reported.
The researchers also found that a daily increase of three servings of flavonoid-rich foods and beverages during the study translated to a 6 to 11 per cent lower risk across all three outcomes in females and a 15 per cent lower risk of poor mental health in males.
To arrive at their findings, the researchers accounted for other influential factors including age, smoking status, family health history, personal health, physical activity, body mass index and calorie intake.
How flavonoids safeguard healthy aging
The new findings are in keeping with previous studies linking high intakes of flavonoids or flavonoid-rich foods to a lower risk of frailty, impaired physical function and depression.
Flavonoids’ strong antioxidant and anti-inflammatory effects are thought to protect cells from damage caused by oxidative stress and inflammation, factors that accumulate during aging.
Elevated levels of inflammation can lead to loss of muscle mass and strength.
Inflammatory immune compounds can also communicate with the brain, affecting mood and energy levels.
Takeaway
The findings suggest a modest, yet doable, dietary adjustment – increasing your daily intake of flavonoid-rich foods by three servings – can optimize healthy aging and quality of life.
One serving is equivalent to one half-cup of blueberries, strawberries or grapes, one ounce of raisins, one whole orange or apple, one half of a grapefruit, five ounces of citrus fruit juice, eight ounces of tea, one slice of raw onion or one half-cup cooked or one-quarter of a small bell pepper.
Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan. Follow her on X @LeslieBeckRD
