Flavonoid-rich foods lower risk of frailty and mental decline in older adults

Flavonoid-rich foods lower risk of frailty and mental decline in older adults

New research shows that adding foods richer in flavonoids, such as tea, berries and citrus fruits, to your diet could help reduce faintness and support mental and physical health as you age.

In a recently published study inThe American Journal of Clinical NutritionResearchers examined the associations between flavonoid intake and flavonoid-rich foods and unhealthy aging. Aging occurs due to the accumulation of cellular and molecular damage, leading to a gradual decline in mental and physical capabilities, increased susceptibility to disease, and eventual death. Despite the life expectancy, the proportion of years added in good health was constant.

In particular, diet is a key determinant of health in aging. Flavonoids are bioactive compounds found in plant-based foods that are drawing attention for their effects on healthy aging. Previous research has linked higher flavonoid intake to increased chances of healthy aging and a slowing of biological aging processes. Flavonoids are abundant in apples, tea, berries, citrus fruits, dark chocolate and red wine and exhibit oxidative stress reduction, anti-inflammatory and neuroprotective properties.

About the study

The Stealth Benefits of Tea: While blueberries and red wine grabbed headlines, tea intake showed consistent ties to lower risks in all three aging outcomes, even when consumed just 3 to 5 times weekly.

In the present study, researchers examined the associations between flavonoid intakes and flavonoid-rich foods and healthy aging indicators. They used data from the Follow-up Study (HPFS) and the Nurses Health Study (NHS). Participants in these cohorts completed medical history and lifestyle questionnaires at baseline and every two years thereafter.

Participants with missing data on dietary exposure and those with extreme energy intakes were excluded. Furthermore, food frequency questionnaires (FFQs) were completed at baseline and every subsequent four years. Intake frequencies of flavonoid-rich foods were recorded as servings per day, week, or month.

Both changes in intake and time-updated intake of the Flavodiet Score (FDS) and its components were calculated from the FFQs. The FDS, a total intake of major flavonoid-rich foods and beverages (particularly tea, apples, oranges, grapefruit, blueberries, strawberries, and red wine), was developed as a composite measure that captures a more composite measure of overall adherence to a dietary diet that allows for more flavonoid-rich foods and a cure-free perspective. In addition, time-updated recordings of total flavonoids and flavonoid subclasses were calculated from the FFQs. The study outcomes were frailty, poor mental health and physical impairments.

Participants completed the Short Form Health Survey (SF-36) every four years. Frailty was assessed from the SF-36 and defined as at least three of the following: fatigue, poor strength, reduced aerobic capacity, five or more chronic diseases, and weight loss of at least 5%. Likewise, a 100-point physical function score was calculated based on answers to 10 SF-36 questions. A score below 80 indicated physical impairment.

Mental health was assessed using five SF-36 questions (MF-5), the Center for Epidemiological Studies Depression Scale 10 in the NHS and the 15 questions in the Geriatric Depression Scale 15 in both the NHS and the HPF. Poor mental health was defined as an MF-5 score of 52 or less, a CES-D 10 score of 10 or higher, or a GDS-15 score of 6 or higher. COX proportional hazards models estimated associations with frailty, poor mental health and physical impairment.

Results

Lifestyle changes were important: Reducing flavonoid-rich food intake by over 7+ weekly servings increased the risk of frailty in women by 18%, suggesting that maintaining dietary habits is as important as improving them.

The study included 62,743 women from the NHS and 23,687 men from the HPFs. All participants were 60 years or older. In the NHS there were 11,369, 8,944 and 22,419 cases of frailty, poor mental health and physical impairment over 24 years of follow-up. In the HPFs, there were 1,957 cases of frailty, 4,165 physical impairments and 1,669 poor mental health over 12 years of follow-up.

In the NHS, the highest FDS were associated with a 15% reduced risk of frailty and a reduced risk of poor mental health and physical impairments. The highest intake of total flavonoids was associated with a lower risk of poor mental health and physical impairments and a 14% lower risk of frailty. The highest intakes of apples, red wine, tea, oranges/orange juice, and blueberries were associated with a lower risk of 11% to 21% than the lowest intakes.

The highest intakes of apples, blueberries, red wine, oranges/orange juice, and strawberries were associated with a reduced risk of physical impairment of 4% to 14% compared to the lowest intakes. Likewise, the highest intakes of strawberries, apples, grapefruit/grapefruit juice, and oranges/orange juice were associated with a 10% to 15% reduced risk of poor mental health compared to the lowest intakes.

There were fewer associations in the HPFs. Moderate (quintile 4) intake of total flavonoids was associated with a 12% lower risk of impaired physical function, although the highest Flavodiet score intake was associated with an 18% reduced risk of poor mental health. Additionally, moderate intake of red wine (quartile 3) and highest intake of blueberries and tea were associated with 29%, 15%, and 14% reduced risk of poor mental health, respectively.

Conversely, intake of any of the individual flavonoid-rich foods and beverages was not associated with frailty, physical impairment, or frailty in the HPFs. The highest intake of each flavonoid subclass was associated with a lower risk of frailty of 9%–17%, a lower risk of 8%–14%, and a lower risk of poor mental health (with the exception of flavan-3-OL monomers, which were not associated with poor mental health). Consistently fewer associations were observed in the HPFs; Moderate (quintile 4) intakes of flavan-3-ol polymers were associated with a 12% lower risk of developing impaired physical function, while moderate (quintiles 3 or 4) intakes of flavonols, flavan-3-OL polymers and flavones and high (quintiles 5) intakes of anthocyanins were associated with 16% -25%, among others 16% were associated.

FDS that decreased by seven or more servings per week were associated with a higher risk of physical impairment and frailty in the NHS by 7% and 18% respectively, and a higher risk of poor mental health in the HPFs by 60% compared to unchanged values. In addition, an increase in FD with three tri-services per day was associated with 8%, 7% and 11% lower risk of poor mental health, physical impairment and frailty in the NHS and 15% lower risk of poor mental health in the HPFs.

Conclusions

Not all subclasses are the same: flavan-3-ol monomers (in tea) had no mental health links, while anthocyanins (berries) and flavanones (citrus fruits) provided broad protective effects.

In sum, habitually high and increasing FDS were found to be associated with modest reductions in the risks of frailty, poor mental health and physical impairment in the NHS. Higher intakes of red wine, tea, oranges/orange juice, and blueberries in general were also typically associated with a lower risk of these outcomes. However, there were fewer associations in the HPFs. The paper suggests that this is due to factors such as the comparatively shorter follow-up time for men, resulting in fewer events and reduced statistical power, or differences in lifestyle factors such as smoking prevalence, indicating that further studies are needed to better understand whether potential sex differences in dietary risk factors for health may exist.

The authors also acknowledge several limitations, including the reliance on self-reported data that could lead to misclassification, the potential for residual or unmeasured confounders, the challenge of isolating the effects of flavonoids from other food components that are predominantly white, which could limit the generalizability of other groups' results.

Overall, the results suggest that high intakes of flavonoid-rich foods may support healthy aging. From a public health perspective, the observation that a modest and achievable increase, such as three additional servings per day of flavonoid-rich foods, with a significantly lower risk of these adverse aging outcomes in women (and of poor mental health in men) underscored the potential for simple dietary modifications to a legal lifespan.

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