Dietary carotenoids, flavonoids mitigate risk of frailty in old age

Sticking to a dietary pattern high in carotenoids and flavonoids during middle age helps prevent the development of frailty later in life, according to a study from Singapore.

Analysis of data from the population-based Singapore Chinese Health Study showed that over a mean follow-up of 20 years (mean age at baseline 51 years, mean age at follow-up 72 years), higher baseline consumption of carotenoids and flavonoids were associated with lower odds of physical frailty. [Nutr J 2025;24:188]

Compared with participants in the lowest intake quintile, those in the highest intake quintile had 31-percent and 20-percent reduced odds of physical frailty in later life for total carotenoids (median, 10.73 vs 3.24 mg/day; odds ratio [OR], 0.69, 95 percent confidence interval [CI], 0.55–0.85; p=0.001) and total flavonoids (median, 552.1 vs 34.5 mg/day; OR, 0.80, 95 percent CI, 0.64–0.99; p=0.019), respectively.

Looking at weakness and slowness within the physical frailty phenotype in later life, total carotenoid intake at baseline was inversely associated with weak handgrip strength (highest vs lowest intake quintile: OR, 0.60, 95 percent CI, 0.49–0.72; p=0.001). Meanwhile, total flavonoid intake at baseline was inversely associated with slow timed-up-and-go test performance (highest vs lowest intake quintile: OR, 0.83, 0.67–1.03; p=0.021).

When individual nutrients were assessed, significantly lower likelihood of physical frailty in later life was observed with the highest vs lowest baseline intake quartile of alpha-carotene (OR, 0.78, 95 percent CI, 0.63–0.95; p=0.037), beta-carotene (OR_, 0.65, 95 percent CI, 0.53–0.81; p<0.001), lutein (OR, 0.73, 95 percent CI, 0.59–0.90; p=0.003), flavan-3-ols (OR, 0.73, 95 percent CI, 0.59–0.91; p=0.014), and flavonols (OR, 0.75, 95 percent CI, 0.60–0.93; p=0.012).

“Although the exact mechanisms remain complex and not fully understood, the primary protective effects of carotenoids and flavonoids are likely attributable to their potent antioxidant and anti-inflammatory properties, since oxidative stress and inflammation are central to age-related loss of muscle and physical function,” the investigators explained. [J Cachexia Sarcopenia Muscle 2022;13:2772-2790; Am J Clin Nutr 2021;113:437-445]

Compounds that efficiently scavenge reactive oxygen species “may help mitigate or prevent mitochondrial and cellular damage caused by oxidative stress, as well as maintain protein homeostasis and skeletal muscle function, thereby protecting against age-related physical decline,” they added. [Clin Nutr Edinb Scotl 2006;25:444-453; Free Radic Biol Med 2019;132:58-66; Antioxidants Basel 2023;12:1063]

Describing the implications of their findings, the investigators stressed that public health programs should include interventions promoting a diet rich in carotenoids and flavonoids during midlife to mitigate the risk of physical frailty as people age.

Coloured fruits and vegetables—including green leafy vegetable, pumpkin and carrot, tomato, red paprika, and orange—are the major dietary source of carotenoids. On the other hand, flavonoids are widely distributed across various fruits, vegetables, plants, and herbs. Both compounds, depending on their subclasses, possess distinct chemical structures that affect their antioxidant activity, bioavailability, and metabolism. [Antioxidants 2022;11:795; J Nutr Biochem 2002;13:572-584]

“Future work should focus on identifying specific subclasses of carotenoids or flavonoids which may be beneficial for maintaining muscle strength and enhancing physical performance in older adults in interventional studies,” the investigators said.

The study involved 10,738 participants (58.3 percent female) who completed a validated 165-item semi-quantitative food frequency questionnaire at recruitment. Of these, 11.4 percent had physical frailty, assessed using a modified version of the Cardiovascular Health Study phenotype, at follow-up. Among the frail participants, 69.2 percent had weakness, 60.5 percent had slowness, 55.8 percent had exhaustion, and 39.4 percent had weight loss.

The investigators acknowledged several study limitations, including the absence of baseline assessment of physical frailty and the lack of data on the participants’ physical activity level at follow-up.