Abstract
BACKGROUND: Lower antioxidant serum concentrations have been linked to declines in lean mass and physical function in older adults. Yet population data on the effect of dietary antioxidants on loss of muscle strength and physical function are lacking. OBJECTIVE: We sought to determine the association of antioxidant intake [vitamin C, vitamin E, and total and individual carotenoids (α-carotene, β-carotene, β-cryptoxanthin, lycopene, and lutein + zeaxanthin)] with annualized change in grip strength and gait speed in adults from the Framingham Offspring study. METHODS: This prospective cohort study included participants with a valid FFQ at the index examination and up to 2 prior examinations and at ≥2 measures of primary outcomes: grip strength (n = 2452) and/or gait speed (n = 2422) measured over 3 subsequent examinations. Annualized change in grip strength (kg/y) and change in gait speed (m/s/y) over the follow-up period were used. Linear regression was used to calculate β coefficients and P values, adjusting for covariates. RESULTS: Mean ± SD age of participants was 61 ± 9 y (range: 33-88 y). Median intakes (IQR, mg/d) of vitamin C, vitamin E, and total carotenoid across available examinations were 209.2 (133.1-394.2), 27.1 (7.4-199.0), and 15.3 (10.4-21.3), respectively. The mean follow-up time was ∼12 ± 2 y (range: 4.5-15.4 y). In the sex-combined sample, higher intakes of total carotenoids, lycopene, and lutein + zeaxanthin were associated with increased annualized change in grip strength [β (SE) per 10-mg higher intake/d, range: 0.0316 (0.0146) to 0.1223 (0.0603) kg/y)]. All antioxidants except for vitamin C were associated with faster gait speed [β (SE) per 10-mg higher intake/d, range: 0.00008 (0.00004) to 0.0187 (0.0081) m/s/y]. CONCLUSIONS: Higher antioxidant intake was associated with increase in grip strength and faster gait speed in this cohort of adults. This finding highlights the need for a randomized controlled trial of dietary antioxidants and their effect on muscle strength and physical function.