Dietary Nitrate Intake Is Positively Associated with Muscle Function in Men and Women Independent of Physical Activity Levels
- PMID: 33760920
- DOI: 10.1093/jn/nxaa415
Dietary Nitrate Intake Is Positively Associated with Muscle Function in Men and Women Independent of Physical Activity Levels
Abstract
Background: Nitrate supplements can improve vascular and muscle function. Whether higher habitual dietary nitrate is associated with better muscle function remains underexplored.
Objective: The aim was to examine whether habitual dietary nitrate intake is associated with better muscle function in a prospective cohort of men and women, and whether the relation was dependent on levels of physical activity.
Methods: The sample (n = 3759) was drawn from the Australian Diabetes, Obesity, and Lifestyle Study (AusDiab) (56% female; mean ± SD baseline age: 48.6 ± 11.1 y). Habitual dietary intake was assessed over 12 y by obtaining an average [of at least 2 time points, e.g., baseline (2000/2001) and 2004/2005 and/or 2011/2012] from a food-frequency questionnaire. Nitrate intake was calculated from a validated nitrate database and other published literature. Muscle function was quantified by knee extension strength (KES) and the 8-ft-timed-up-and-go (8ft-TUG) test performed in 2011/2012. Physical activity was assessed by questionnaire. Generalized linear models and logistic regression were used to analyze the data.
Results: Median (IQR) total nitrate intake was 65 (52-83) mg/d, with ∼81% derived from vegetables. Individuals in the highest tertile of nitrate intake (median intake: 91 mg/d) had 2.6 kg stronger KES (11%) and 0.24 s faster 8ft-TUG (4%) compared with individuals in the lowest tertile of nitrate intake (median intake: 47 mg/d; both P < 0.05). Similarly, individuals in the highest tertile of nitrate intake had lower odds for weak KES (adjusted OR: 0.69; 95% CI: 0.47, 0.73) and slow 8ft-TUG (adjusted OR: 0.63; 95% CI: 0.50, 0.78) compared with those in the lowest tertile. Physical activity did not influence the relationship between nitrate intake and muscle function (KES; P-interaction = 0.86; 8ft-TUG; P-interaction = 0.99).
Conclusions: Higher habitual dietary nitrate intake, predominantly from vegetables, could be an effective way to promote lower-limb muscle strength and physical function in men and women.
Keywords: healthy aging; muscle strength; nutrition; physical function; vegetables.
© The Author(s) 2021. Published by Oxford University Press on behalf of the American Society for Nutrition.
Comment in
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Gut Reaction: Habitual Dietary Nitrate Intake as a Modulator of Skeletal Muscle Contractile Function.J Nutr. 2021 May 11;151(5):1049-1050. doi: 10.1093/jn/nxab023. J Nutr. 2021. PMID: 33760918 Free PMC article. No abstract available.
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