Title

Dietary nitrate intake is associated with muscle function in older women

Document Type

Journal Article

Publication Title

Journal of Cachexia, Sarcopenia and Muscle

ISSN

2190-6009

Volume

10

Issue

3

First Page

601

Last Page

610

PubMed ID

30907070

Publisher

John Wiley & Sons Ltd

School

School of Medical and Health Sciences

RAS ID

28085

Grant Number

NHMRC Number : 572604

Comments

Originally published as: Sim, M., Lewis, J. R., Blekkenhorst, L. C., Bondonno, C. P., Devine, A., Zhu, K., ... Hodgson, J. M. (2019). Higher dietary nitrate intake is associated with better muscle function in older women. Journal of Cachexia, Sarcopenia and Muscle, 10(3), 601-610. Original publication available here

Abstract

Background

In younger individuals, dietary nitrate supplementation has been shown to improve short‐term vascular and muscle function. The role of higher habitual nitrate intake as part of a typical diet on muscle function in ageing has not been investigated. A cross‐sectional study of relationships between dietary nitrate and measures of muscle function in older community‐dwelling Australian women (n = 1420, ≥70 years) was undertaken.

Methods

Participants completed a semi‐quantitative food frequency questionnaire assessing dietary intake over the previous year. Total nitrate from vegetables and non‐vegetable sources was calculated from a validated instrument that quantified the nitrate content of food recorded within the food frequency questionnaire. Handgrip strength and timed‐up‐and‐go (TUG) were assessed, representing muscle strength and physical function, respectively. Cut‐points for weak grip strength (<22 >kg) and slow TUG (>10.2 s) were selected due to their association with adverse outcomes. Linear and logistic regressions were used to examine the relationship between total nitrate intake and muscle function measures.

Results

Mean ± standard deviation (SD) total nitrate intake was 79.5 ± 31.2 mg/day, of which 84.5% came from vegetables. Across the unadjusted tertiles of nitrate intake (P= 0.027) and faster TUG (per second, β −0.27, P = 0.001). The proportion of women with weak grip strength (<22 >kg) or slow TUG (>10.2 s) was 61.0% and 36.9%, respectively. Each SD higher nitrate intake (31.2 mg/day) was associated with lower odds for weak grip strength (OR 0.84, 95% CI 0.74–0.95, P = 0.005) and slow TUG (OR 0.86, 95% CI 0.76–0.98, P = 0.021). Compared with women in the lowest tertile of nitrate intake, women in the highest nitrate intake tertile had lower odds for weak grip strength (OR 0.65, 95% CI 0.49–0.87, Ptrend=0.004) and slow TUG (OR 0.72, 95% CI 0.53–0.97, Ptrend = 0.044).

Conclusions

This investigation highlights potential benefits of nitrate‐rich diets on muscle strength and physical function in a large cohort of older women. Considering poor muscle strength and physical function is associated with a range of adverse health outcomes such as falling, fractures, cardiovascular disease, and mortality, increasing dietary nitrate, especially though vegetable consumption may be an effective way to limit age‐related declines in muscle function.

DOI

https://doi.org/10.1002/jcsm.12413

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