Oral Presentation 30th Australian and New Zealand Bone and Mineral Society Annual Scientific Meeting 2020

Higher dietary nitrate intake is associated with better muscle function in men and women independent of physical activity levels (#47)

Marc Sim 1 2 , Lauren C Blekkenhorst 1 2 , Nicola P Bondonno 2 3 , Simone Radavelli-Bagatini 2 , Peter Peeling 4 5 , Catherine P Bondonno 1 2 , Dianna J Magliano 6 7 , Jonathan Shaw 7 , Richard Woodman 8 , Kevin Murray 9 , Joshua R Lewis 1 2 10 , Robin M Daly 11 , Jonathan M Hodgson 1 2
  1. Medical School, The University Western Australia, Perth, Western Australia, Australia
  2. School of Medical & Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia
  3. School of Biomedical Science, The University Western Australia, Nedlands, Western Australia, Australia
  4. Western Australian Institute of Sport, Perth, Western Australia, Australia
  5. School of Human Sciences (Exercise and Sports Science), The University Western Australia, Perth, Western Australia, Australia
  6. School of Public Health and Preventive Medicine Melbourne, Monash University, Melbourne, Victoria, Australia
  7. Baker Heart and Diabetes Institute (HDI), Melbournce, Victoria, Australia
  8. Flinders Centre for Epidemiology and Biostatistics, Flinders University, Adelaide, South Australia, Australia
  9. School of Population and Global Health, The University Western Australia, Perth, WA, Australia
  10. Centre for Kidney Research, Children's Hospital at Westmead, The University of Sydney, Sydney, New South Wales, Australia
  11. Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, VIC, Australia

Introduction: Short-term, high-dosage nitrate supplements can improve vascular and muscle function, but whether higher habitual dietary nitrate is associated with better muscle function remains underexplored. We examined if habitual dietary nitrate intake is associated with better muscle function in a large cohort of men and women across the adult lifespan, and also whether the association was dependent on levels of physical activity.

Methods: The sample (n=3759) was drawn from the national population-based, Australian Diabetes, Obesity and Lifestyle (AusDiab) Study (56% female; mean±SD age 48.6 ± 11.1 y, range 25-85 y). Habitual dietary intake was assessed over 12 years by obtaining an average (at time-points 2000/01, 2004/05 and/or 2011/12) from a food frequency questionnaire. Nitrate intake was calculated from a validated nitrate database. Muscle function was quantified in 2011/12 by knee extension strength (KES) and the 8ft-timed-up-and-go (8ft-TUG) test. Physical activity was assessed by questionnaire (sedentary, <150 min/week, ≥150 min/week).

Results: Median (IQR) total nitrate intake was 65 (52-83) mg/day, with ~81% derived from vegetables. There were non-linear multivariable-adjusted dose-response relationships between total nitrate intake and both KES and 8ft-TUG (Figure 1). Individuals in the highest tertile of nitrate intake (median intake 91 mg/d) had 2.6 kg stronger KES (11%) and 0.24 sec faster 8ft-TUG (4%) compared to individuals in the lowest tertile of nitrate intake (median intake 47 mg/d; both p<0.05). Physical activity did not influence the relationship between nitrate intake and KES (p for interaction=0.864) or 8ft-TUG (p for interaction=0.997).

Conclusion: Higher habitual dietary nitrate intake, predominantly from vegetables, was associated with better long-term lower-limb muscle strength and physical function in men and women across the adult lifespan, independent of physical activity levels. Higher nitrate intake from vegetables may be an effective way to limit age-related declines in muscle function; a major contributor towards fall and fracture risk.

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