Tomlinson, DJ, Erskine, RM, Morse, CI and Onambélé, G (2018) Impact of Above-Average Proanabolic Nutrients Is Overridden by High Protein and Energy Intake in the Muscle-Tendon Unit Characteristics of Middle- to Older-Aged Adults. The Journal of Nutrition, 148 (11). pp. 1776-1785. ISSN 0022-3166

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Abstract

Background: The impact, within a single cohort, of independent modulators of skeletal muscle quality, including age, adiposity/obesity, habitual nutritional intake and physical activity (PA), is unclear. Objective: We examined the bivariate associations between age, adiposity, habitual nutritional intake and PA against 11 key intrinsic muscle-tendon unit (MTU) characteristics to identify the strongest predictors. We also compared overall profile differences between MTU categories using Z-scores illustrated in radar graphs. Method: Fifty untrained independent living males (n=15) and females (n=35) aged 43-80yrs (Mean±SD: 64±9yrs) were categorized by adiposity (Male: normal adiposity (NA) <28%; high adiposity (HA) ≥28%; Female: NA<40%; F HA≥40%) and BMI (Normal: BMI 18–<25; Overweight: BMI ≥25–<30; and Obese: BMI ≥ 30). Group differences were examined by body composition assessed using dual energy X-ray absorptiometry, habitual nutritional intake through a 3-day food diary, PA (work, leisure, sport) using the Baecke questionnaire, 14 serum cytokine concentrations using multiplex luminometry and 11 MTU characteristics of the gastrocnemius medialis using a combination of isokinetic dynamometry, electromyography, and ultrasonography. Results: Interestingly, classification by BMI highlighted differences between normal and obese individuals in 6/11 MTU characteristics (P<0.001-P=0.043). No statistical differences were reported in serum cytokine concentrations between adiposity/BMI classifications. BMI predicted 8/11 (r=0.62-0.31; P<0.001-P=0.032), daily energy intake predicted 7/11 (r=0.45-0.34; P=0.002-P=0.036), age predicted 5/11 (r=-0.49--0.32; P<0.001-P=0.032), work-based PA predicted 5/11 (r=0.43-0.32; P=0.003-P=0.048) and adiposity predicted 4/11 (r=0.51-0.33; P<0.001-P=0.022) MTU characteristics. Mathematical Z-scores and radar graphs illustrated how endocrine and dietary profiles but not PA differed between top and bottom ~20% muscle unit size and specific force. Conclusion: Given the number of factors associated with the MTU, education should be targeted to both adequate food quantity and quality (especially protein intake) and increasing habitual moderate to vigorous PA, whilst decreasing sedentary behavior. Specific endocrine parameters are also proposed as key pharmaceutical targets.

Item Type:	Article
Uncontrolled Keywords:	1111 Nutrition And Dietetics, 0702 Animal Production, 0908 Food Sciences
Subjects:	T Technology > TX Home economics > TX341 Nutrition. Foods and food supply R Medicine > RC Internal medicine > RC1200 Sports Medicine
Divisions:	Sport & Exercise Sciences
Publisher:	American Society for Nutrition
Date Deposited:	19 Jul 2018 10:07
Last Modified:	05 Nov 2021 11:15
DOI or ID number:	10.1093/jn/nxy185
Editors:	Davis, T
URI:	https://researchonline.ljmu.ac.uk/id/eprint/8980

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