Onambele-Pearson G L
Manchester Metropolitan University, UK
Title: Diet quantity not quality, age and BMI are the most prolifi c predictors of skeletal muscle structural and functional characteristics in middle-age and older persons
Biography
Biography: Onambele-Pearson G L
Abstract
Statement of the Problem: The impact, within a single cohort, of independent modulators of skeletal muscle quality, including age, adiposity/obesity, nutrition and physical activity, is unclear. Methodology & Theoretical Orientation: Using a cross-sectional design, we examined the association between ageing, adiposity, nutrition and physical activity against intrinsic muscle-tendon unit (MTU) structural and functional characteristics. We hypothesised that: (1) Muscle-building nutrients intake would positively impacts on muscle quality; (2) the previously reported negative impact of high adiposity on older skeletal muscle quality, would increase the deleterious impact of ageing on skeletal muscle size and function; (3) high physical activity with low sedentary behaviour would positively impact MTU quality. Fifty untrained males (M=15) and females (F=35) aged 43-80 yrs old were categorised by adiposity (M = normal adipose <28%: high adipose ≥28%; F = normal adipose <40%: high adipose ≥40%) and body mass index (BMI) (Normal 18–24.9, Overweight (BMI 25–29.9) and Obese (BMI > 30)). Optimal diet quality, to achieve skeletal muscle synthesis and/or sparing in vivo, was theorized as a combination of: >1.2 g/day protein, >1.6 g/day omega 3 fatty acids, >10 g/day omega 6 fatty acids, >10 ug/day vitamin D and >3 mg/day vitamin E. Findings: Diet quality did not differ between subpopulations. Interestingly, optimal diet quality predicted 3/10, work-based physical activity and adiposity each predicted 4/10, age predicted 5/10, total calories predicted 7/10, whilst BMI predicted 8/10 skeletal muscle structural and functional characteristics. Only one maker of muscle function differed between low vs. high adipose persons (p=0.015). BMI however differentiated normal weight and obese individuals in 6/10 MTU characteristics (p<0.043). Conclusion & Significance: MTU ‘optimization focused lifestyle interventions’ should target education regarding adequate food quantity intake, whilst aiming also to increase habitual moderate-to-vigorous physical activity, particularly in high BMI middle-age to older individuals.