Author(s): PAGE, J., STEBBINGS, G., MURPHY, C., KILDUFF, L., WALDRON, M., HEFFERNAN, S., Institution: SWANSEA UNIVERSITY, Country: UNITED KINGDOM, Abstract-ID: 1240

INTRODUCTION:
Growing interest in plant-based diets has fueled debate surrounding differences in dietary intake that could impact musculoskeletal (MSK) health and performance, such as protein, calcium and vitamin D [1]. Few studies have compared MSK properties of vegetarians (VEGT) and vegans (VEG). Early work, however, suggests muscle size and maximal strength in recreationally active male VEG is comparable to that of OMN [2] but bone mineral density (BMD) is lower and fracture risk greater compared with OMN [3]; although other studies show no differences [4]. This study aimed to compare dietary intake and musculoskeletal properties between habitual OMN, VEGT and VEG across the adult lifespan.
METHODS:
One hundred and fifty-one participants were recruited, in a cross-sectional observational design, having followed their chosen dietary pattern consecutively for > two years. Dietary patterns were self-reported and confirmed via food frequency questionnaires and a three-day weighed food diary. OMN (n=63, males=36, females=27, age=32 ±14 years, stature=1.75±0.08m, body mass=78.2±15.5kg), VEGT (n=24, males=4, females=20, age=36±15 years, stature=1.67±0.09m, body mass=67.4±17.7kg) and VEG (n=64, males=28, females=36, age=43±15 years, stature=1.71±0.08m, body mass=71.3±12.6kg) were assessed for body composition, femoral neck (FN) and total hip bone mineral density (BMD) via dual-energy X-ray absorptiometry. Vastus lateralis (VL) muscle thickness, anatomical (ACSA) and physiological cross-sectional area (PCSA), muscle volume and rectus femoris echo intensity (EI) were assessed via B-mode ultrasonography. Analysis of covariance was used (SPSS v29), controlling for age, sex, dietary adherence duration, self-report physical activity and body mass index, as appropriate.
RESULTS:
There were no differences between groups for skeletal muscle properties or body composition (P>0.05). Total hip BMD was lower in VEG compared with OMN (VEG=1.09±0.18g/cm2, OMN=1.24±0.18g/cm2; P=0.031), but not VEGT (1.13±0.14g/cm2, P>0.05) and there were no differences in FN BMD between groups (P>0.05). Both calcium and vitamin D intake were similar between groups (P>0.05); however, protein intake was higher in OMN (1.43±0.69 g/kg) compared with VEG (1.14±0.45 g/kg, P=0.029). Leucine intake was also greater in OMN (5697±3718 mg/d) compared with VEGT (2641±1360 mg/d, P= 0.001) and VEG (2405±1886 mg/d, P<0.001).
CONCLUSION:
This study found no differences between groups for muscle properties (thickness, ACSA, PCSA, volume or EI), despite lower intake of protein and important amino acids in the VEG and VEGT. Total hip BMD was lower in VEG compared to OMN, but is unlikely to be clinically relevant, nor were there differences in FN BMD between groups. There does not appear to be any beneficial or detrimental effects of plant-based diets on muscle or bone health.

References
1.Sobiecki et al., 2016,Nutr Res; 2.Page et al., 2021,Eur J Spor Sci; 3.Iguacel et al., 2018, Nutr Rev.; 4.Knurick et al., 2015,Nutrients.