Skeletal muscle properties and vascular function do not differ between healthy, young vegan and omnivorous men

A vegan diet is associated with reduced cardiovascular morbidity and mortality, but protein deficiencies may be detrimental to skeletal muscle structure and function. The aim of this study was to compare the vascular and skeletal muscle properties between young, healthy, recreationally active habitual vegan (VEG) and omnivorous (OMN) men. Sixteen OMN and nine VEG underwent ultrasound scans to determine brachial artery flow-mediated dilation (FMD) and carotid artery intima-media thickness (cIMT) and vastus lateralis (VL) muscle thickness and fascicle pennation angle. Knee extension maximal voluntary isometric contraction (MVIC) force was assessed on an isokinetic dynamometer, and $$O_2max on a cycle ergometer and online gas analysis system. A three-day food diary determined habitual dietary behaviour. Bayesian analyses of independent groups provided "moderate" to "very strong" evidence for lower consumption of absolute (63±21 g/d vs. 98 ± 30 g/d; Bayes Factor (BF₀₁) = 0.140) and relative (0.86 ± 0.29 g/kg/d vs.1.36 ± 0.52 g/kg/d; BF₀₁ = 0.259) protein, absolute saturated fat (15.2 ± 7.9 g vs. 30.3 ± 11.8 g; BF₀₁ = 0.089) and cholesterol (5.0 ± 6.0 mg vs. 337.9 ± 232.6 mg; BF₀₁ = 0.019) in VEG compared to OMN, respectively. Further, there was "anecdotal" evidence to support no differences in FMD (3.37 ± 3.31% vs. 4.58 ± 5.82%; BF₀₁ = 2.591), cIMT (0.51 ± 0.07 mm vs. 0.49 ± 0.04 mm; BF₀₁ = 2.510), VL thickness (26.1 ± 3.7 mm vs. 27.8 ± 6.4 mm; BF₀₁ = 2.726), fascicle pennation angle (16.6 ± 4.7° vs. 17.7 ± 3.7°; BF₀₁ = 2.844), MVIC (627 ± 182 N vs. 551 ± 102 N; BF₀₁ = 1.656) or $$O_2max (40.8 ± 9.8 ml/kg/min vs. 35.8 ± 5.2 ml/kg/min; BF₀₁ = 1.218) between VEG and OMN, respectively. Despite marked differences in habitual nutrient intake, healthy, young vegan and omnivorous men did not differ regarding vascular and skeletal muscle structure and function, or cardiovascular fitness.