Dietary intake, body composition, and muscle function in resistance-untrained strict vegetarian and non-vegetarian women: an exploratory cross-sectional study

Strict vegetarian and nonvegetarian diets may differ in quantity and quality of nutrient intake. This study aimed to compare dietary intake, lean mass, bone mineral content (BMC), bone mineral density (BMD), and muscle function between resistance-untrained strict vegetarians (SVs) and nonvegetarians (NVs) women. Seventy-one untrained women participated in this study, including 35 SV (28.2 ± 4.8 years) and 36 NV (29.6 ± 5.8 years). The SV group had adhered to their dietary pattern for 3.1 ± 2.1 years. Dietary intake was assessed using a 3-day food record, while total and regional lean mass, BMC, and BMD were measured by dual-energy X-ray absorptiometry. Muscle function was evaluated through knee extension peak torque (KEPT), knee flexion peak torque (KFPT) using an isokinetic dynamometer, and countermovement vertical jump (CMJ). No significant difference in total energy intake (<i>p</i> = 0.546) was observed between groups. However, SV participants had a higher carbohydrate intake (<i>p</i> = 0.001) and lower intakes of protein (<i>p</i> < 0.001), fat (<i>p</i> < 0.001), and calcium (<i>p</i> = 0.049). Calcium intake was below the recommended level for both groups (SV: 345.2 mg, NV: 421.9 mg; <i>p</i> < 0.001). Additionally, no significant differences (<i>p</i> > 0.05) were found between SV and NV in total or regional lean mass, BMC, BMD, KEPT, KFPT, and CMJ. Although SV consumed less protein, while still meeting minimum recommendations, total energy intake was similar between groups due to increased carbohydrate intake, supporting similar adaptations in lean mass, bone mineral content, bone mineral density, and muscle function. However, the observed calcium inadequacy highlights the need for nutritional counseling, particularly for strict vegetarians.