Relationship between essential amino acids and muscle mass, independent of habitual diets, in pre- and post-menopausal women
Marie-Eve Filion, Annie Fex, Antony D Karelis & M Aubertin-Leheudre
When it is limited the amount and quality of protein intake plays a role in determining the amount of skeletal muscle and the amount of essential amino acids (EAA) may be the primary determinant in this process. The purpose of this retrospective analysis was to examine the relationship between protein and EAA intake and the level of muscle mass in healthy omnivore (Om), vegan (Veg), and (OLV) Caucasian women. 21 Om, 22 OLV and 20 Veg were recruited. Women were sedentary, as assessed by questionnaire. Muscle mass (urinary creatinine), dietary intake (5-day dietary records), and biochemical analyses (urinary and plasma sex hormones) were obtained. We observed no significant difference between groups for muscle mass (P=0.214), EAA intake (P=0.206), leucine (P=0.111), isoleucine (P=0.263), age (P=0.439), and body mass index (P=0.133). However, we observed a significant difference between groups for total dietary protein intake (P=0.001), and total energy intake (P=0.012). These results were not influenced by the hormonal profile in each group (P ≥ 0.05 for plasma estrone, plasma estradiol, plasma testosterone and sex-hormone-binding-globulin). In conclusion, our results showed that the type of dietary protein habitually ingested (OM, OLV, or VEG) did not influence the level of muscle mass. Despite significant differences in total dietary protein (Om: 74 g/day versus OLV: 56 g/day versus Veg: 52 g/day), the intake of EAA (Om: 259 mg/kgBW per day versus OLV: 208 mg/kgBW per day versus Veg: 222 mg/kgBW per day) was not significantly different between groups indicating that EAA may be more important in determining the amount of muscle mass. Each of these eating patterns appears adequate to maintain muscle mass. These results are important because the loss of muscle mass is associated with functional limitations, falls and fractures. Thus, further studies need to focus on the role of the amount of EAA in muscle mass and in sarcopenia because the mechanisms leading to this phenomenon are still unknown.