Improvements In Diet Quality Are Associated With Increased Amino Acid Metabolites Following Initial Military Training

Changes in serum metabolome profiles indicate increased rates of protein turnover may contribute to lean body mass (LBM) accretion during initial military training (IMT). Whether that response is associated with changes in dietary intake during IMT is unknown. PURPOSE: This study aimed to determine associations among changes in amino acid metabolites, body composition, diet quality, and dietary intake during 22-weeks of IMT. METHODS: Body composition (assessed by bioimpedance) and diet quality (Healthy Eating Score (HES)-7) were measured and serum was collected before (PRE) and after (POST) IMT in 116 male volunteers (22 ± 4 yr; BMI: 27 ± 6 kg/m2). Untargeted global metabolomic profiling was used to characterize the serum metabolome. A subset of volunteers (n = 32) completed a 24-hr dietary recall at both timepoints. RESULTS: LBM increased (mean change [95% CI]: 1.5 [0.9, 2.1] kg), fat mass decreased (-2.5 [-3.5,-1.5] kg), HES-7 improved (p < 0.001) as fruit, vegetable and whole grain consumption increased (p < 0.02), and intake of total energy, carbohydrates, fats, sugars, and micronutrients increased PRE to POST (n = 32, p < 0.05). Of the 220 identified amino acid metabolites, 49 (22%) significantly changed from PRE to POST (p < 0.05, Q < 0.01). Increases were observed in 36% of urea cycle metabolites, 14% of branched-chain amino acid (BCAA) metabolites, and 32% of histidine metabolites, supporting an increased rate of protein turnover. Increases in urea cycle metabolites and were associated with increased LBM (Spearman’s ρ: 0.21 to 0.23), total energy and iron (ρ: 0.36 to 0.70), and fruit and vegetable intake (ρ: 0.22 to 0.35, all p < 0.05). Increases in histidine metabolites were associated with increased fish and dairy intake (ρ: 0.31 to 0.38, p < 0.05). BCAA metabolites were inversely associated with carbohydrate and fiber intake (ρ: -0.36 to -0.49, p < 0.05). Changes in total body mass were inversely associated with changes in vegetable intake (ρ = -0.24, p < 0.05). CONCLUSION: Increased consumption of iron, fruits, vegetables, dairy and fish correlated with metabolic changes associated with LBM accretion suggesting improvements in diet intake may contribute to favorable changes in body composition during IMT. Funded by MRDC. Authors’ views not official U.S. Army or DoD policy. Supported by: Funded by MRDC