%0 Journal Article
%T Total sulfur amino acid requirements are higher during late gestation compared with early gestation in healthy Canadian pregnancies in a repeated-measures trial.
%A Scherbinsky K
%A Rasmussen BF
%A Li B
%A Kong D
%A Ball RO
%A Pencharz PB
%A Courtney-Martin G
%A Elango R
%J Am J Clin Nutr
%V 0
%N 0
%D 2024 Aug 10
%M 39128498
%F 8.472
%R 10.1016/j.ajcnut.2024.07.034
%X <B>BACKGROUND: </B>Dietary Reference Intake (DRI) Recommendations for total sulfur amino acids (TSAAs; methionine + cysteine) during pregnancy are based on factorial calculations using data from adult males. To date, no data exist on TSAA requirements obtained directly during pregnancy.<BR><B>OBJECTIVE: </B>The objective of this study was to examine whether TSAA requirements during early (11-20 wk) and late (31-40 wk) gestation in healthy females with singleton pregnancies are different than current recommendations, and different between early and late gestation using the indicator amino acid oxidation (IAAO) technique.<BR><B>METHODS: </B>Twenty-five females 20-40 y with a healthy singleton pregnancy were studied using the IAAO technique in a repeated measures design for a total of 70, 8-h d. On each study day a methionine test intake (range: 0-40 mg⋅kg-1⋅d-1) was provided in 8 hourly, isonitrogenous and isocaloric meals with cysteine excluded from the diet. Breath samples were collected at baseline and isotopic steady state of orally provided L-1-13C-Phenylalanine for measurement of phenylalanine oxidation. The requirement was determined using biphasic linear regression crossover analysis to identify a breakpoint in 13CO2 production, representing the estimated average requirement (EAR).<BR><B>RESULTS: </B>The TSAA requirement in healthy pregnant participants in early gestation was 11.1 mg⋅kg-1⋅d-1 {R2m = 0.79, R2c = 0.79; 95% confidence interval [CI] (8.9, 13.3 mg⋅kg-1⋅d-1)} and 15.0 mg⋅kg-1⋅d-1 (R2m = 0.72, R2c = 0.79; 95% CI [13.0, 17.0 mg⋅kg-1⋅d-1]) in late gestation. The difference between confidence intervals of the 2 breakpoints was = -3.9 ± 3.0, and statistically different.<BR><B>CONCLUSIONS: </B>We directly measured TSAA requirements in healthy pregnant mothers, and our findings suggest that requirements are lower than current DRI recommendations of 20 and 25 mg⋅kg-1⋅d-1, as the EAR, and Recommended Dietary Allowance, respectively. Late gestation TSAA needs are significantly different and increased 35% compared with early gestation. Recommendations for TSAA intake need to be tailored for gestational stage. This clinical trial was registered at clinicaltrials.gov as NCT04326322.