BACKGROUND: The current Dietary Reference Intake (DRI) recommendations for lysine requirements in children are based on a factorial estimate. OBJECTIVE: The objective of the current study was to determine the lysine requirement in healthy school-age children by measuring the oxidation of l-[1-(13)C]phenylalanine to (13)CO(2) (F(13)CO(2)) in response to graded intakes of lysine. DESIGN: Five healthy school-age children randomly received each of 7 lysine intakes (5, 15, 25, 35 50, 65, and 80 mg x kg(-1) x d(-1)) along with an amino acid mixture to give a final calculated protein intake of 1.5 g x kg(-1) x d(-1) and an energy intake of 1.7 x resting energy expenditure (REE). The mean lysine requirement was determined by applying 2-phase linear regression crossover analysis on F(13)CO(2) data, which identified a breakpoint (requirement) at minimal F(13)CO(2) in response to graded lysine intakes. RESULTS: The mean and population-safe (upper 95% CI) lysine requirements were determined to be 35 and 58 mg x kg(-1) x d(-1), respectively. CONCLUSIONS: The mean and population-safe lysine requirements for children are similar to those for adults (36 and 52 mg x kg(-1) x d(-1), respectively), which suggests that the findings from the current study reflect predominantly the maintenance lysine requirements in children and not all requirements for growth. Therefore, to ensure age-appropriate growth in school-age children, we propose the addition of the requirement of lysine for growth (approximately 6 mg x kg(-1) x d(-1)) to the mean estimate. The new mean and population-safe lysine requirements are 41 and 58 mg x kg(-1) x d(-1), respectively; these values are significantly higher than the current DRIs of 37 and 46 mg x kg(-1) x d(-1), respectively.
BACKGROUND: The current Dietary Reference Intake (DRI) recommendations for lysine requirements in children are based on a factorial estimate. OBJECTIVE: The objective of the current study was to determine the lysine requirement in healthy school-age children by measuring the oxidation of l-[1-(13)C]phenylalanine to (13)CO(2) (F(13)CO(2)) in response to graded intakes of lysine. DESIGN: Five healthy school-age children randomly received each of 7 lysine intakes (5, 15, 25, 35 50, 65, and 80 mg x kg(-1) x d(-1)) along with an amino acid mixture to give a final calculated protein intake of 1.5 g x kg(-1) x d(-1) and an energy intake of 1.7 x resting energy expenditure (REE). The mean lysine requirement was determined by applying 2-phase linear regression crossover analysis on F(13)CO(2) data, which identified a breakpoint (requirement) at minimal F(13)CO(2) in response to graded lysine intakes. RESULTS: The mean and population-safe (upper 95% CI) lysine requirements were determined to be 35 and 58 mg x kg(-1) x d(-1), respectively. CONCLUSIONS: The mean and population-safe lysine requirements for children are similar to those for adults (36 and 52 mg x kg(-1) x d(-1), respectively), which suggests that the findings from the current study reflect predominantly the maintenance lysine requirements in children and not all requirements for growth. Therefore, to ensure age-appropriate growth in school-age children, we propose the addition of the requirement of lysine for growth (approximately 6 mg x kg(-1) x d(-1)) to the mean estimate. The new mean and population-safe lysine requirements are 41 and 58 mg x kg(-1) x d(-1), respectively; these values are significantly higher than the current DRIs of 37 and 46 mg x kg(-1) x d(-1), respectively.
Authors: Minghua Tang; George P McCabe; Rajavel Elango; Paul B Pencharz; Ronald O Ball; Wayne W Campbell Journal: Am J Clin Nutr Date: 2014-01-15 Impact factor: 7.045
Authors: Alex J Thompson; Claire D Bourke; Ruairi C Robertson; Nirupama Shivakumar; Christine A Edwards; Tom Preston; Elaine Holmes; Paul Kelly; Gary Frost; Douglas J Morrison Journal: Gut Date: 2021-06-08 Impact factor: 23.059