Daily requirement for and splanchnic uptake of leucine in healthy adult Indians.
BACKGROUND
The 1985 FAO/WHO/UNU requirement for leucine is too low according to tracer-derived estimates of leucine oxidation and balance in adults from developed regions.


OBJECTIVE
The leucine requirement in populations in developing countries was assessed with use of the 24-h tracer balance method and on the basis of nitrogen balances.


METHODS
Twenty healthy Indian men were studied during their consumption for 6 d of 2 L-amino acid diets that supplied either 14 and 30 (n = 10) or 22 and 40 (n = 10) mg leucine x kg(-1) x d(-1) in random order. At 1800 on day 7, a 24-h constant intravenous [13C]leucine tracer-infusion protocol was conducted to determine leucine oxidation and daily leucine balance. During the intake of 40 mg leucine/d, [2H3]leucine was given orally to assess the splanchnic uptake of leucine.


RESULTS
Mean 24-h leucine oxidation rates were 29.8, 30.6, 33.6, and 39.3 mg x kg(-1) x d(-1) at leucine intakes of 14, 22, 30, and 40 mg x kg(-1) x d(-1), respectively; daily leucine balances were -16.5, -9.0, -3.3, and 0.5 mg x kg(-1) x d(-1), respectively. Mixed-models linear regression of balance against leucine intake resulted in a zero balance at a leucine intake of 37.3 mg x kg(-1) x d(-1). Nitrogen balances were -12.7, -17.9, -3.9, and 1.0 mg x kg(-1) x d(-1) at leucine intakes of 14, 22, 30, and 40 mg x kg(-1) x d(-1). Regression of nitrogen balance against intake resulted in a zero balance at a leucine intake of 37.6 mg x kg(-1) x d(-1). The first-pass splanchnic uptake of leucine was 45.7% and 33.9% in the fasted and fed periods, respectively.


CONCLUSIONS
A tentative mean leucine requirement of 40 mg x kg(-1) x d(-1) is proposed for healthy Indian adults, as it is for Western subjects.
Kurpad
A V
AV
Department of Physiology and Nutrition Research Center, St John's Medical College, Bangalore, India. a.kurpad@divnut.net
Raj
T
T
El-Khoury
A
A
Kuriyan
R
R
Maruthy
K
K
Borgonha
S
S
Chandukudlu
D
D
Regan
M M
MM
Young
V R
VR
D000328:Adult; D001944:Breath Tests; D002153:Calorimetry, Indirect; D002245:Carbon Dioxide / Q000032:analysis; D002247:Carbon Isotopes; D006801:Humans; D007194:India; D007262:Infusions, Intravenous; D007930:Leucine / Q000378:metabolism* / Q000493:pharmacokinetics; D008297:Male; D009584:Nitrogen / Q000378:metabolism*; D009751:Nutritional Requirements; D010084:Oxidation-Reduction; D012044:Regression Analysis; D014781:Viscera / Q000378:metabolism*
D002247:Carbon Isotopes; D002245:Carbon Dioxide; D007930:Leucine; D009584:Nitrogen