Lysine requirements of healthy adult Indian subjects, measured by an indicator amino acid balance technique

• Published in: The American journal of clinical nutrition 2001-05, Vol.73 (5), p.900-907
• Main Authors: KURPAD, Anura V, RAJ, Tony, EL-KHOURY, Antoine, BEAUMIER, Louis, KURIYAN, Rebecca, SRIVATSA, Abhinash, BORGONHA, Sudhir, SELVARAJ, Ambalini, REGAN, Meredith M, YOUNG, Vernon R
• Format: Article
• Language: English
• Subjects: Adult; Amino acids; Amino Acids - metabolism; Biological and medical sciences; Breath Tests; Carbon Dioxide - analysis; Carbon Isotopes; European Continental Ancestry Group; Human physiology applied to population studies and life conditions. Human ecophysiology; Humans; India; Infusions, Intravenous; Lysine - administration & dosage; Lysine - blood; Lysine - metabolism; Male; Medical sciences; Men; Nutrition; Nutritional Requirements; Nutritional survey. Food supply and nutritional requirement; Oxidation; Oxidation-Reduction; Reference Values; Regression Analysis; Tropical medicine
• ISSN: 0002-9165; 1938-3207
• DOI: 10.1093/ajcn/73.5.900

In an earlier study, using a modification of the indicator amino acid oxidation approach, we concluded that the 1985 FAO/WHO/UNU-proposed lysine requirement of 12 mg x kg(-1) x d(-1) is likely inadequate to maintain body amino acid homeostasis in apparently healthy south Asian subjects and that our proposed requirement of 30 mg x kg(-1) x d(-1) is more appropriate. We assessed the lysine requirement in a similar population by using 4 test lysine intakes (12, 20, 28, and 36 mg x kg(-1) x d(-1)) with an indicator amino acid balance approach. Sixteen healthy male Indians were studied during each of 2 randomly assigned 8-d L-amino acid diets that supplied either 12 and 28 or 20 and 36 mg lysine. At 1800 on day 8, a 24-h intravenous [(13)C]leucine tracer-infusion protocol was conducted to assess leucine oxidation and daily leucine balance at each lysine intake. Mean 24-h leucine oxidation rates decreased significantly (P = 0.005) across different lysine intakes and were 104.1, 97.8, 87.3, and 87.3 mg x kg(-1) x d(-1) at intakes of 12, 20, 28, and 36 mg x kg(-1) x d(-1), respectively; mean 24-h leucine balances were 3.3, 9.1, 19.7, and 20.7 mg x kg(-1) x d(-1), respectively (P = 0.015, mixed-model analysis of variance). Oxidation and balances differed significantly between the lower and higher lysine intakes but were not significantly different between the 12- and 20-mg and 28- and 36-mg test intakes. Two-phase regression analysis indicated a mean breakpoint at 29 mg lysine x kg(-1) x d(-1) in the relation between lysine intake and leucine oxidation or balance. We propose a mean lysine requirement of 30 mg x kg(-1) x d(-1) for healthy Indian adults, which is the same amount we proposed previously for Western populations.