Document Detail

Threonine requirement of healthy adults, derived with a 24-h indicator amino acid balance technique.
MedLine Citation:
PMID:  11916756     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: Because we question the validity of the 1985 FAO/ WHO/UNU upper requirement for threonine of 7 mg x kg(-1) x d(-1), we proposed a tentative mean requirement of 15 mg x kg(-1) x d(-1). OBJECTIVE: Our goal was to assess threonine adequacy at 3 test intakes and the consequences of a 6-d compared with a 13-d dietary adaptation phase. DESIGN: We used a 24-h indicator amino acid balance technique ([1-(13)C]leucine as indicator) to assess the threonine requirement. Fifteen healthy adults were randomly assigned to receive 7, 15, or 46 mg threonine x kg(-1) x d(-1) and were studied after 6 and 13 d of adaptation to the experimental diets. Diets were based on an L-amino acid mixture in which the threonine content was varied. At 1700 on days 6 and 13, a 24-h intravenous [(13)C]leucine tracer infusion protocol was begun to assess leucine oxidation and daily leucine balances. RESULTS: There was no detectable effect of duration of dietary adaptation in leucine oxidation or balance, but the 24-h leucine oxidation and balances differed significantly between the 7-mg intake and each of the 2 higher intakes (P < 0.05). The latter were not significantly different. The 24-h leucine oxidation rate decreased across threonine intakes (P < 0.01 for main effect of diet, independent of infusion day). Leucine oxidation was highly correlated (r = 0.80) between the 2 dietary adaptation phases across all test intakes. CONCLUSION: The 1985 FAO/WHO/UNU threonine recommendation is inadequate, and 15 mg x kg(-1) x d(-1) is sufficient to achieve mean indicator (leucine) amino acid balance.
Sudhir Borgonha; Meredith M Regan; Seung-Ho Oh; Mervelina Condon; Vernon R Young
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Publication Detail:
Type:  Clinical Trial; Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American journal of clinical nutrition     Volume:  75     ISSN:  0002-9165     ISO Abbreviation:  Am. J. Clin. Nutr.     Publication Date:  2002 Apr 
Date Detail:
Created Date:  2002-03-27     Completed Date:  2002-04-23     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0376027     Medline TA:  Am J Clin Nutr     Country:  United States    
Other Details:
Languages:  eng     Pagination:  698-704     Citation Subset:  AIM; IM    
Laboratory of Human Nutrition, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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MeSH Terms
Leucine / blood,  metabolism
Nutritional Requirements
Radioactive Tracers
Threonine / administration & dosage,  blood,  metabolism*
Grant Support
Reg. No./Substance:
0/Radioactive Tracers; 61-90-5/Leucine; 72-19-5/Threonine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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