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Cited by 122Muscle metabolism and nutritionNutrition and Health in AgingNutrition and Health Studies

The DOI matches its Crossref record; 59 of the 64 references it cites were found in a registry or an index.

Dietary Protein Requirement of Female Adults >65 Years Determined by the Indicator Amino Acid Oxidation Technique Is Higher Than Current Recommendations

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Rafii, Mahroukh, Chapman, Karen, Owens, Jillian, Elango, Rajavel, Campbell, Wayne W, Ball, Ronald O, Pencharz, Paul B, Courtney-Martin, Glenda·2015·The Journal of Nutrition
DOI 10.3945/jn.114.197517
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Abstract

Background Studies on protein requirements in vulnerable groups such as older adults are few, and results are conflicting.Objective The main objective of this study was to determine the protein requirements of free-living women >65 y by measuring the oxidation of l-[1-(13)C]phenylalanine to (13)CO2 in response to graded intakes of protein.Methods Twelve subjects participated in the study, with protein intakes ranging from 0.2 to 2.0 g · kg(-1) · d(-1) for a total of 82 studies. The diets provided energy at 1.5 times each subject's resting energy expenditure and were isocaloric. Protein was given as an amino acid mixture on the basis of the egg protein pattern, except for phenylalanine and tyrosine, which were maintained constant across the protein intake amounts. All subjects were adapted for 2 d before the study day to a protein intake of 1.0 g · kg(-1) · d(-1). The mean protein requirement was determined by applying a mixed-effects change-point regression analysis to F(13)CO2 (label tracer oxidation in (13)CO2 breath), which identified a breakpoint in the F(13)CO2 in response to graded amounts of protein.Results The mean estimated average requirement (EAR) and upper 95% CI (approximating the RDA) protein requirement of women >65 y were 0.96 and 1.29 g · kg(-1) · d(-1), respectively.Conclusion These estimates of protein requirements for older women are higher than the current EAR and RDA based on nitrogen balance data, which are 0.66 and 0.80 g · kg(-1) · d(-1), respectively. This trial was registered at clinicaltrials.gov as NCT01604980.

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Metadata

Authors
Rafii, M., Chapman, K., Owens, J., Elango, R., Campbell, W. W., Ball, R. O., Pencharz, P. B., & Courtney-Martin, G.
Affiliations
  • Hospital for Sick Children (CA)
  • University of British Columbia (CA)
  • Purdue University West Lafayette (US)
  • University of Alberta (CA)
ORCID
Venue
The Journal of Nutrition
Publisher
Elsevier BV
Published
2015-01
Volume
145
Issue
1
Pages
18-24
ISSN
0022-3166 (ISSN-L)
DOI
10.3945/jn.114.197517
OpenAlex
W2115817612
Cited by
122
References
64
Citations by year
2026: 4 · 2025: 9 · 2024: 8 · 2023: 11 · 2022: 11 · 2021: 7 · 2020: 11 · 2019: 7 · 2018: 17 · 2017: 12 · 2016: 18 · 2015: 5
FWCI
5.98
Type
journal article
Language
en
Open access
Licence
Locations
  • Journal of Nutrition (publishedVersion)
  • PubMed (publishedVersion)
Funders
  • Pfizer
  • Mead Johnson Nutrition
  • Hospital for Sick Children
  • Canadian Institutes of Health Research (MT10321)
Topics
  • Health Sciences › Nursing › Nutrition and Dietetics › Muscle metabolism and nutrition
  • Health Sciences › Medicine › Physiology (medical) › Nutrition and Health in Aging
  • Health Sciences › Medicine › Public Health, Environmental and Occupational Health › Nutrition and Health Studies
Keywords
protein requirements, older women, indicator amino acid oxidation, phenylalanine oxidation, nitrogen balance, estimated average requirement, RDA
MeSH terms
Age Factors, Aged, Aged, 80 and over, Amino Acids, Energy Intake, Carbon Isotopes, Dietary Proteins, Energy Metabolism, Female, Fluorine, Humans, Isotope Labeling, Nutritional Physiological Phenomena, Nutritional Requirements, Oxidation-Reduction, Phenylalanine, Tyrosine

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