1
|
Rafii M, Paoletti A, He H, Porto B, Szwiega S, Pencharz PB, Ball RO, Kong D, Xu L, Elango R, Courtney-Martin G. Dietary Lysine Requirements of Older Adults Stratified by Age and Sex. J Nutr 2024; 154:2133-2142. [PMID: 38735574 DOI: 10.1016/j.tjnut.2024.04.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 04/17/2024] [Accepted: 04/26/2024] [Indexed: 05/14/2024] Open
Abstract
BACKGROUND Current recommendation for lysine in older adults, 30 mg/kg/d, is based on young adult data. Evidence suggests that amino acid requirements may differ between young and old adults with both sex and age having an effect in the elderly. OBJECTIVES This study aimed to define the lysine requirements in healthy older adults using the indicator amino acid oxidation (IAAO) method with L-[1-13C] phenylalanine as the indicator and to compare the derived estimates based on age: 60-69 y and >70 y. METHODS Fourteen healthy males and 16 healthy females [>60 y, body mass index (BMI) = 26.3 kg/m2] were randomly assigned to receive 3-7 lysine intakes from 10 to 80 mg/kg/d. Subjects were adapted to a standard liquid diet providing 1.0 g/kg/d protein and adequate energy, for 2 d, with indicator oxidation measurements performed on day 3. The rate of release of 13CO2 from the oxidation of L-[1-13C] phenylalanine was measured in breath. A 2-phase linear mixed-effect model, and parametric bootstrap were used to determine mean lysine requirements and the 95% confidence intervals (CIs). The overlap of the 95% CI between the 2 age groups were used to compare the requirement estimates. The null hypothesis was accepted if the interval contained zero. RESULTS The mean and upper 95% CI of the lysine requirement for females were 32.9 and 40.9 and 46.2 and 53.7 mg/kg/d for those aged 60-69 y and >70 y, respectively. The mean and upper 95% CI of the lysine requirement for the 2 groups of males were not different so was combined to yield a mean and 95% CI of 32.2 and 38.2 mg/kg/d. CONCLUSIONS To our knowledge, this is the first study to report on the lysine requirement in adults aged >60 y. These results provide a basis from which the adequacy of diets to meet lysine needs of older adults can be assessed. The trial was registered at clinicaltrials.gov as NCT02008955 (https://clinicaltrials.gov/study/NCT02008955).
Collapse
Affiliation(s)
- Mahroukh Rafii
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Alyssa Paoletti
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Henry He
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Beatriz Porto
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Sylwia Szwiega
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Paul B Pencharz
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada; Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada; Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Ronald O Ball
- Department of Agriculture, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Dehan Kong
- Department of Statistical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Libai Xu
- School of Mathematical Sciences, Soochow University, Suzhou, Jiangsu, China
| | - Rajavel Elango
- Department of Pediatrics, School of Population and Public Health, University of British Columbia, Vancouver, British Columbia, Canada; BC Children's Hospital Research Institute, BC Children's Hospital, Vancouver, British Columbia, Canada
| | - Glenda Courtney-Martin
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada; Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada.
| |
Collapse
|
2
|
Paoletti A, Pencharz PB, Rafii M, Tomlinson C, Kong D, Xu L, Elango R, Courtney-Martin G. Protein intake affects erythrocyte glutathione synthesis in healthy adults aged ≥60 years in a repeated-measures trial. Am J Clin Nutr 2024; 119:917-926. [PMID: 38325765 DOI: 10.1016/j.ajcnut.2024.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 01/22/2024] [Accepted: 02/01/2024] [Indexed: 02/09/2024] Open
Abstract
BACKGROUND Protein recommendations for older adults are based on nitrogen balance data from young adults. Physiological studies using the indicator amino acid oxidation method suggest they need 30% to 50% more protein than current recommendations. We herein present glutathione (GSH) as a physiological estimate of protein adequacy in older adults. OBJECTIVES The objective was to measure GSH kinetics in response to varying protein intakes in a repeated-measures design in healthy adults aged ≥60 y using the precursor-product method. METHODS Sixteen healthy older adults (n = 8 male and n = 8 female; body mass index ≤30 kg/m2) were studied. Each received 4 of 6 protein intakes in random order (0.66, 0.8, 0.9, 1.1, 1.3 and 1.5 g⋅kg-1⋅d-1). At each intake level, participants underwent isotope infusion studies of 7 h duration following a 3-d adaptation to the test level of protein. On the fourth day, GSH fractional (FSR) and absolute synthesis (ASR) rates were quantified by measuring the incorporation of U-[13C2-15N]glycine into GSH at isotopic steady state. A mixed-effect change-point regression model was used to determine a breakpoint in FSR and ASR. Secondary outcomes included plasma concentrations of oxidative stress markers, homocysteine, 5-L-oxoproline (5-OP), and urinary sulfate. The effect of secondary outcomes on GSH kinetics was analyzed using a joint linear mixed-effect model and Tukey's post hoc test. RESULTS A protein intake of 1.08 g⋅kg-1⋅d-1 (95% confidence interval [CI]: 0.83, 1.32; Rm2 = 0.207; Rc2 = 0.671; P < 0.001) maximized GSH FSR. There was no effect of protein intake on concentrations of erythrocyte GSH, plasma homocysteine, oxidative stress markers, or 5-OP (P > 0.05). Protein intake had a positive effect on urinary sulfate excretion (P < 0.0001). CONCLUSION A protein intake of 1.08 g⋅kg-1⋅d-1 from a high-quality protein maximized GSH synthesis in adults ≥60 y. This lends support to data suggesting a requirement higher than the current recommendation. This study was registered at clinicaltrials.gov as NCT02971046.
Collapse
Affiliation(s)
- Alyssa Paoletti
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada; Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Paul B Pencharz
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada; Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada; Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Mahroukh Rafii
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Christopher Tomlinson
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada; Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada; Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Dehan Kong
- Department of Statistical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Libai Xu
- School of Mathematical Sciences, Soochow University, Jiangsu Province, China
| | - Rajavel Elango
- Department of Pediatrics, School of Population and Public Health, University of British Columbia, Vancouver, British Columbia, Canada; BC Children's Hospital Research Institute, BC Children's Hospital, Vancouver, British Columbia, Canada
| | - Glenda Courtney-Martin
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada; Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada.
| |
Collapse
|
3
|
Paoletti A, Pencharz PB, Ball RO, Kong D, Xu L, Elango R, Courtney-Martin G. The Minimum Methionine Requirement for Adults Aged ≥60 Years Is the Same in Males and Females. Nutrients 2023; 15:4112. [PMID: 37836396 PMCID: PMC10574673 DOI: 10.3390/nu15194112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 09/18/2023] [Accepted: 09/21/2023] [Indexed: 10/15/2023] Open
Abstract
The minimum methionine requirement in the presence of excess dietary cysteine has not been determined in older adults. This study aimed to determine the minimum methionine requirement in healthy older adults using the indicator amino acid oxidation (IAAO) method. Fifteen healthy adults ≥ 60 years of age received seven methionine intakes (0 to 20 mg/kg/d) plus excess dietary cysteine (40 mg/kg/d). Oxidation of the indicator, L-[1-13C]phenylalanine (F13CO2), was used to estimate the mean minimum methionine requirement using a change-point mixed-effect model. There was no statistical difference between male and female requirement estimates, so the data were pooled to generate a mean of 5.1 mg/kg/d (Rm2 = 0.46, Rc2 = 0.77; p < 0.01; 95% CI: 3.67, 6.53 mg/kg/d). This is the first study to estimate the minimum methionine requirement in healthy older adults, which is the same between the sexes and as our lab's previous estimate in young adults. The findings are relevant considering current recommendations for increased consumption of plant foods, which will help to establish the appropriate balance of methionine and cysteine intake required to satisfy the sulphur amino acid requirements of older adults.
Collapse
Affiliation(s)
- Alyssa Paoletti
- Research Institute, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada; (A.P.); (P.B.P.)
- Department of Nutritional Sciences, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Paul B. Pencharz
- Research Institute, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada; (A.P.); (P.B.P.)
- Department of Nutritional Sciences, University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Pediatrics, University of Toronto, Toronto, ON M5S 1X8, Canada
| | - Ronald O. Ball
- Department of Agriculture, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada;
| | - Dehan Kong
- Department of Statistical Sciences, University of Toronto, Toronto, ON M5S 1X6, Canada;
| | - Libai Xu
- School of Mathematical Sciences, Soochow University, Suzhou 215006, China;
| | - Rajavel Elango
- Department of Pediatrics, School of Population and Public Health, University of British Columbia, Vancouver, BC V6H 0B3, Canada;
- British Columbia Children’s Hospital Research Institute, British Columbia Children’s Hospital, Vancouver, BC V6H 3N1, Canada
| | - Glenda Courtney-Martin
- Research Institute, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada; (A.P.); (P.B.P.)
- Department of Nutritional Sciences, University of Toronto, Toronto, ON M5S 1A8, Canada
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, ON M5S 3J7, Canada
| |
Collapse
|
4
|
Paoletti A, Pencharz PB, Ball RO, Kong D, Xu L, Elango R, Courtney-Martin G. The dietary requirement for total sulfur amino acids in adults aged ≥60 years appears to be higher in males than in females. Am J Clin Nutr 2023; 118:538-548. [PMID: 37356549 DOI: 10.1016/j.ajcnut.2023.06.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 05/09/2023] [Accepted: 06/22/2023] [Indexed: 06/27/2023] Open
Abstract
BACKGROUND The total sulfur amino acid (TSAA) recommendation in older adults is based on data from young adults. Physiological evidence suggests that older adults have a higher requirement than young adults. OBJECTIVES The objective of this study was to determine the TSAA requirement in healthy men and women aged ≥60 y. METHODS The TSAA requirement was determined using the indicator amino acid oxidation method with L-[1-13C]phenylalanine as the indicator. At recruitment, 15 older adults (n = 7 men and n = 8 women; BMI < 30 kg/m2) were assigned to receive 7 methionine intakes (5, 10, 15, 19, 25, 35, and 40 mg/kg/d) without dietary cysteine. Intake levels were randomly assigned to each subject. Following enrollment, 2 subjects completed 2 intakes and 3 completed 3, while the remainder completed all 7. Mean TSAA requirement was determined from oxidation of L-[1-13C]phenylalanine using a mixed-effect change-point model. The 95% CI was calculated using parametric bootstrap. To test whether breakpoints were different between men and women, the overlap in the 95% CI was calculated. RESULTS The mean TSAA requirement was 26.2 (Rm2 = 0.39, Rc2 = 0.89; P < 0.001) and 17.1 mg/kg/d (Rm2 = 0.22, Rc2 = 0.79; P < 0.001) for men and women, respectively. The requirement was significantly higher in men than in women (difference in CI: 9.1 ± 8.85). CONCLUSIONS To our knowledge, this is the first study to determine the TSAA requirement in older adults. The requirement in older women is similar to current recommendations but is 75% higher in older men. These findings are important given recommendations for increased plant protein consumption. They will help in the assessment of diet quality and provide the basis of dietary guidelines for older adults consuming a plant-based diet. This trial was registered at clinicaltrials.gov as NCT04595188.
Collapse
Affiliation(s)
- Alyssa Paoletti
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Paul B Pencharz
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada; Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada; Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Ronald O Ball
- Department of Agriculture, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Dehan Kong
- Department of Statistical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Libai Xu
- Department of Statistical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Rajavel Elango
- Department of Pediatrics, School of Population and Public Health, University of British Columbia, Vancouver, British Columbia, Canada; BC Children's Hospital Research Institute, BC Children's Hospital, Vancouver, British Columbia, Canada
| | - Glenda Courtney-Martin
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada; Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada.
| |
Collapse
|
5
|
Pezzali JG, Rafii M, Courtney-Martin G, Cant JP, Shoveller AK. Applying the indicator amino acid oxidation technique in the domestic cat: results of a pilot study and development of a non-steady state prediction model. J Anim Sci 2023; 101:skac390. [PMID: 36434784 PMCID: PMC10007698 DOI: 10.1093/jas/skac390] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 11/23/2022] [Indexed: 11/27/2022] Open
Abstract
The aim of this study was to evaluate whether the indicator amino acid oxidation (IAAO) method could be applied in the domestic cat. Six adult male cats were used in a replicated 3 × 3 Latin square design. Three semi-synthetic diets were developed: a methionine (Met) and total sulfur AA (TSAA) deficient diet (T-BASAL; 0.24% Met+Cys - DM basis) and two Met and TSAA-sufficient diets in which either dl-Met (T-DLM) or 2-hydroxy-4-(methylthio)-butanoic acid (T-MHA) were supplemented, respectively, on an equimolar basis to meet the TSAA requirement (0.34%). After a 2-d diet adaptation, IAAO studies were performed. Cats were offered 13 small meals. The sixth meal contained a priming dose (4.8 mg/kg-BW) of l-[1-13C]-Phe and the remaining meals a constant dose (1.04 mg/kg-BW). Breath samples were collected every 25 min to measure 13CO2 enrichment. The following morning, fasted blood samples were collected. Cats returned to the T-BASAL top dressed with a dl-Met solution for 4 d prior to being fed a new dietary treatment. Isotopic steady state was evaluated through visual inspection. Data were analyzed using PROC GLIMMIX procedure in SAS 9.4. While 13CO2 enrichment was successfully captured in breath samples, cats failed to reach 13CO2 steady state. Thus, a non-steady state isotope model was developed and coded in ACSLX (V3.1.4.2) individually for each cat on each study day to predict 13CO2 enrichment, and then, calculate oxidation of l-[1-13C]-Phe (F13CO2). A higher predicted F13CO2 was observed for cats fed T-BASAL compared to the others (P < 0.05), while no differences were observed between T-DLM and T-MHA (P > 0.05). Cats fed T-DLM tended to have higher plasma Met concentrations compared to those fed T-BASAL with cats fed T-MHA intermediate (P = 0.0867). Plasma homocysteine concentrations were higher in cats fed T-BASAL compared to the others (P < 0.05), while threonine concentrations tended to be higher in cats fed T-BASAL compared to those fed T-MHA (P = 0.0750). In conclusion, short-term provision of a semi-synthetic diet deficient in Met may elicit a metabolic response aiming to conserve Met. The successful quantification of 13CO2 enrichment in breath and the higher predicted F13CO2 in cats fed a Met deficient diet suggest that the IAAO technique may be used in cats. Adaptations in the isotope protocol should be made to achieve 13CO2 steady state in breath and avoid mathematical modeling to predict F13CO2.
Collapse
Affiliation(s)
- Julia Guazzelli Pezzali
- Center for Nutrition Modelling, Department of Animal Biosciences, University of Guelph, Guelph, Ontario, Canada
| | - Mahroukh Rafii
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Glenda Courtney-Martin
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada
| | - John P Cant
- Center for Nutrition Modelling, Department of Animal Biosciences, University of Guelph, Guelph, Ontario, Canada
| | - Anna K Shoveller
- Center for Nutrition Modelling, Department of Animal Biosciences, University of Guelph, Guelph, Ontario, Canada
| |
Collapse
|
6
|
Wolfe RR, Kim IY, Park S, Ferrando A. Tracing metabolic flux to assess optimal dietary protein and amino acid consumption. EXPERIMENTAL & MOLECULAR MEDICINE 2022; 54:1323-1331. [PMID: 36075948 PMCID: PMC9534933 DOI: 10.1038/s12276-022-00817-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 02/26/2022] [Accepted: 06/15/2022] [Indexed: 12/02/2022]
Abstract
There is a general consensus that a dietary protein intake of 0.8 g protein/kg/day will prevent symptoms of protein deficiency in young, healthy individuals. However, individuals in many physiological circumstances may benefit from higher rates of dietary protein intake. Stable isotope tracer methodology enables a variety of approaches to assessing the optimal dietary protein intake in humans. In this paper, we present an overview of a variety of tracer methods, with a discussion of necessary assumptions, as well as the clinical circumstances in which different methods may be preferable. Although we discuss the nontracer method of nitrogen balance, which has historically been used to estimate dietary protein requirements, this paper primarily focuses on tracer methods for estimating dietary protein and essential amino acid requirements under different physiological conditions. We will explain the following approaches: isotopic measurement of urea production; the arterial-venous tracer balance method; measurement of the fractional synthetic and breakdown rates of muscle protein; the indicator and the direct amino acid oxidation methods; and different approaches to measuring whole-body protein synthesis and breakdown. The advantages and limitations of each method are discussed in the context of the optimal approaches for use under different circumstances. Both clinical and practical considerations should inform how dietary protein intake is tracked in individuals. Little is known about optimal dietary protein intake in humans under different physiological conditions including disease states, prompting a review of current monitoring methods by Robert Wolfe at the University of Arkansas, Little Rock, USA, and co-workers. Monitoring nitrogen balance provides estimates of dietary protein and essential amino acid (EAA) levels, but requires several days of strict diet control. Various techniques monitor the uptake or fate of a specific tracer molecule in the body, but some are very invasive. The less invasive single EAA infusion methods provide rapid results and are valuable for monitoring immediate response to a meal, or in studies comparing protein intakes to a person’s baseline over time. Using two methods concurrently could improve accuracy of results.
Collapse
Affiliation(s)
- Robert R Wolfe
- Department of Geriatrics, Center for Translational Research in Aging & Longevity, Donald W. Reynolds Institute on Aging, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
| | - Il-Young Kim
- Department of Molecular Medicine, College of Medicine, Gachon University, Incheon, Korea.,Korea Mouse Metabolic Phenotyping Center, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon, 21999, Korea
| | - Sanghee Park
- Department of Molecular Medicine, College of Medicine, Gachon University, Incheon, Korea
| | - Arny Ferrando
- Department of Geriatrics, Center for Translational Research in Aging & Longevity, Donald W. Reynolds Institute on Aging, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| |
Collapse
|
7
|
Kuczmarski MF, Beydoun MA, Zonderman AB, Evans MK. Intakes of Total and Branched-Chain Essential Amino Acids are Positively Associated with Handgrip Strength in African American and White Urban Younger and Older Adults. J Nutr Gerontol Geriatr 2022; 41:140-159. [PMID: 35502538 PMCID: PMC9733588 DOI: 10.1080/21551197.2022.2070321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Essential amino acids (EAAs) initiate amino acid-induced stimulation of muscle protein synthesis. Study objectives were to calculate intake of EAAs after creating an EAA database, to explore the association of EAAs and branched-chain amino acids (BCAAs) with handgrip strength (HS) in a younger (<50 y) and older (≥50 y) sample, and to identify major food groups contributing EAAs. The sample consisted of African American and White adults aged, 33-71 years from the Healthy Aging in Neighborhoods of Diversity across the Life Span study, 2009-2013. Intake of total EAAs and BCAAs/kg body weight were positively associated (p < 0.001) with HS per body mass index (HS/BMI) ratio. Being male, African American, a nonsmoker, physically active, euglycemic, and normotensive were associated with higher HS/BMI ratio. EAAs were mainly obtained from red meats/poultry and mixed dishes groups. Findings support the role of high-quality proteins and being active in promoting HS.
Collapse
Affiliation(s)
- Marie Fanelli Kuczmarski
- Laboratory of Epidemiology and Population Sciences, National Institute on Aging, NIH, 251 Bayview Blvd. Suite 100, Baltimore, MD 21224-6825, United States,Corresponding author: Ph: +1-410-995-3639; Fax: +1-410-995-3639,
| | - May A Beydoun
- Laboratory of Epidemiology and Population Sciences, National Institute on Aging, NIH, 251 Bayview Blvd. Suite 100, Baltimore, MD 21224-6825, United States
| | - Alan B. Zonderman
- Laboratory of Epidemiology and Population Sciences, National Institute on Aging, NIH, 251 Bayview Blvd. Suite 100, Baltimore, MD 21224-6825, United States
| | - Michele K. Evans
- Laboratory of Epidemiology and Population Sciences, National Institute on Aging, NIH, 251 Bayview Blvd. Suite 100, Baltimore, MD 21224-6825, United States
| |
Collapse
|
8
|
Szwiega S, Pencharz PB, Rafii M, Lebarron M, Chang J, Ball RO, Kong D, Xu L, Elango R, Courtney-Martin G. Dietary leucine requirement of older men and women is higher than current recommendations. Am J Clin Nutr 2020; 113:410-419. [PMID: 33330915 PMCID: PMC7851820 DOI: 10.1093/ajcn/nqaa323] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 10/12/2020] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Current national (34 mg . kg-1 . d-1) and international (39 mg kg-1 . d-1) recommendations for leucine in older adults are based on data from young adults. Evidence suggests that the leucine requirements of older adults are higher than those of young adults. OBJECTIVE The objective of the current study was to directly determine the leucine requirements in healthy older adult male and female study participants aged >60 y. METHODS Leucine requirement was determined using the indicator amino acid oxidation method (IAAO) with l-[1-13C]phenylalanine as the indicator. Sixteen older adults (n = 7 male and n = 9 female participants) were randomly assigned to receive 3 to 7 leucine intakes from 20 to 120 mg . kg-1 . d-1. The rate of release of 13CO2 from l-[1-13C]phenylalanine oxidation was measured, and breakpoint analysis was used to estimate the leucine requirement. The 95% CI was calculated using the parametric bootstrap method. RESULTS The mean leucine requirement for male participants was 77.8 mg . kg-1 . d-1 (upper 95% CI: 81.0) and for female participants, it was 78.2 mg . kg-1 . d-1 (upper 95% CI: 82.0) with no sex effect based on body weight. The data were therefore combined to yield a mean of 78.5 mg . kg-1 d-1 (upper 95% CI: 81.0 mg . kg-1 . d-1 ) for both sexes. On the basis of fat-free mass, the mean ± SEM leucine requirements were 115 ± 3.2 and 127 ± 2.4 mg . kg-1 . d-1 for male and female participants, respectively (P < 0.005). CONCLUSIONS The estimated leucine requirement of older adults is more than double the amount in current recommendations. These data suggest that leucine could be a limiting amino acid in the diet of older adults consuming the current RDA for protein and those consuming a plant-based diet. In view of the functional and structural role of leucine, especially its importance in muscle protein synthesis, current leucine recommendations of older adults should be revised. This trial was registered at clinicaltrials.gov as NCT03506126.
Collapse
Affiliation(s)
- Sylwia Szwiega
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Paul B Pencharz
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada,Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada,Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Mahroukh Rafii
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Mackenzie Lebarron
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Jessica Chang
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Ronald O Ball
- Department of Agriculture, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Dehan Kong
- Department of Statistical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Libai Xu
- Department of Statistical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Rajavel Elango
- Department of Pediatrics, School of Population and Public Health, University of British Columbia, Vancouver, BC, Canada,BC Children's Hospital Research Institute, BC Children's Hospital, Vancouver, BC, Canada
| | | |
Collapse
|