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P B Pencharz - One of the best experts on this subject based on the ideXlab platform.
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indicator amino acid derived estimate of dietary Protein Requirement for male bodybuilders on a nontraining day is several fold greater than the current recommended dietary allowance
Journal of Nutrition, 2017Co-Authors: Arash Bandegan, P B Pencharz, Mahroukh Rafii, Glenda Courtneymartin, Peter W R LemonAbstract:: Background: Despite a number of studies indicating increased dietary Protein needs in bodybuilders with the use of the nitrogen balance technique, the Institute of Medicine (2005) has concluded, based in part on methodologic concerns, that "no additional dietary Protein is suggested for healthy adults undertaking resistance or endurance exercise."Objective: The aim of the study was to assess the dietary Protein Requirement of healthy young male bodybuilders ( with ≥3 y training experience) on a nontraining day by measuring the oxidation of ingested l-[1-13C]phenylalanine to 13CO2 in response to graded intakes of Protein [indicator amino acid oxidation (IAAO) technique].Methods: Eight men (means ± SDs: age, 22.5 ± 1.7 y; weight, 83.9 ± 11.6 kg; 13.0% ± 6.3% body fat) were studied at rest on a nontraining day, on several occasions (4-8 times) each with Protein intakes ranging from 0.1 to 3.5 g · kg-1 · d-1, for a total of 42 experiments. The diets provided energy at 1.5 times each individual's measured resting energy expenditure and were isoenergetic across all treatments. Protein was fed as an amino acid mixture based on the Protein pattern in egg, except for phenylalanine and tyrosine, which were maintained at constant amounts across all Protein intakes. For 2 d before the study, all participants consumed 1.5 g Protein · kg-1 · d-1 On the study day, the Protein Requirement was determined by identifying the breakpoint in the F13CO2 with graded amounts of dietary Protein [mixed-effects change-point regression analysis of F13CO2 (labeled tracer oxidation in breath)].Results: The Estimated Average Requirement (EAR) of Protein and the upper 95% CI RDA for these young male bodybuilders were 1.7 and 2.2 g · kg-1 · d-1, respectively.Conclusion: These IAAO data suggest that the Protein EAR and recommended intake for male bodybuilders at rest on a nontraining day exceed the current recommendations of the Institute of Medicine by ∼2.6-fold. This trial was registered at clinicaltrials.gov as NCT02621294.
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dietary Protein Requirement of men 65 years old determined by the indicator amino acid oxidation technique is higher than the current estimated average Requirement
Journal of Nutrition, 2015Co-Authors: Mahroukh Rafii, Wayne W. Campbell, Rajavel Elango, P B Pencharz, Ronald O Ball, Karen P Chapman, Glenda CourtneymartinAbstract:Background The current estimated average Requirement (EAR) and RDA for Protein of 0.66 and 0.8 g ⋅ kg-1 ⋅ d-1, respectively, for adults, including older men, are based on nitrogen balance data analyzed by monolinear regression. Recent studies in young men and older women that used the indicator amino acid oxidation (IAAO) technique suggest that those values may be too low. This observation is supported by 2-phase linear crossover analysis of the nitrogen balance data. Objective The main objective of this study was to determine the Protein Requirement for older men by using the IAAO technique. Methods Six men aged >65 y were studied; each individual was tested 7 times with Protein intakes ranging from 0.2 to 2.0 g ⋅ kg-1 ⋅ d-1 in random order for a total of 42 studies. The diets provided energy at 1.5 times the resting energy expenditure and were isocaloric. Protein was consumed hourly for 8 h as an amino acid mixture with the composition of egg Protein with L-[1-13C]phenylalanine as the indicator amino acid. The group mean Protein Requirement was determined by applying a mixed-effects change-point regression analysis to F13CO2 (label tracer oxidation in breath 13CO2), which identified a breakpoint in F13CO2 in response to graded intakes of Protein. Results The estimated Protein Requirement and RDA for older men were 0.94 and 1.24 g ⋅ kg-1 ⋅ d-1, respectively, which are not different from values we published using the same method in young men and older women. Conclusions The current intake recommendations for older adults for dietary Protein of 0.66 g ⋅ kg-1 ⋅ d-1 for the EAR and 0.8 g ⋅ kg-1 ⋅ d-1 for the RDA appear to be underestimated by ∼30%. Future longer-term studies should be conducted to validate these results. This trial was registered at clinicaltrials.gov as NCT01948492.
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dietary Protein Requirement of female adults 65 years determined by the indicator amino acid oxidation technique is higher than current recommendations
Journal of Nutrition, 2015Co-Authors: Mahroukh Rafii, Wayne W. Campbell, Rajavel Elango, P B Pencharz, Ronald O Ball, Karen P Chapman, Jillian Owens, Glenda CourtneymartinAbstract: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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assessment of Protein Requirement in octogenarian women with use of the indicator amino acid oxidation technique
The American Journal of Clinical Nutrition, 2014Co-Authors: Minghua Tang, George P. Mccabe, Rajavel Elango, P B Pencharz, Ronald O Ball, Wayne W. CampbellAbstract:Background: Data on the Protein Requirements of elderly adults are limited, because it is impractical to conduct repeated nitrogen balance protocols in these vulnerable humans. Objective: This study was designed to determine the dietary Protein Requirement of elderly women by using the recently developed minimally invasive indicator amino acid oxidation (IAAO) technique. Design: Six white women aged 80–87 y [mean ± SEM: 82 ± 1 y and body mass index (in kg/m2) 26 ± 2] completed a 3-d protocol 7 times. Each woman consumed an adaptation diet for 2 d and on day 3 consumed a complete test diet with a crystalline amino acid mixture containing 1 of 7 Protein intakes (0.1, 0.3, 0.6, 0.9, 1.2, 1.5, or 1.8 g · kg−1 · d−1) tested randomly. A group-based Protein Requirement was assessed by using a nonlinear mixed model of Protein intake and l-[1-13C]phenylalanine oxidation. The breakpoint, at which there was no further decline in the rate of appearance of 13C in the breath, was used as an index of the mean Protein Requirement. Results: The mean Protein Requirement (95% CI) was 0.85 (0.60, 1.09) g · kg−1 · d−1. This Requirement is 29% higher than the current Estimated Average Requirement (EAR) for adults of 0.66 g · kg−1 · d−1 based on the nitrogen balance technique, although the 95% CI includes the current EAR. The corresponding adequate Protein allowance of 1.15 (0.77, 1.54) g · kg−1 · d−1 is 44% higher, although the 95% CI includes the Recommended Dietary Allowance (RDA) of 0.80 g · kg−1 · d−1. Conclusions: Notwithstanding uncertainty about the validity of the use of the IAAO technique to assess Protein Requirements, the results of this study with octogenarian women suggest that the current EAR and RDA for elderly women may be underestimated. The limitations of this short-term, noninvasive method underscore the need for new research that uses alternative experimental designs and measuring physiologic, morphologic, and health-related outcomes. This trial was registered at clinicaltrials.gov as NCT01193946.
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Protein Requirement of healthy school age children determined by the indicator amino acid oxidation method
The American Journal of Clinical Nutrition, 2011Co-Authors: Rajavel Elango, Ronald O Ball, Mohammad A Humayun, P B PencharzAbstract:BACKGROUND The current Dietary Reference Intake (DRI) recommendations for Protein Requirements in children are based on a factorial estimate and have not been directly determined. OBJECTIVE The objective of the current study was to determine the Protein Requirement in healthy, school-age children by measuring the oxidation of L-[1-(13)C]-phenylalanine to (13)CO(2) [label tracer oxidation (F(13)CO(2))] in response to graded intakes of Protein. DESIGN Seven healthy children (6-11 y old) each randomly received a minimum of 7 Protein intakes (range: 0.1-2.56 g · kg(-1) · d(-1)) for a total of 56 studies. The diets provided energy at 1.7 times the resting energy expenditure and were made isocaloric by using carbohydrate. Protein was given as an amino acid mixture on the basis of the egg-Protein pattern, except for phenylalanine and tyrosine intakes, which were maintained constant across intakes. The mean Protein Requirement was determined by applying a 2-phase linear regression crossover analysis on F(13)CO(2) data, which identified a breakpoint (Requirement) at minimal F(13)CO(2) in response to graded amounts of Protein intake. RESULTS Mean and population-safe (upper 95% CI) Protein Requirements were determined to be 1.3 and 1.55 g · kg(-1) · d(-1), respectively. These results are significantly higher than the mean and population-safe Protein Requirements currently recommended by the DRI 2005 for macronutrients (0.76 and 0.95 g · kg(-1) · d(-1), respectively). CONCLUSION To our knowledge, this study was the first to directly estimate Protein Requirements in children by using stable isotopes and indicated that current recommendations are severely underestimated.
Kyeongjun Lee - One of the best experts on this subject based on the ideXlab platform.
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Dietary Protein Requirement of Pacific white shrimp Litopenaeus vannamei in three different growth stages
Fisheries and Aquatic Sciences, 2018Co-Authors: Chorong Lee, Kyeongjun LeeAbstract:A study of three feeding trials was conducted to investigate the dietary Protein Requirements of Pacific white shrimp ( Litopenaeus vannamei ) at three different growth stages. Six experimental diets were formulated to include increasing Protein levels of 25, 30, 35, 40, 45, and 50% (designated as P25, P30, P35, P40, P45, and P50, respectively) for three feeding trials. The three feeding trials were conducted in different-sized shrimp at 0.65 g (trial 1), 4.80 g (trial 2), and 10.5 g (trial 3). Triplicate groups of shrimp were fed one of the experimental diets for 36, 42, and 48 days in trials 1, 2, and 3, respectively. In trial 1, the growth performance was not affected by the dietary Protein levels. However, Protein efficiency ratio was significantly higher in P30 diet compared to P40, P45, and P50 diets. In trial 2, growth rate was significantly higher in P35 diet than in P25 diet. In trial 3, the lowest growth performance was obtained in P25 diet which significantly differed from that of other experimental diets. Broken line analysis of growth data indicates that the optimal dietary level of crude Protein is 34.5, 35.6, and 32.2% for small-, medium-, and large-sized (juvenile, sub-adult, and adult stages) Pacific white shrimp, respectively.
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dietary Protein Requirement of juvenile tiger puffer takifugu rubripes
Aquaculture, 2009Co-Authors: Sungsam Kim, Kyeongjun LeeAbstract:Abstract This study was conducted to determine the optimum dietary Protein Requirement for the growth of juvenile (initial weight, 17.05 ± 0.17 g) tiger puffer. Five semi-purified diets were formulated with casein to contain graded levels of Protein levels of 35, 40, 45, 50 and 55%. Each diet was fed to triplicate groups of the fish in a flow-through system for 8 weeks. After the 8-week feeding trial, growth of fish fed the 40% diet was not significantly different from that of fish fed 45, 50 or 55% dietary Protein, but significantly higher than that of fish fed the 35% diet. The lowest feed efficiency was found in fish groups fed 35% diet. Protein efficiency ratio of fish fed the 45, 50 and 55% diets was significantly lower than that of fish fed the 35 and 40% diets. No significant differences were observed in feed intake and survival among all the fish groups. Serum aspartate aminotransferase activity of fish fed the 45% diet was significantly lower than that of fish fed the 35% diet, but was not significantly different from that of fish fed the 40, 50 and 55% diets. Whole body Protein content of fish fed the 50 and 55% diets was significantly higher than that of fish fed the 35% diet, but was not significantly different from that of fish fed the 40 and 45% diets. This result indicates that juvenile tiger puffer requires approximately 41% dietary Protein for optimum growth and physiological performances.
Wayne W. Campbell - One of the best experts on this subject based on the ideXlab platform.
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dietary Protein Requirement of men 65 years old determined by the indicator amino acid oxidation technique is higher than the current estimated average Requirement
Journal of Nutrition, 2015Co-Authors: Mahroukh Rafii, Wayne W. Campbell, Rajavel Elango, P B Pencharz, Ronald O Ball, Karen P Chapman, Glenda CourtneymartinAbstract:Background The current estimated average Requirement (EAR) and RDA for Protein of 0.66 and 0.8 g ⋅ kg-1 ⋅ d-1, respectively, for adults, including older men, are based on nitrogen balance data analyzed by monolinear regression. Recent studies in young men and older women that used the indicator amino acid oxidation (IAAO) technique suggest that those values may be too low. This observation is supported by 2-phase linear crossover analysis of the nitrogen balance data. Objective The main objective of this study was to determine the Protein Requirement for older men by using the IAAO technique. Methods Six men aged >65 y were studied; each individual was tested 7 times with Protein intakes ranging from 0.2 to 2.0 g ⋅ kg-1 ⋅ d-1 in random order for a total of 42 studies. The diets provided energy at 1.5 times the resting energy expenditure and were isocaloric. Protein was consumed hourly for 8 h as an amino acid mixture with the composition of egg Protein with L-[1-13C]phenylalanine as the indicator amino acid. The group mean Protein Requirement was determined by applying a mixed-effects change-point regression analysis to F13CO2 (label tracer oxidation in breath 13CO2), which identified a breakpoint in F13CO2 in response to graded intakes of Protein. Results The estimated Protein Requirement and RDA for older men were 0.94 and 1.24 g ⋅ kg-1 ⋅ d-1, respectively, which are not different from values we published using the same method in young men and older women. Conclusions The current intake recommendations for older adults for dietary Protein of 0.66 g ⋅ kg-1 ⋅ d-1 for the EAR and 0.8 g ⋅ kg-1 ⋅ d-1 for the RDA appear to be underestimated by ∼30%. Future longer-term studies should be conducted to validate these results. This trial was registered at clinicaltrials.gov as NCT01948492.
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dietary Protein Requirement of female adults 65 years determined by the indicator amino acid oxidation technique is higher than current recommendations
Journal of Nutrition, 2015Co-Authors: Mahroukh Rafii, Wayne W. Campbell, Rajavel Elango, P B Pencharz, Ronald O Ball, Karen P Chapman, Jillian Owens, Glenda CourtneymartinAbstract: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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Normality of adult dietary Protein Requirement distribution (820.11)
The FASEB Journal, 2014Co-Authors: Richard Ross, George P. Mccabe, Wayne W. Campbell, Craig A. JohnsonAbstract:Nitrogen balance data consistently suggest that the dietary Protein Requirement of adult humans follows a lognormal distribution. In contrast, statistical theory and the associated physiology imply...
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assessment of Protein Requirement in octogenarian women with use of the indicator amino acid oxidation technique
The American Journal of Clinical Nutrition, 2014Co-Authors: Minghua Tang, George P. Mccabe, Rajavel Elango, P B Pencharz, Ronald O Ball, Wayne W. CampbellAbstract:Background: Data on the Protein Requirements of elderly adults are limited, because it is impractical to conduct repeated nitrogen balance protocols in these vulnerable humans. Objective: This study was designed to determine the dietary Protein Requirement of elderly women by using the recently developed minimally invasive indicator amino acid oxidation (IAAO) technique. Design: Six white women aged 80–87 y [mean ± SEM: 82 ± 1 y and body mass index (in kg/m2) 26 ± 2] completed a 3-d protocol 7 times. Each woman consumed an adaptation diet for 2 d and on day 3 consumed a complete test diet with a crystalline amino acid mixture containing 1 of 7 Protein intakes (0.1, 0.3, 0.6, 0.9, 1.2, 1.5, or 1.8 g · kg−1 · d−1) tested randomly. A group-based Protein Requirement was assessed by using a nonlinear mixed model of Protein intake and l-[1-13C]phenylalanine oxidation. The breakpoint, at which there was no further decline in the rate of appearance of 13C in the breath, was used as an index of the mean Protein Requirement. Results: The mean Protein Requirement (95% CI) was 0.85 (0.60, 1.09) g · kg−1 · d−1. This Requirement is 29% higher than the current Estimated Average Requirement (EAR) for adults of 0.66 g · kg−1 · d−1 based on the nitrogen balance technique, although the 95% CI includes the current EAR. The corresponding adequate Protein allowance of 1.15 (0.77, 1.54) g · kg−1 · d−1 is 44% higher, although the 95% CI includes the Recommended Dietary Allowance (RDA) of 0.80 g · kg−1 · d−1. Conclusions: Notwithstanding uncertainty about the validity of the use of the IAAO technique to assess Protein Requirements, the results of this study with octogenarian women suggest that the current EAR and RDA for elderly women may be underestimated. The limitations of this short-term, noninvasive method underscore the need for new research that uses alternative experimental designs and measuring physiologic, morphologic, and health-related outcomes. This trial was registered at clinicaltrials.gov as NCT01193946.
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Increased Protein Requirements in elderly people: new data and retrospective reassessments.
The American journal of clinical nutrition, 1994Co-Authors: Wayne W. Campbell, M C Crim, G. E. Dallal, Vernon R. Young, William J. EvansAbstract:Dietary Protein Requirements of elderly people were determined by short-term nitrogen-balance techniques and using calculations recommended by the 1985 Joint FAO/WHO/UNU Expert Consultation. Twelve men and women aged 56-80 y were randomly assigned to groups that consumed either 0.80 +/- 0.01 or 1.62 +/- 0.02 g Protein.kg-1.d-1 (mean +/- SEM). Net nitrogen balance was negative for the lower-Protein group (-4.6 +/- 3.4 mg N.kg-1.d-1) and positive for the higher-Protein group (13.6 +/- 1.0 mg N.kg-1.d-1); the intake required for nitrogen equilibrium was estimated to be 1.00 g.kg-1.d-1. Nitrogen-balance data from three previous Protein Requirement studies in elderly people were recalculated by using the same balance formula and combined with the current study data to provide an overall weighted mean Protein Requirement estimate of 0.91 +/- 0.043 g.kg-1.d-1. Together, the current and retrospective nitrogen-balance data suggest that the mean Protein Requirement in elderly adults is considerably greater than the 0.60 g.kg-1.d-1 established by the 1985 Joint FAO/WHO/UNU Expert Consultation. A safe Protein intake for elderly adults would be 1.0-1.25 g.kg-1.d-1 of high-quality Protein.
Allen D Davis - One of the best experts on this subject based on the ideXlab platform.
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Protein Requirement for maintenance and maximum weight gain for the pacific white shrimp litopenaeus vannamei
Aquaculture, 2002Co-Authors: Nasir Kureshy, Allen D DavisAbstract:The dietary crude Protein Requirement of penaeid shrimp is an important nutritional consideration because Protein is often the major limiting nutrient for growth. In most cases, research has focused on total dietary Protein levels rather than a daily Requirement for Protein. This research utilized three practical diets containing 16%, 32%, and 48% Protein and various daily rations to estimate daily Requirements for Protein. In the first series of studies, four 28-day feeding trials were conducted to determine the maintenance Requirement for Protein (Protein required to maintain body functions with all other nutrients provided in adequate amounts) by juvenile and subadult shrimp. Shrimp were offered practical diets containing 16% or 32% crude Protein. In order to estimate the maintenance Requirement, weight gain was regressed against daily Protein ration. Juvenile shrimp were found to have maintenance Protein Requirements in the range of 1.8-3.8 g dietary Protein/kg body weight per day (g DP/(kg BWd)), and subadult shrimp were found to have maintenance Protein Requirements in the range of 1.5-2.1 g DP/(kg BWd). Four additional 28-day feeding trials were conducted to determine the Protein Requirement for maximum growth by juvenile and subadult shrimp. These studies, utilized three practical diets containing 16%, 32%, and 48% dietary Protein. On an isonitrogenous basis, the 16% Protein diet produced significantly lower weight gain, feed efficiency (FE), and Protein conversion efficiency values, than the 32% Protein diet for both the juvenile and subadult shrimp. The 48% Protein diet produced significantly lower weight gain in the juvenile shrimp, but there was no significant effect in the subadult shrimp. Feed efficiency values were higher for shrimp fed the 48% Protein diet as compared to those offered the 32% Protein diet. Broken line analysis was conducted on the growth responses for each diet and each size of shrimp, in order to determine the Protein Requirement for maximum growth. Protein Requirement for maximum growth of juvenile shrimp was found to be 46.4 g DP/(kg BWd) when fed the 32% Protein diet and 43.4 g DP/(kg BWd) when fed the 48% Protein diet. Subadult shrimp exhibited a maximum Protein Requirement of 23.5 g DP/(kg BWd) when fed a 32% Protein diet and 20.5 g DP/(kg BWd) when fed a 48% Protein diet. In summary, FE increased as the Protein concentration of the diet increased, and decreased as feeding rates (offered feed/day) increased. Weight gain reflected daily Protein intake. Based on these results, a wide range of dietary Protein levels could be used to produce maximum weight gain of juvenile and subadult shrimp. Due to a restriction of feed intake and consequently Protein intake, low Protein diets did not support maximum weight gain.
Ronald O Ball - One of the best experts on this subject based on the ideXlab platform.
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dietary Protein Requirement of men 65 years old determined by the indicator amino acid oxidation technique is higher than the current estimated average Requirement
Journal of Nutrition, 2015Co-Authors: Mahroukh Rafii, Wayne W. Campbell, Rajavel Elango, P B Pencharz, Ronald O Ball, Karen P Chapman, Glenda CourtneymartinAbstract:Background The current estimated average Requirement (EAR) and RDA for Protein of 0.66 and 0.8 g ⋅ kg-1 ⋅ d-1, respectively, for adults, including older men, are based on nitrogen balance data analyzed by monolinear regression. Recent studies in young men and older women that used the indicator amino acid oxidation (IAAO) technique suggest that those values may be too low. This observation is supported by 2-phase linear crossover analysis of the nitrogen balance data. Objective The main objective of this study was to determine the Protein Requirement for older men by using the IAAO technique. Methods Six men aged >65 y were studied; each individual was tested 7 times with Protein intakes ranging from 0.2 to 2.0 g ⋅ kg-1 ⋅ d-1 in random order for a total of 42 studies. The diets provided energy at 1.5 times the resting energy expenditure and were isocaloric. Protein was consumed hourly for 8 h as an amino acid mixture with the composition of egg Protein with L-[1-13C]phenylalanine as the indicator amino acid. The group mean Protein Requirement was determined by applying a mixed-effects change-point regression analysis to F13CO2 (label tracer oxidation in breath 13CO2), which identified a breakpoint in F13CO2 in response to graded intakes of Protein. Results The estimated Protein Requirement and RDA for older men were 0.94 and 1.24 g ⋅ kg-1 ⋅ d-1, respectively, which are not different from values we published using the same method in young men and older women. Conclusions The current intake recommendations for older adults for dietary Protein of 0.66 g ⋅ kg-1 ⋅ d-1 for the EAR and 0.8 g ⋅ kg-1 ⋅ d-1 for the RDA appear to be underestimated by ∼30%. Future longer-term studies should be conducted to validate these results. This trial was registered at clinicaltrials.gov as NCT01948492.
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dietary Protein Requirement of female adults 65 years determined by the indicator amino acid oxidation technique is higher than current recommendations
Journal of Nutrition, 2015Co-Authors: Mahroukh Rafii, Wayne W. Campbell, Rajavel Elango, P B Pencharz, Ronald O Ball, Karen P Chapman, Jillian Owens, Glenda CourtneymartinAbstract: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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assessment of Protein Requirement in octogenarian women with use of the indicator amino acid oxidation technique
The American Journal of Clinical Nutrition, 2014Co-Authors: Minghua Tang, George P. Mccabe, Rajavel Elango, P B Pencharz, Ronald O Ball, Wayne W. CampbellAbstract:Background: Data on the Protein Requirements of elderly adults are limited, because it is impractical to conduct repeated nitrogen balance protocols in these vulnerable humans. Objective: This study was designed to determine the dietary Protein Requirement of elderly women by using the recently developed minimally invasive indicator amino acid oxidation (IAAO) technique. Design: Six white women aged 80–87 y [mean ± SEM: 82 ± 1 y and body mass index (in kg/m2) 26 ± 2] completed a 3-d protocol 7 times. Each woman consumed an adaptation diet for 2 d and on day 3 consumed a complete test diet with a crystalline amino acid mixture containing 1 of 7 Protein intakes (0.1, 0.3, 0.6, 0.9, 1.2, 1.5, or 1.8 g · kg−1 · d−1) tested randomly. A group-based Protein Requirement was assessed by using a nonlinear mixed model of Protein intake and l-[1-13C]phenylalanine oxidation. The breakpoint, at which there was no further decline in the rate of appearance of 13C in the breath, was used as an index of the mean Protein Requirement. Results: The mean Protein Requirement (95% CI) was 0.85 (0.60, 1.09) g · kg−1 · d−1. This Requirement is 29% higher than the current Estimated Average Requirement (EAR) for adults of 0.66 g · kg−1 · d−1 based on the nitrogen balance technique, although the 95% CI includes the current EAR. The corresponding adequate Protein allowance of 1.15 (0.77, 1.54) g · kg−1 · d−1 is 44% higher, although the 95% CI includes the Recommended Dietary Allowance (RDA) of 0.80 g · kg−1 · d−1. Conclusions: Notwithstanding uncertainty about the validity of the use of the IAAO technique to assess Protein Requirements, the results of this study with octogenarian women suggest that the current EAR and RDA for elderly women may be underestimated. The limitations of this short-term, noninvasive method underscore the need for new research that uses alternative experimental designs and measuring physiologic, morphologic, and health-related outcomes. This trial was registered at clinicaltrials.gov as NCT01193946.
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Protein Requirement of healthy school age children determined by the indicator amino acid oxidation method
The American Journal of Clinical Nutrition, 2011Co-Authors: Rajavel Elango, Ronald O Ball, Mohammad A Humayun, P B PencharzAbstract:BACKGROUND The current Dietary Reference Intake (DRI) recommendations for Protein Requirements in children are based on a factorial estimate and have not been directly determined. OBJECTIVE The objective of the current study was to determine the Protein Requirement in healthy, school-age children by measuring the oxidation of L-[1-(13)C]-phenylalanine to (13)CO(2) [label tracer oxidation (F(13)CO(2))] in response to graded intakes of Protein. DESIGN Seven healthy children (6-11 y old) each randomly received a minimum of 7 Protein intakes (range: 0.1-2.56 g · kg(-1) · d(-1)) for a total of 56 studies. The diets provided energy at 1.7 times the resting energy expenditure and were made isocaloric by using carbohydrate. Protein was given as an amino acid mixture on the basis of the egg-Protein pattern, except for phenylalanine and tyrosine intakes, which were maintained constant across intakes. The mean Protein Requirement was determined by applying a 2-phase linear regression crossover analysis on F(13)CO(2) data, which identified a breakpoint (Requirement) at minimal F(13)CO(2) in response to graded amounts of Protein intake. RESULTS Mean and population-safe (upper 95% CI) Protein Requirements were determined to be 1.3 and 1.55 g · kg(-1) · d(-1), respectively. These results are significantly higher than the mean and population-safe Protein Requirements currently recommended by the DRI 2005 for macronutrients (0.76 and 0.95 g · kg(-1) · d(-1), respectively). CONCLUSION To our knowledge, this study was the first to directly estimate Protein Requirements in children by using stable isotopes and indicated that current recommendations are severely underestimated.
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reevaluation of the Protein Requirement in young men with the indicator amino acid oxidation technique
The American Journal of Clinical Nutrition, 2007Co-Authors: Mohammad A Humayun, Rajavel Elango, Ronald O Ball, P B PencharzAbstract:Background: The current estimated Protein Requirements are based on the nitrogen balance method, which has many limitations. An alternate approach is needed to permit a reevaluation of Protein Requirements. Objective: The objective was to determine Protein Requirements in men by using the indicator amino acid oxidation technique. Design: Eight healthy men randomly received graded Protein intakes (0.10, 0.30, 0.60, 0.90, 1.2, 1.5 and 1.8 g·kg -1 ·d -1 ) as a crystalline amino acid mixture along with L-[1- 13 C]phenylalanine. The mean Protein Requirement was determined by applying a biphase linear regression crossover analysis on F 13 CO 2 data, which identified a breakpoint at the minimal rate of appearance of 13 CO 2 to graded Protein intakes. Results: The mean and population-safe (recommended dietary allowance; RDA) Protein Requirements were found to be 0.93 and 1.2 g · kg -1 ·d -1 , respectively. These Requirements are comparable with those estimated by the application of a biphase linear regression model to the data from nitrogen balance studies (0.91 and 1.0 g ·kg -1 ·d -1 , respectively). These Requirements are 41% and 50% higher than the current recommendations for the estimated average Requirement (EAR) of 0.66 g ·kg -1 ·d -1 and the RDA of 0.80 g ·kg -1 · d -1 , as determined by applying a linear regression model where it intersects the zero balance line. Conclusion: The indicator amino acid oxidation technique defined a Protein Requirement that is comparable with that estimated by the application of a biphase linear regression model to nitrogen balance data in the literature. Our data and the reanalysis of the preexisting nitrogen balance data suggest that the current recommended Protein Requirements are too low and require reassessment.
