Protein Requirements Of Adults Research Articles

61 Life Stage Feeding: Is There Path Forward for Senior/Geriatric Nutrient recommendations?

Abstract Complete and balanced foods for “all life stages”, according to the Association of American Feed Control Officials (AAFCO), meet the needs for reproduction and growth. While these are recognized as the most nutritionally demanding stages, they are relatively short time periods in the life of a pet. Unique to companion animals, and humans, is the prolonged “senior” life stage. Although this stage is not well defined, it has become evident that energy, protein and other nutrient requirements may change with age in seniors. To establish guidelines for a lifestage, that lifestage must be defined (Table 1). Species and breed differences exist in terms of aging, in that small breed dogs have longer lifespans versus large breed dogs, and cats differ from dogs, with cats showing a definable fourth lifestage of “geriatric” that differs from a “senior” lifestage. A major challenge to defining senior or geriatric nutritional needs is the fact that animals “age” at different rates, causing senior/geriatric to be the most physiologically diverse lifestage. In nutritionally complete and balanced foods, nutrients are provided in proportion to the energy content of the diet and to the expected energy intake of the pet. Regardless of lifestage, energy requirements can differ significantly among dog breeds and among individuals. Added to this is evidence that energy requirements in dogs decrease with age, such that senior dogs need about 25% fewer calories, on average, than young adult dogs. Likewise, senior cats show a decrease in energy requirements, but geriatric cats display an increase in energy needs. Thus, even if the absolute requirement for nutrients did not change with age, the content needed on an energy basis will change. One of the challenges to establishing protein requirements for senior and geriatric pets is age-related loss of lean body mass (LBM), or sarcopenia. LBM serves as a protein reservoir and provides the amino acids used on a 24/7 basis for endogenous protein synthesis, while dietary protein maintains or restores this reservoir. It has become evident that nitrogen balance studies, long used to determine protein requirements for adults, are not sufficient in that they do not account for contributions from LBM. Maintenance of LBM may be a better assay for defining protein requirements. However, LBM is lost with age in all species studied, including humans, dogs and cats. Geriatric cats lose approximately one third of their LBM, while senior dogs lose about 10%. Loss of LBM is associated with greater morbidity and mortality, thus, preservation of LBM is an important goal. While increasing protein intake can slow the loss, and vice versa, increasing protein intake alone cannot prevent loss of LBM. Therefore, an important challenge is to determine how to measure protein requirements in aging pets.

Protein Quality Assessment of Follow-up Formula for Young Children and Ready-to-Use Therapeutic Foods: Recommendations by the FAO Expert Working Group in 2017

The FAO of the UN convened an Expert Working Group meeting to provide recommendations related to protein quality evaluation of Follow-up Formula for Young Children (FUF-YC) and Ready-to-Use Therapeutic Foods (RUTFs). The protein and amino acid (AA) scoring patterns for the target age groups were defined and recommendations provided on the use of currently available protein and indispensable AA digestibility data. For FUF-YC, an age category of 1-2.9 y was identified, and a matching protein requirement of 0.86g · kg-1 · d-1 with corresponding AA requirements were recommended. For RUTF, the protein requirement recommended was 2.82g · kg-1 · d-1, to achieve a catch-up weight gain of 10g · kg-1 · d-1 in children recovering from severe acute malnutrition. The AA requirements were factorially derived based on the adult protein requirement for maintenance and tissue AA composition. A flowchart was proposed for the best available methods to estimate digestibility coefficients (of either protein or AAs), in the following order: human, growing pig, and rat true ileal AA digestibility values. Where this is not possible, fecal protein digestibility values should be used. The Expert Working Group recommends the use of the Protein Digestibility Corrected Amino Acid Score (PDCAAS), with existing protein digestibility values, or the Digestible Indispensable Amino Acid Score provided that individual AA digestibility values are available for protein quality evaluation using the latter score. The Group also recommends the use of ileal digestibility of protein or of AAs for plant-based protein sources, recognizing the possible effects of antinutritional factors and impaired gut function. A PDCAAS score of ≥90% can be considered adequate for these formulations, whereas with a score <90%, the quantity of protein should be increased to meet the requirements. Regardless of the protein quality score, the ability of formulations to support growth in the target population should be evaluated. Future research recommendations are also proposed based on the knowledge gaps identified.

Profile and nutritional value of fatty acids in selected skeletal muscles of Polish Holstein-Friesian bu

The aim of the study was to compare the skeletal muscles (longissimus lumborum – LL vs. semitendinosus – ST) of Polish Holstein-Friesian bulls in terms of their chemical composition, fatty acid proportions and the degree to which they meet standards for selected nutrients. The proximate composition, that is, the content of water, ash, crude protein, fat and collagen, was determined in the muscle samples collected. The calorific value of 100 g of meat was calculated based on the total protein content and intramuscular fat, using energy equivalents: 4 kcal for protein and 9 kcal for fat. The fatty acid profile (FA) was determined by gas chromatography (GC-FID), and the following groups were distinguished: saturated fatty acids (SFA), monounsaturated fatty acids in the cis (MUFA cis) and the trans configuration (MUFA trans), as well as polyunsaturated fatty acids (PUFA). On the basis of the content of individual fatty acids, the ratio of PUFA/SFA and n-6/n-3 was calculated. In addition, the following indices were calculated: atherogenic index (AI), thrombogenic index (TI), saturation index (S/P), as well as nutritional value (NV) and the ratio of hypo- and hypercholesterolaemic fatty acids (h/H). The results obtained for fatty acids were expressed as 1) percentage of individual fatty acids in total FAs quantified and 2) as quantity (in mg) per 100 g of fresh meat. Statistical calculations were performed using Statistica software ver. 13. Differences between the muscles were verified with the t-test for independent samples, assuming significance levels of p ≤ 0.05 and p ≤ 0.01. The muscle type was found to significantly influence the fatty acid (FA) profile for four of the 24 FAs identified. Compared to ST, the LL muscle had a significantly higher share of C18:0 (18.95% vs. 16.55%; p ≤ 0.01) and CLA (0.38% vs. 0.29%; p ≤ 0.05) and significantly lower percentages of C16:1 c9 (3.17% vs. 3.74%; p ≤ 0.05) and C18:1 c9 (36.02% vs. 38.65%; p ≤ 0.05). With regard to particular groups of fatty acids, the LL muscle had significantly higher percentages of SFA (53.20% vs. 50.71%, p ≤ 0.05), PUFA (4.20% vs. 3.49%, p ≤ 0.05) and n-6 (2.69% vs. 2.10%, p ≤ 0.01) and a significantly lower percentage of cis MUFA (40.73% vs. 43.96%; p ≤ 0.01). The average amount of fat in 100 g of muscle tissue was 693.30 mg for SFA, 560.81 mg for MUFA cis, 54.74 mg for PUFA (including 33.87 mg of n-6 and 16.23 mg of n-3) and 24.63 mg for MUFA trans. The beef can be classified as a secondary source of fatty acids. The coverage of the recommended intake ranged from 2.5% to 3.8% for SFA, from 1.1% to 1.9% for MUFA, from 0.29% to 1.8% for n-3 acids, and was smaller than 1% for PUFA and n-6. The amount of EPA and DHA satisfied from 0.66% to 1.3% of the minimum daily requirement, while the amount of trans FA ranged from 0.9% to 1.4% of the maximum daily level. It is worth noting that 100 g of the beef provided on average 102.53 kcal, 1.46 g of fat and 22.34 g of protein, which cover, respectively, 5.1% of the daily calorie requirement, 1.9-3.3% of the fat requirement, and as much as 30-45% of the protein requirement for adults. Although the ST muscle, because of its 40% lower fat content and 2% lower protein content, was less caloric than the LL muscle, it also contained fewer biologically active FAs, including CLA, VA, ALA, LA, AA, EPA and DPA. Irrespective of the differences shown, the meat can be classified as a low-calorie and high-protein product, as 87% of its energy value came from protein.

Will We Ever Agree on Protein Requirements in the Intensive Care Unit?

The precise value of the normal adult protein requirement has long been debated. For many reasons-one of them being the difficulty of carrying out long-term nutrition experiments in free-living people-uncertainty is likely to persist indefinitely. By contrast, the controlled environment of the intensive care unit and relatively short trajectory of many critical illnesses make it feasible to use hard clinical outcome trials to determine protein requirements for critically ill patients in well-defined clinical situations. This article suggests how the physiological principles that underlie our understanding of normal protein requirements can be incorporated into the design of such clinical trials. The main focus is on 3 principles: (1) the rate of body nitrogen loss roughly predicts an individual's minimum protein requirement and is thus essential to measure to identify individual patients and clinical situations in which the minimum protein requirement is importantly increased, (2) existing muscle mass sets an upper limit on the rate at which amino acids can be mobilized from muscle for transfer to central proteins and sites of injury and is thus important to monitor to identify patients who are at greatest risk of protein deficiency-related adverse outcomes, and (3) negative energy balance increases the dietary protein requirement, so calorie-deprived patients-whether obese or not-should be enrolled in hard clinical outcome trials that compare the current practice of "permissive underfeeding" (underprovision of all nutrients, including protein) with hypocaloric nutrition supplemented by a suitably generous amount of protein.

Protein requirements and aging 1

Protein requirements and aging 1

British Dietetic Association evidence‐based guidelines for the protein requirements of adults undergoing maintenance haemodialysis or peritoneal dialysis

Existing nutritional guidelines suggest that protein requirements of adults with stage five chronic kidney disease undergoing haemodialysis (HD) or peritoneal dialysis (PD) are increased as a result of protein losses during dialysis. The present review aimed to update previous guidance and develop evidence-based practice guidelines on the protein requirements of adults undergoing maintenance dialysis. Following a PICO approach (Participants or Population, Intervention or Exposure, Comparison and Outcome), four research questions were formulated to investigate the total protein requirement and protein quality required by adults undergoing HD and PD. A comprehensive, systematic review was undertaken using the databases Medline, EMBASE and the Cochrane Library from 2005 to September 2009 for HD studies and from 1997 to September 2009 for PD studies. The literature search yielded 2931 studies, which were assessed for inclusion. Following appraisal, 19 studies in HD and 18 studies in PD met the inclusion criteria and were systematically reviewed. Limited good quality evidence supports the recommendations that: (i) adults undergoing maintenance HD require a minimum protein intake of 1.1gkg(-1) ideal body weight (IBW) per day; and (ii) adults undergoing maintenance PD require a minimum protein intake of 1.0-1.2kg(-1) IBW per day, in conjunction with an adequate energy intake. There were no studies that addressed the quality of protein for either HD or PD. Evidence suggests that nutritional status may be maintained with lower protein intakes than previously recommended. However, the evidence base is limited and further randomised controlled trials are required to establish the optimal protein intake for dialysis patients.

Identifying recommended dietary allowances for protein and amino acids: a critique of the 2007 WHO/FAO/UNU report

The WHO/FAO/UNU (2007) report examines dietary protein and amino acid requirements for all age groups, protein requirements during pregnancy, lactation and catch-up growth in children, the implications of these requirements for developing countries and protein quality evaluation. Requirements were defined as the minimum dietary intake which satisfies the metabolic demand and achieves nitrogen equilibrium and maintenance of the body protein mass, plus the needs for growth in children and pregnancy and lactation in healthy women. Insufficient evidence was identified to enable recommendations for specific health outcomes. A meta analysis of nitrogen balance studies identifies protein requirements for adults 10 % higher than previous values with no influence of gender or age, consistent with a subsequently published comprehensive study. A new factorial model for infants and children, validated on the basis of the adequacy of breast milk protein intakes and involving a lower maintenance requirement value, no provision for saltatory growth and new estimates of protein deposition identifies lower protein requirements than in previous reports. Higher values for adult amino acid requirements, derived from a re-evaluation of nitrogen balance studies and new stable isotope studies, identify some cereal-based diets as being inadequate for lysine. The main outstanding issues relate to the biological implausibility of the very low efficiencies of protein utilisation used in the factorial models for protein requirements for all population groups especially pregnancy when requirements may be overestimated. Also considerable uncertainty remains about the design and interpretation of most of the studies used to identify amino acid requirement values.

Proteasome production in human muscle during nutritional inhibition of myofibrillar protein degradation

Protein undernutrition inhibits adenosine triphosphate (ATP)-dependent muscle protein degradation—a hallmark of the proteasome system. Here we report decreased myofibrillar protein degradation during dietary protein restriction without a concomitant decrease in proteasome gene expression, proteasome protein abundance, or proteasome in vivo fractional synthesis rate. Healthy human subjects consuming the average minimum adult protein requirement (0.71 g · kg −1 fat-free mass · d −1) exhibited substantially lower (68%) excretion of 3-methylhistidine, an indicator of myofibrillar protein breakdown, when compared with subjects consuming an ample, American-style protein intake (1.67 g · kg −1 fat-free mass · d −1). However, they displayed no difference in the expression of mRNA for proteasome subunits C2 or C3, in the content of C2 protein, or in the rate of incorporation of stable isotopically labeled l-[1- 13 C]-leucine into proteasome proteins. The results demonstrate that nutritional inhibition of myofibrillar protein degradation does not involve suppression in vivo of proteasome production in man. This suggests that other elements of the ubiquitin-proteasome system, such as ubiquitination pathways, are more important than proteasome abundance in the nutritional regulation of skeletal muscle mass.

Isoenergetic Dietary Protein Restriction Decreases Myosin Heavy Chain IIx Fraction and Myosin Heavy Chain Production in Humans

The synthesis of muscle protein is restrained during dietary protein restriction. This is widely understood to vary quantitatively with the degree of nutritional deprivation, but there has been little discussion of qualitative changes in muscle protein deriving from dietary protein restriction. We studied 14 healthy subjects in a 2-sample study. Subjects were randomly assigned to a diet providing an ample, American-style protein intake (1.67 g. kg fat-free mass(-1). d(-1)) or a diet approximating the mean minimum adult protein requirement (0.71 g. kg fat-free mass(-1). d(-1)). We found that consumption of an isoenergetic diet at the mean adult minimum protein requirement for 4 wk produced an 81% lower fractional synthesis rate of myosin heavy chain (MHC) proteins in vastus lateralis muscle than did consumption of an ample protein diet (P = 0.05). Protein deprivation altered the skeletal muscle myosin composition such that the proportion of the total myosin content represented by fast-twitch MHC IIx was 51% lower than with ample intake (P = 0.013). The steady state content of MHC IIx messenger RNA (mRNA) did not differ in subjects consuming the minimum requirement of protein, suggesting that the reduced proportion of MHC IIx arises from posttranscriptional events. A 68% lower rate of 3-methylhistidine excretion with protein restriction (P < 0.01) suggests that myofibrillar protein degradation was lower. We conclude that dietary amino acid scarcity produces a change in myosin isoform distribution via posttranscriptional mechanisms. The relative contribution of inhibited myosin synthesis and inhibited degradation to the altered myosin isoform composition remains unknown. This has implications for the mechanisms by which amino acids govern muscle protein composition in vivo, and further exploration is required.

Recommended daily exercise for Japanese does not increase the protein requirement in sedentary young men.

In a previous study, we reported that protein intake at the level of dietary protein allowance for Japanese adults, i.e. 1.08 g/kg per day, was enough for recommended daily exercise. However, whether or not recommended daily exercise increases the protein requirement for young adults has not been examined. In this study, we investigated the effect of recommended daily exercise on the protein requirement under an isoenergetic state by a nitrogen balance method. After an adaptation period of 3 days, 12 healthy college students exercised for 10 days with a non-exercise control period of 10 days before or after the exercise period. They were given a maintenance level of energy and 0.64 g/kg per day of high-quality mixed proteins, estimated as the average protein requirement for adults by the Ministry of Health and Welfare of Japan, throughout the experimental period. They performed treadmill running during the exercise period at about 65% of VO2 max for 25 or 40 min/d, which expended 200 or 300 kcal of extra energy, respectively. Although the exercise increased the dermal nitrogen loss, a compensatory decrease in urinary nitrogen excretion was observed. Consequently, the exercises (200 and 300 kcal/d) did not significantly affect the nitrogen balance. These findings indicate that the recommended amount of daily exercise does not change the protein requirement.

Protein requirements of adults from an evolutionary perspective

Protein requirements of adults from an evolutionary perspective

Protein requirements of adults from an evolutionary perspective

It is argued that the observed minimum needs for protein and individual amino acids by adult humans and animals may merely reflect the diet that their predecessors consumed in the course of their evolution. The ability to adapt to diets with a lower proportion of protein than was ever encountered in practice would have given no competitive advantage. This can explain the limited ability to reduce rates of amino acid catabolism. The protein requirement of domestic cats, obligate carnivores, corresponds to approximately 20% of their energy requirement. Humans adapt to lower levels (approximately 6%). Some urge that higher protein intakes, resulting in higher rates of protein synthesis and turnover, are desirable and that, in general, the more prosperous and successful groups eat more protein. But cause and effect may be reversed. Are higher rates of turnover and catabolism necessarily beneficial? Objective data are still not available.

Minimum Protein Requirements of Adults

Minimum Protein Requirements of Adults

Protein Requirements of Adults

Protein Requirements of Adults

Protein Requirements of Adults

Protein Requirements of Adults

Protein requirements of adults.

Abstract 1.1. Nitrogen balance studies on twenty-six adults in apparent good health were made using a low protein diet, devoid of animal protein, in which approximately 50 per cent of the protein was supplied by white bread, 12 per cent by other cereals, 30 per cent by vegetables, and 8 per cent by fruit. Adequate calories to maintain caloric equilibrium were supplied by sugars, starch, and fats. It was found that the nitrogen requirement is more closely related to surface area (basal caloric expenditure) than to body weight. The requirement for maintaining nitrogen balance was approximately 2.9 Gm. of nitrogen (18 Gm. conventional protein) per square meter of body surface. A man weighing 70 kilograms would thus require between 30 and 40 Gm. of protein, depending upon height. 2.2. On the same diet with one-third of the protein replaced by meat, the requirement appears to be about 2.4 Gm. nitrogen (15 Gm. conventional protein) per square meter. Protein requirement is thus about 17 per cent less on this diet than on the all-vegetable diet. 3.3. Data on digestibility and biologic value were determined and the equal importance of these two measurements for evaluating the nutritional value of a protein is emphasized. High quality proteins are more efficient, but less efficient proteins may serve equally well, provided enough can be fed to cover the requirement considering the specific digestibility and biologic value. 4.4. The biologic value of the low protein all-vegetable diet used in these studies was increased from 72.5 to 80.4 by replacing one-third of the protein with meat. The digestibility of the two diets was essentially the same. 5.5. There was no measurable objective change in the physical condition of any of the individuals throughout these studies. Some complained of undue postprandial hunger and fatigue on the low protein all-vegetable diets. These complaints were not present on high protein diets. 6.6. There were no significant changes in hemoglobin, hematocrit, or plasma volume. Total protein, plasma albumin, and plasma globulin tended to decrease on the low protein all-vegetable diet when fed at a level low enough to produce negative nitrogen balance. The replacement of one-third of the protein in this diet with meat resulted in a prompt increase in the globulin fraction. 7.7. It is most unlikely that protein deficiency will develop in apparently healthy adults on a diet in which cereals and vegetables supply adequate calories. 8.8. Considering the experimental data presented in this study, the National Research Council's daily recommended allowance of 70 Gm. of protein for an adult weighing 70 kilograms is most generous and could, if necessary, be reduced to 50 Gm. and still provide approximately 30 per cent margin above requirement. 9.9. It should be emphasized that the experimental data and the conclusions of this paper apply to adults in apparent good health and do not consider protein requirements in growth, pregnancy, lactation, or disease.