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The American Journal of Clinical... Mar 2016A dietary protein intake higher than the Recommended Dietary Allowance during an energy deficit helps to preserve lean body mass (LBM), particularly when combined with... (Comparative Study)
Comparative Study Randomized Controlled Trial
BACKGROUND
A dietary protein intake higher than the Recommended Dietary Allowance during an energy deficit helps to preserve lean body mass (LBM), particularly when combined with exercise.
OBJECTIVE
The purpose of this study was to conduct a proof-of-principle trial to test whether manipulation of dietary protein intake during a marked energy deficit in addition to intense exercise training would affect changes in body composition.
DESIGN
We used a single-blind, randomized, parallel-group prospective trial. During a 4-wk period, we provided hypoenergetic (~40% reduction compared with requirements) diets providing 33 ± 1 kcal/kg LBM to young men who were randomly assigned (n = 20/group) to consume either a lower-protein (1.2 g · kg(-1) · d(-1)) control diet (CON) or a higher-protein (2.4 g · kg(-1) · d(-1)) diet (PRO). All subjects performed resistance exercise training combined with high-intensity interval training for 6 d/wk. A 4-compartment model assessment of body composition was made pre- and postintervention.
RESULTS
As a result of the intervention, LBM increased (P < 0.05) in the PRO group (1.2 ± 1.0 kg) and to a greater extent (P < 0.05) compared with the CON group (0.1 ± 1.0 kg). The PRO group had a greater loss of fat mass than did the CON group (PRO: -4.8 ± 1.6 kg; CON: -3.5 ± 1.4kg; P < 0.05). All measures of exercise performance improved similarly in the PRO and CON groups as a result of the intervention with no effect of protein supplementation. Changes in serum cortisol during the intervention were associated with changes in body fat (r = 0.39, P = 0.01) and LBM (r = -0.34, P = 0.03).
CONCLUSIONS
Our results showed that, during a marked energy deficit, consumption of a diet containing 2.4 g protein · kg(-1) · d(-1) was more effective than consumption of a diet containing 1.2 g protein · kg(-1) · d(-1) in promoting increases in LBM and losses of fat mass when combined with a high volume of resistance and anaerobic exercise. Changes in serum cortisol were associated with changes in body fat and LBM, but did not explain much variance in either measure. This trial was registered at clinicaltrials.gov as NCT01776359.
Topics: Adipose Tissue; Adult; Body Composition; Body Fluid Compartments; Caloric Restriction; Diet; Dietary Proteins; Energy Intake; Exercise; Humans; Hydrocortisone; Male; Nutritional Requirements; Physical Exertion; Prospective Studies; Resistance Training; Single-Blind Method; Young Adult
PubMed: 26817506
DOI: 10.3945/ajcn.115.119339 -
Current Opinion in Clinical Nutrition... May 2015We provide an update on the recent advances in nutrition research regarding the role of protein intake in the development and treatment of sarcopenia of aging. (Review)
Review
PURPOSE OF REVIEW
We provide an update on the recent advances in nutrition research regarding the role of protein intake in the development and treatment of sarcopenia of aging.
RECENT FINDINGS
Specific muscle mass, strength and function cut-points for the diagnosis of sarcopenia have been identified. There is mounting evidence, as highlighted by multiple consensus statements, that the Recommended Dietary Allowance (0.8 g/kg body weight) may be inadequate to promote optimal health in older adults. Recent research indicates that in addition to total daily protein intake the timing of protein intake is also important to best stimulate muscle protein synthesis, and maintain muscle mass and function in older adults.
SUMMARY
Recent evidence suggests that the Recommended Dietary Allowance for protein is inadequate, and that the timing and distribution of protein consumption throughout daily meals may be as important as the total quantity. Research has continued to advance our understanding of protein's effects on muscle metabolism; however, there remains a need for large, long-term, randomized clinical trials examining whether the positive effects of dietary protein on muscle metabolism seen in acute studies will translate over the long term into gains of muscle mass, function, and the overall health of older adults.
Topics: Aged; Aging; Body Composition; Diet; Dietary Proteins; Humans; Muscle Proteins; Muscle, Skeletal; Nutritional Requirements; Sarcopenia
PubMed: 25807346
DOI: 10.1097/MCO.0000000000000162 -
Nutrients Jun 2020Protein is an important component of a healthy diet and appears to be integral to enhancing training adaptations in exercising individuals. The purpose of this narrative... (Review)
Review
Protein is an important component of a healthy diet and appears to be integral to enhancing training adaptations in exercising individuals. The purpose of this narrative review is to provide an evidence-based assessment of the current literature examining increases in dietary protein intake above the recommended dietary allowance (RDA: 0.8 g/kg/d) in conjunction with chronic exercise on body composition (i.e., muscle, fat and bone). We also highlight acute and chronic pre-sleep protein studies as well as the influence of exercise timing on body composition. Overall, a high-protein diet appears to increase muscle accretion and fat loss and may have beneficial effects on bone when combined with exercise. Pre-sleep protein is a viable strategy to help achieve total daily protein goals. Importantly, there appears to be no deleterious effects from a high-protein diet on muscle, fat or bone in exercising individuals.
Topics: Adipose Tissue; Adolescent; Adult; Body Composition; Bone and Bones; Diet, High-Protein; Dietary Proteins; Exercise; Female; Humans; Male; Muscle, Skeletal; Sleep; Time Factors; Young Adult
PubMed: 32630466
DOI: 10.3390/nu12061890 -
Current Protein & Peptide Science 2017There is growing recognition that composition and metabolic activity of the gut microbiota can be modulated by the dietary proteins which in turn impact health. The... (Review)
Review
There is growing recognition that composition and metabolic activity of the gut microbiota can be modulated by the dietary proteins which in turn impact health. The amino acid composition and digestibility of proteins, which are influenced by its source and amount of intake, play a pivotal role in determining the microbiota. Reciprocally, it appears that the gut microbiota is also able to affect protein metabolism which gives rise to the view that function between the microbiota and protein can proceed in both directions. In response to the alterations in dietary protein components, there are significant changes in the microbial metabolites including short chain fatty acids (SCFAs), ammonia, amines, gases such as hydrogen, sulfide and methane which are cytotoxins, genotoxins and carcinogens associated with development of colon cancer and inflammatory bowel diseases. A suitable ratio between protein and carbohydrate or even a low protein diet is recommended based on the evidence that excessive protein intake adversely affects health. Supplying high and undigested proteins will encourage pathogens and protein-fermenting bacteria to increase the risk of diseases. These changes of microbiota can affect the gut barrier and the immune system by regulating gene expression in relevant signaling pathways and by regulating the secretion of metabolites. The objective of this review is to assess the impact of dietary proteins on microbiota composition and activity in the gastrointestinal tract. Attention should be given to the dietary strategies with judicious selection of source and supplementation of dietary protein to benefit gut health.
Topics: Actinobacteria; Amines; Ammonia; Bacteroidetes; Dietary Carbohydrates; Dietary Proteins; Fatty Acids, Volatile; Fermentation; Firmicutes; Fusobacteria; Gastrointestinal Microbiome; Gastrointestinal Tract; Humans; Proteobacteria; Proteolysis; Verrucomicrobia
PubMed: 28215168
DOI: 10.2174/1389203718666170216153505 -
Nutrients Jun 2016Maintaining independence, quality of life, and health is crucial for elderly adults. One of the major threats to living independently is the loss of muscle mass,... (Review)
Review
Maintaining independence, quality of life, and health is crucial for elderly adults. One of the major threats to living independently is the loss of muscle mass, strength, and function that progressively occurs with aging, known as sarcopenia. Several studies have identified protein (especially the essential amino acids) as a key nutrient for muscle health in elderly adults. Elderly adults are less responsive to the anabolic stimulus of low doses of amino acid intake compared to younger individuals. However, this lack of responsiveness in elderly adults can be overcome with higher levels of protein (or essential amino acid) consumption. The requirement for a larger dose of protein to generate responses in elderly adults similar to the responses in younger adults provides the support for a beneficial effect of increased protein in older populations. The purpose of this review is to present the current evidence related to dietary protein intake and muscle health in elderly adults.
Topics: Aged; Aged, 80 and over; Aging; Amino Acids, Essential; Dietary Proteins; Energy Intake; Humans; Muscle, Skeletal; Nutritional Requirements
PubMed: 27338461
DOI: 10.3390/nu8060359 -
Nutrients May 2019Adequate consumption of dietary protein is critical for the maintenance of optimal health during normal growth and aging. The current Recommended Dietary Allowance (RDA)...
Adequate consumption of dietary protein is critical for the maintenance of optimal health during normal growth and aging. The current Recommended Dietary Allowance (RDA) for protein is defined as the minimum amount required to prevent lean body mass loss, but is often misrepresented and misinterpreted as a recommended optimal intake. Over the past two decades, the potential muscle-related benefits achieved by consuming higher-protein diets have become increasingly clear. Despite greater awareness of how higher-protein diets might be advantageous for muscle mass, actual dietary patterns, particularly as they pertain to protein, have remained relatively unchanged in American adults. This lack of change may, in part, result from confusion over the purported detrimental effects of higher-protein diets. This manuscript will highlight common perceptions and benefits of dietary protein on muscle mass, address misperceptions related to higher-protein diets, and comment on the translation of academic advances to real-life application and health benefit. Given the vast research evidence supporting the positive effects of dietary protein intake on optimal health, we encourage critical evaluation of current protein intake recommendations and responsible representation and application of the RDA as a minimum protein requirement rather than one determined to optimally meet the needs of the population.
Topics: Diet, Reducing; Dietary Proteins; Energy Intake; Exercise; Health Knowledge, Attitudes, Practice; Humans; Muscle, Skeletal; Nutritional Sciences; Recommended Dietary Allowances; Wasting Syndrome
PubMed: 31121843
DOI: 10.3390/nu11051136 -
Nutrients Apr 2019Sports nutrition products are developed and targeted mainly for athletes to improve their nutrient intake, performance, and muscle growth. The fastest growing consumer... (Review)
Review
Sports nutrition products are developed and targeted mainly for athletes to improve their nutrient intake, performance, and muscle growth. The fastest growing consumer groups for these products are recreational sportspeople and lifestyle users. Although athletes may have elevated physiological protein requirements and they may benefit from dietary supplements, the evidence regarding the role of dietary protein and supplements in the nutrition of recreational sportspeople and sedentary populations is somewhat complex and contradictory. In high-protein diets, more undigested protein-derived constituents end up in the large intestine compared to moderate or low-protein diets, and hence, more bacterial amino acid metabolism takes place in the colon, having both positive and negative systemic and metabolic effects on the host. The aim of the present review is to summarize the impact of the high-protein products and diets on nutrition and health, in sportspeople and in sedentary consumers. We are opening the debate about the current protein intake recommendations, with an emphasis on evidence-based effects on intestinal microbiota and personalized guidelines regarding protein and amino acid supplementation in sportspeople and lifestyle consumers.
Topics: Amino Acids; Bacteria; Dietary Proteins; Dietary Supplements; Digestion; Exercise; Gastrointestinal Microbiome; Humans; Intestine, Large; Nutritional Status; Recommended Dietary Allowances; Sedentary Behavior; Sports; Sports Nutritional Physiological Phenomena
PubMed: 31013719
DOI: 10.3390/nu11040829 -
Cell Sep 2022Great progress has been made in understanding gut microbiomes' products and their effects on health and disease. Less attention, however, has been given to the inputs...
Great progress has been made in understanding gut microbiomes' products and their effects on health and disease. Less attention, however, has been given to the inputs that gut bacteria consume. Here, we quantitatively examine inputs and outputs of the mouse gut microbiome, using isotope tracing. The main input to microbial carbohydrate fermentation is dietary fiber and to branched-chain fatty acids and aromatic metabolites is dietary protein. In addition, circulating host lactate, 3-hydroxybutyrate, and urea (but not glucose or amino acids) feed the gut microbiome. To determine the nutrient preferences across bacteria, we traced into genus-specific bacterial protein sequences. We found systematic differences in nutrient use: most genera in the phylum Firmicutes prefer dietary protein, Bacteroides dietary fiber, and Akkermansia circulating host lactate. Such preferences correlate with microbiome composition changes in response to dietary modifications. Thus, diet shapes the microbiome by promoting the growth of bacteria that preferentially use the ingested nutrients.
Topics: Animals; Bacteria; Diet; Dietary Fiber; Dietary Proteins; Gastrointestinal Microbiome; Lactates; Mice; Nutrients
PubMed: 36055202
DOI: 10.1016/j.cell.2022.07.020 -
The Journal of Experimental Medicine Aug 2023The intestinal immune system must tolerate food antigens to avoid allergy, a process requiring CD4+ T cells. Combining antigenically defined diets with gnotobiotic...
The intestinal immune system must tolerate food antigens to avoid allergy, a process requiring CD4+ T cells. Combining antigenically defined diets with gnotobiotic models, we show that food and microbiota distinctly influence the profile and T cell receptor repertoire of intestinal CD4+ T cells. Independent of the microbiota, dietary proteins contributed to accumulation and clonal selection of antigen-experienced CD4+ T cells at the intestinal epithelium, imprinting a tissue-specialized transcriptional program including cytotoxic genes on both conventional and regulatory CD4+ T cells (Tregs). This steady state CD4+ T cell response to food was disrupted by inflammatory challenge, and protection against food allergy in this context was associated with Treg clonal expansion and decreased proinflammatory gene expression. Finally, we identified both steady-state epithelium-adapted CD4+ T cells and tolerance-induced Tregs that recognize dietary antigens, suggesting that both cell types may be critical for preventing inappropriate immune responses to food.
Topics: CD4-Positive T-Lymphocytes; Intestines; T-Lymphocytes, Regulatory; Immune Tolerance; Antigens; Dietary Proteins
PubMed: 37191720
DOI: 10.1084/jem.20221816 -
Nutrients Feb 2023Since the U.S. Institute of Medicine's recommendations on protein and amino acid intake in 2005, new information supports the need to re-evaluate these recommendations.... (Review)
Review
Since the U.S. Institute of Medicine's recommendations on protein and amino acid intake in 2005, new information supports the need to re-evaluate these recommendations. New lines of evidence include: (1) re-analysis/re-interpretation of nitrogen balance data; (2) results from indicator amino acid oxidation studies; (3) studies of positive functional outcomes associated with protein intakes higher than recommended; (4) dietary guidance and protein recommendations from some professional nutrition societies; and (5) recognition that the synthesis of certain dispensable amino acids may be insufficient to meet physiological requirements more often than previously understood. The empirical estimates, theoretical calculations and clinical functional outcomes converge on a similar theme, that recommendations for intake of protein and some amino acids may be too low in several populations, including for older adults (≥65 years), pregnant and lactating women, and healthy children older than 3 years. Additional influential factors that should be considered are protein quality that meets operational sufficiency (adequate intake to support healthy functional outcomes), interactions between protein and energy intake, and functional roles of amino acids which could impact the pool of available amino acids for use in protein synthesis. Going forward, the definition of "adequacy" as it pertains to protein and amino acid intake recommendations must take into consideration these critical factors.
Topics: Child; Pregnancy; Humans; Female; Child, Preschool; Aged; Nutritional Requirements; Lactation; Amino Acids; Dietary Proteins; Energy Intake
PubMed: 36839196
DOI: 10.3390/nu15040838