scholarly journals Dietary protein requirements and adaptive advantages in athletes

2012 ◽  
Vol 108 (S2) ◽  
pp. S158-S167 ◽  
Author(s):  
Stuart M. Phillips
Keyword(s):  
G Protein ◽  
Nitrogen Balance ◽  
Dietary Protein ◽  
Daily Intake ◽  
Dietary Guidelines ◽  
Protein Requirements ◽  
Dietary Reference Intakes ◽  
The Us ◽  
Nitrogen Intake ◽  
Practical Recommendations

Dietary guidelines from a variety of sources are generally congruent that an adequate dietary protein intake for persons over the age of 19 is between 0·8–0·9 g protein/kg body weight/d. According to the US/Canadian Dietary Reference Intakes, the RDA for protein of 0·8 g protein/kg/d is “…the average daily intake level that is sufficient to meet the nutrient requirement of nearly all [~98 %]… healthy individuals…” The panel also states that “…no additional dietary protein is suggested for healthy adults undertaking resistance or endurance exercise.” These recommendations are in contrast to recommendations from the US and Canadian Dietetic Association: “Protein recommendations for endurance and strength trained athletes range from 1·2 to 1·7 g/kg/d.” The disparity between those setting dietary protein requirements and those who might be considered to be making practical recommendations for athletes is substantial. This may reflect a situation where an adaptive advantage of protein intakes higher than recommended protein requirements exists. That population protein requirements are still based on nitrogen balance may also be a point of contention since achieving balanced nitrogen intake and excretion likely means little to an athlete who has the primary goal of exercise performance. The goal of the present review is to critically analyse evidence from both acute and chronic dietary protein-based studies in which athletic performance, or correlates thereof, have been measured. An attempt will be made to distinguish between protein requirements set by data from nitrogen balance studies, and a potential adaptive ‘advantage’ for athletes of dietary protein in excess of the RDA.

A Critical Examination of Dietary Protein Requirements, Benefits, and Excesses in Athletes

2007 ◽  
Vol 17 (s1) ◽  
pp. S58-S76 ◽  
Author(s):  
Stuart M. Phillips ◽  
Daniel R. Moore ◽  
Jason E. Tang
Keyword(s):  
Body Weight ◽  
Web Sites ◽  
Dietary Protein ◽  
Protein Intake ◽  
Common Ground ◽  
Daily Intake ◽  
Current Data ◽  
Dietary Guidelines ◽  
Critical Examination ◽  
Protein Requirements

There is likely no other dietary component that inspires as much debate, insofar as athletes are concerned, as protein. How much dietary protein is required, optimal, or excessive? Dietary guidelines from a variety of sources have settled on an adequate dietary protein intake for those over the age of 19 of ~0.8–0.9 g protein·kg body weight−1·d−1. According to U.S. and Canadian dietary reference intakes (33), the recommended allowance for protein of 0.8 g protein·kg−1·d−1 is “the average daily intake level that is sufficient to meet the nutrient requirement of nearly all [~98%] . . . healthy individuals” (p. 22). The panel also stated, “in view of the lack of compelling evidence to the contrary, no additional dietary protein is suggested for healthy adults undertaking resistance or endurance exercise” (33, p. 661). Currently, no group or groups of scientists involved in establishing dietary guidelines see a need for any statement that athletes or people engaging in regular physical activity require more protein than their sedentary counterparts. Popular magazines, numerous Web sites, trainers, and many athletes decry protein intakes even close to those recommended. Even joint position stands from policy-setting groups state that “protein recommendations for endurance athletes are 1.2 to 1.4 g/kg body weight per day, whereas those for resistance and strength-trained athletes may be as high as 1.6 to 1.7 g/kg body weight per day” (1, p. 1544). The divide between those setting dietary protein requirements and those who might be making practical recommendations for athletes appears substantial, but ultimately, most athletes indicate that they consume protein at levels beyond even the highest recommendations. Thus, one might conclude that any debate on protein “requirements” for athletes is inconsequential; however, a critical analysis of existing and new data reveals novel ideas and concepts that may represent some common ground between these apparently conflicted groups. The goal of this review was to provide a critical and thorough analysis of current data on protein requirements in an attempt to provide some guidance to athletes, trainers, coaches, and sport dietitians on athletes’ protein intake. In addition, an effort was made to clearly distinguish between “required” dietary protein, “optimal” intakes, and intakes that are likely “excessive,” perhaps not from the standpoint of health, but certainly from the standpoint of potentially compromised performance.

scholarly journals The Role of Fortified and Enriched Refined Grains in the US Dietary Pattern: A NHANES 2009–2016 Modeling Analysis to Examine Nutrient Adequacy

2021 ◽  
Vol 8 ◽  
Author(s):  
Yanni Papanikolaou ◽  
Victor L. III Fulgoni
Keyword(s):  
Older Adults ◽  
Dietary Fiber ◽  
Dietary Pattern ◽  
Daily Intake ◽  
Dietary Guidelines ◽  
Refined Grains ◽  
Old Adults ◽  
Nutrient Adequacy ◽  
Modeling Analysis ◽  
The Us

Background: While dietary recommendations call for greater whole-grain intake and reduced refined grain consumption, there are limited peer-reviewed studies examining the influence of fortified/enriched refined grains on nutrient adequacy.Methods: A modeling analysis using data from National Health and Nutrition Examination Survey (NHANES) 2009–2016 estimated usual daily intake of shortfall nutrients for Dietary Guidelines for Americans (DGA) in the current dietary pattern and when specific percentages of fortified/enriched refined grain foods (bread, ready-to-eat cereals, and all-grained foods) were removed from the diet (19–50-year-old adults, N = 11,169; 51–99-year-old adults, N = 9,641).Results: While American adults are currently falling short of nutrient recommendations, eliminating 25, 50, and 100% of all grains consumed in the US dietary pattern resulted in a greater percentage of adults not meeting recommendations for several shortfall nutrients, including dietary fiber, folate DFE, iron, and magnesium. Removal of all grains led to a reduced energy intake by ~10% in both age groups examined. Currently, ~3.8% of 19–50-year-old adults meet the adequate intake (AI) for dietary fiber. Removal of 25, 50, and 100% of grains from the diet resulted in 2.6 ± 0.3, 1.8 ± 0.2, and 0.7 ± 0.1% of adults exceeded the AI for dietary fiber, respectively. Similarly, 11.0 and 13.8% of younger and older adults, respectively, fall short of folate, DFE recommendations with the current diet. Following the removal of 100% of grains from the diet, 43.4 ± 1.1 and 56.2 ± 1.0%, respectively, were below the estimated average requirement (EAR) for folate DFE. For iron, current dietary pattern consumption shows 8.4% and 0.8% of younger and older adults, respectively, are not meeting iron recommendations, however, removal of 100% of grains from the diet results in nearly 10 and 22% falling short of the EAR. Currently, about 51 and 54% of younger and older adults are below the EAR for magnesium; however, with the removal of 100% of grains, 68 and 73%, respectively, fall below the EAR.Conclusion: Removal of specific refined grains led to an increased percentage of Americans not meeting recommendations for several shortfall nutrients, including dietary fiber, folate, iron, and magnesium.

scholarly journals Comparison of responses to dietary protein and lysine in broiler chicks reared before and after 2000 via neural network models

2012 ◽  
Vol 150 (6) ◽  
pp. 775-786 ◽  
Author(s):  
A. FARIDI ◽  
A. GOLIAN ◽  
H. AHMADI
Keyword(s):  
Sensitivity Analysis ◽  
G Protein ◽  
Dietary Protein ◽  
Average Daily Gain ◽  
Network Models ◽  
Broiler Chicks ◽  
Data Sets ◽  
Neural Network Models ◽  
Protein Requirements ◽  
Before And After

SUMMARYThe current study was conducted to compare the responses of broiler chicks (average daily gain (ADG) and feed efficiency (FE)) raised before and after 2000 to dietary protein and lysine through neural networks (NN). The available lysine dose-response data were extracted from the literature and arbitrarily divided into two sets of before and after 2000. The training and testing data sets derived from each group were used to develop the NN models. The developed models were subjected to a sensitivity analysis test to assess the relative importance of dietary protein and lysine on chicks’ responses. An optimization algorithm was used to find the dietary protein and lysine required for maximum ADG and FE, based on each dataset. The results showed that the NN models developed could predict ADG and FE efficiently in broiler chicks of before and after 2000, and the higher accuracies of prediction were attained by these models compared to those of regression models. Sensitivity analysis indicated that ADG and FE were more sensitive to dietary lysine, compared to protein, in both time periods. Based on the optimization results, the protein and lysine requirements for maximum ADG or FE for birds reared after 2000 were lower and higher, respectively, compared to those reared before 2000. The protein requirements for maximum ADG and FE for birds reared before 2000 were 241·3 and 247·0 g/kg diet and for lysine 10·76 and 11·18 g/kg diet, respectively. In birds reared after 2000, maximum ADG was obtained when the diet contained 224·30 g protein/kg diet and 11·75 g lysine/kg diet, whereas maximum FE was achieved with a diet containing 228·3 g protein and 13·1 g lysine.

A snapshot of nitrogen balance in endurance-trained women

2014 ◽  
Vol 39 (2) ◽  
pp. 219-225 ◽  
Author(s):  
Stuart Douglas Houltham ◽  
David S. Rowlands
Keyword(s):  
Nitrogen Balance ◽  
Dietary Protein ◽  
Nitrogen Loss ◽  
Fold Increase ◽  
Food Samples ◽  
Follicular Phase ◽  
Protein Requirement ◽  
Nitrogen Intake ◽  
The Mean ◽  
Urinary Nitrogen

Indirect estimates of the mean daily protein requirement for female endurance athletes are 1.2–1.4 g·kg−1·day−1; however, an empirical estimate using nitrogen balance is absent. A 72-h nitrogen balance was determined during the mid-follicular phase of 10 female cyclists and triathletes training for 10.8 h·week−1 (SD 2.8) following 2 habituated protein intakes: (i) normal habitual (NH) (protein 85 g·day−1), and (ii) isocaloric high-protein (HP) (∼2-fold increase in protein). Total 72-h nitrogen intake was determined from Leco total combustion of ingested food samples. Nitrogen loss was determined from micro-Kjeldahl analysis of 72-h total urinary nitrogen and representative resting and exercise sweat output, plus estimates for fecal and miscellaneous losses. Habituated (steady state) protein requirement was estimated from the mean regression of adapted nitrogen balance vs nitrogen intake. Mean (SD) 24-h dietary protein and energy intake was NH: 1.4 g·kg−1·day−1 (0.2), energy: 9078 kJ·day−1 (1492), HP: 2.7 g·kg−1·day−1 (0.3) 8909 kJ·day−1 (1411). Average 24-h urinary nitrogen and sweat urea nitrogen outputs were 13.2 g·day−1 (2.4) and 0.33 g·day−1 (0.08) in NH; 21.5 g·day−1 (3.9) and 0.54 g·day−1 (0.12) in HP, respectively. Nitrogen balance was negative in NH (−0.59 gN·day−1 SD 1.64) but positive in HP (2.69 gN·day−1 SD 3.09). Estimated mean protein requirement was 1.63 g·kg−1·day−1 (95% confidence interval: 1.1–3.8). In conclusion the snapshot of follicular phase dietary protein requirement conformed with previous estimates for men, but was higher than previous nonempirical estimates for endurance-training women; low self-selected energy and carbohydrate intakes may explain the higher than expected nitrogen turnover, and consequently protein requirement.

scholarly journals Longitudinal analysis of intervention effects on temptations and stages of change for dietary fat using parallel process latent growth modeling

2016 ◽  
Vol 24 (5) ◽  
pp. 572-585 ◽  
Author(s):  
Leslie Ann D Brick ◽  
Si Yang ◽  
Lisa L Harlow ◽  
Colleen A Redding ◽  
James O Prochaska
Keyword(s):  
Stages Of Change ◽  
Daily Intake ◽  
Rate Of Change ◽  
Dietary Guidelines ◽  
High Fat ◽  
Latent Growth ◽  
Intervention Effects ◽  
Randomized Controlled ◽  
Stage Of Readiness ◽  
Dietary Guidelines For Americans

The Dietary Guidelines for Americans recommend a 20–35 percent daily intake of fat. Resisting the temptation to eat high-fat foods, in conjunction with stage of readiness to avoid these foods, has been shown to influence healthy behavior change. Data ( N = 6516) from three randomized controlled trials were pooled to examine the relationships among direct intervention effects on temptations and stage of change for limiting high-fat foods. Findings demonstrate separate simultaneous growth processes in which baseline level of temptations, but not the rate of change in temptations, was significantly related to the change in readiness to avoid high-fat foods.

Utilization of grass-silage nitrogen by growing sheep

1983 ◽  
Vol 100 (1) ◽  
pp. 43-62 ◽  
Author(s):  
Elisabeth Grenet
Keyword(s):  
Organic Matter ◽  
Formic Acid ◽  
Nitrogen Balance ◽  
Crude Protein ◽  
Nitrogen Loss ◽  
Nitrogen Retention ◽  
Protein Digestibility ◽  
Water Soluble ◽  
Nitrogen Intake ◽  
Green Fodder

SUMMARYThe digestibility, the voluntary intake and the nitrogen balance of 108 diets corresponding to 94 silages prepared from 20 fresh crops were measured in growing sheep. Series of silages were made from the same fresh forage. Each series included two controls: a direct-cut silage without additive and a direct-cut silage with formic acid, with a variable number of experimental silages with different additives.Rumen ammonia concentration, measured on rumen-fistulated sheep, decreased when an additive was used. It increased with nitrogen intake and was inversely related to the organic-matter digestibility and the crude-fibre digestibility. It varied with the silage composition.The crude-protein digestibility of direct-cut silages without additives was similar to or slightly higher than the crude-protein digestibility of the fresh crops. The addition of formic acid depressed the digestibility, but the addition of formaldehyde decreased it even more. The urinary nitrogen loss was higher for silages without additive than for the fresh crops and was decreased by the addition of formic acid. The addition of formaldehyde to formic acid had an additive effect.Retained nitrogen was lower in silages without additives (12% of nitrogen intake) than in parent crops (15·7%). It increased when formic acid (15·8%) was added. The addition of formaldehyde at a low rate (1·5 l/t green fodder) to the formic acid did not increase the nitrogen retention whether expressed in g/day or as percentage of nitrogen intake, but the addition of formaldehyde at a high rate (3·5 l/t green fodder) to formic acid decreased nitrogen retention. The other additives based on cereals or whey did not improve the nitrogen balance compared with formic acid. Nitrogen retention differed according to plant species.Retained nitrogen increased with digestible organic-matter intake and nitrogen intake. It increased with the silage water-soluble carbohydrate content. The higher the silage fermentation product content (ammonia, lactic acid, propionic acid), the lower the retained nitrogen. It appears that the nitrogen value of silages can be high provided that the silages are well preserved and that excessive protein breakdown is avoided.

scholarly journals The carbon footprint of dietary guidelines around the world: a seven country modeling study

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Brittany Kovacs ◽  
Lindsey Miller ◽  
Martin C. Heller ◽  
Donald Rose
Keyword(s):  
The Netherlands ◽  
Carbon Footprint ◽  
The United States ◽  
Dietary Guidelines ◽  
Consumption Patterns ◽  
Consumption Pattern ◽  
Carbon Footprints ◽  
Country Level ◽  
The Us ◽  
The World

Abstract Background Do the environmental impacts inherent in national food-based dietary guidelines (FBDG) vary around the world, and, if so, how? Most previous studies that consider this question focus on a single country or compare countries’ guidelines without controlling for differences in country-level consumption patterns. To address this gap, we model the carbon footprint of the dietary guidelines from seven different countries, examine the key contributors to this, and control for consumption differences between countries. Methods In this purposive sample, we obtained FBDG from national sources for Germany, India, the Netherlands, Oman, Thailand, Uruguay, and the United States. These were used to structure recommended diets using 6 food groups: protein foods, dairy, grains, fruits, vegetables, and oils/fats. To determine specific quantities of individual foods within these groups, we used data on food supplies available for human consumption for each country from the UN Food and Agriculture Organization’s food balance sheets. The greenhouse gas emissions (GHGE) used to produce the foods in these consumption patterns were linked from our own database, constructed from an exhaustive review of the life cycle assessment literature. All guidelines were scaled to a 2000-kcal diet. Results Daily recommended amounts of dairy foods ranged from a low of 118 ml/d for Oman to a high of 710 ml/d for the US. The GHGE associated with these two recommendations were 0.17 and 1.10 kg CO2-eq/d, respectively. The GHGE associated with the protein food recommendations ranged from 0.03 kg CO2-eq/d in India  to 1.84 kg CO2-eq/d in the US, for recommended amounts of 75 g/d and 156 g/d, respectively. Overall, US recommendations had the highest carbon footprint at 3.83 kg CO2-eq/d, 4.5 times that of the recommended diet for India, which had the smallest footprint. After controlling for country-level consumption patterns by applying the US consumption pattern to all countries, US recommendations were still the highest, 19% and 47% higher than those of the Netherlands and Germany, respectively. Conclusions Despite our common human biology, FBDG vary tremendously from one country to the next, as do the associated carbon footprints of these guidelines. Understanding the carbon footprints of different recommendations can assist in future decision-making to incorporate environmental sustainability in dietary guidance.

RESPONSE OF EARLY WEANED PIGS TO DIETS OF DIFFERENT DIGESTIBLE ENERGY CONCENTRATIONS AND THE EFFECTS OF CEREAL SOURCE AND ADDED MOLASSES ON PERFORMANCE

1972 ◽  
Vol 52 (1) ◽  
pp. 87-96 ◽  
Author(s):  
J. F. O’GRADY ◽  
J. P. BOWLAND
Keyword(s):  
Growth Rate ◽  
G Protein ◽  
Dietary Protein ◽  
Lower Energy ◽  
Energy Levels ◽  
Constant Ratio ◽  
Initial Weight ◽  
N Retention ◽  
Digestible Energy ◽  
Very High

One hundred and sixty pigs weaned at 2 weeks were allotted at an average initial weight of 3.8 kg to two experiments to examine the effects of diets based on barley or wheat as the cereal component and having digestible energy (DE) concentrations ranging from 2.8 to 3.6 Mcal/kg. Protein was in constant ratio to DE (15.2 kcal DE/g protein). Very high mortality was experienced on the lower energy levels, although the inclusion of 5% molasses in the formulation reduced mortality. Among surviving pigs, growth rate was significantly reduced at lower energy concentrations. The optimum DE level for maximum gain was 3.2 Mcal in the first experiment and 3.4 Mcal/kg in the second. The efficiency of utilization of DE for growth was best at a DE concentration of 3.2 Mcal/kg in the first experiment but did not vary in the second. Digestibility of dietary protein increased with increasing dietary DE but nitrogen (N) retention as percentage of N intake or of digestible N was not significantly influenced by DE in the diet.

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