Nutritional Requirements for Sustaining Health and Performance During Exposure to Extreme Environments

Pasiakos, Stefan M.

doi:10.1146/annurev-nutr-011720-122637

Cited by 19 publications

(31 citation statements)

References 121 publications

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“…Harsh environments elicit a plethora of specific physiological adaptations, alter body composition, performance and require special nutritional requirements [ 1 ]. As altitude travelling is increasing, novel insights about the specific adaptations and requirements are needed.…”

Section: Introductionmentioning

confidence: 99%

“…Muscular distress provoked by a physical effort at high altitude affects body composition and activates pro-inflammatory pathways [ 16 ]. Distress in fluid balance is a typical response to high-altitude exposure, with an altered micturition habit and a loss of body fluids [ 1 , 17 ].…”

Section: Introductionmentioning

confidence: 99%

“…Into the topic of muscular examination, muscle ultrasound has been demonstrated as a useful, non-invasive, feasible and reliable tool across all the ages [ 20 , 21 ]. The body water and muscle mass loss during and after altitude exposure linked to the altered nutritional requirements [ 1 ] supports the need for quantitative assessments of intake during the expeditions.…”

Section: Introductionmentioning

confidence: 99%

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Feeding Your Himalayan Expedition: Nutritional Signatures and Body Composition Adaptations of Trekkers and Porters

et al. 2021

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High-altitude exposure leads to many physiological challenges, such as weight loss and dehydration. However, little attention has been posed to the role of nutrition and ethnic differences. Aiming to fulfill this gap, five Italian trekkers and seven Nepalese porters, all males, recorded their diet in diaries during a Himalayan expedition (19 days), and the average daily intake of micro and macro-nutrients were calculated. Bioimpedance analysis was performed five times during the trek; muscle ultrasound was performed before and after the expedition, only for the Italians. The Nepalese group consumed a lot of rice and only Italians consumed cheese. Water intake was slightly over 3000 g/d for both groups. Nepalese diet had a higher density of dietary fibre and lower density of riboflavin, vitamins A, K, and B12. Intake of calcium was lower than recommended levels. Body mass index, waist circumference, fat-free mass, and total body water decreased in both groups, whereas resistance (Rz) increased. Italians reactance (Xc) increased at day 9, whereas that of Nepalese occurred at days 5, 9, and 16. The cross-sectional area of the Vastus lateralis was reduced after the expedition. Specific nutritional and food-related risk factors guidance is needed for diverse expedition groups. Loss of muscle mass and balance of fluids both deserve a particular focus as concerns altitude expeditions.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Feeding Your Himalayan Expedition: Nutritional Signatures and Body Composition Adaptations of Trekkers and Porters

et al. 2021

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“…However, the elevations in circulating EAA provided precursor amino acids to meet whole-body protein synthesis requirements, which likely contributed to a reduction in the reliance on whole-body protein breakdown to supply precursor amino acids [ 77 , 78 ]. The effect on whole-body protein balance is particularly significant when considering the importance of preventing or attenuating extensive whole-body protein breakdown (i.e., beyond the breakdown required for normal tissue maintenance and repair) and related body protein loss during energy deficit [ 79 ]. As stated, muscle is not the priority tissue during catabolic stress.…”

Section: Maximizing Mps and Whole-body Protein Status During Energmentioning

confidence: 99%

“…Feeding strategies under these conditions must leverage formats that deliver optimal amino acid quantity and composition within a highly digestible and absorbable food format. As stated, military personnel are one example of an otherwise healthy population consistently exposed to multiple catabolic stressors including energy deficit [ 79 ]. Military personnel generally subsist on combat food rations during strenuous, sustained trainings and operations that elicit moderate to severe energy deficits.…”

Section: Knowledge Gaps Surrounding Protein and Eaa Formats To Supmentioning

confidence: 99%

Muscle Protein Synthesis and Whole-Body Protein Turnover Responses to Ingesting Essential Amino Acids, Intact Protein, and Protein-Containing Mixed Meals with Considerations for Energy Deficit

et al. 2020

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Protein intake recommendations to optimally stimulate muscle protein synthesis (MPS) are derived from dose-response studies examining the stimulatory effects of isolated intact proteins (e.g., whey, egg) on MPS in healthy individuals during energy balance. Those recommendations may not be adequate during periods of physiological stress, specifically the catabolic stress induced by energy deficit. Providing supplemental intact protein (20–25 g whey protein, 0.25–0.3 g protein/kg per meal) during strenuous military operations that elicit severe energy deficit does not stimulate MPS-associated anabolic signaling or attenuate lean mass loss. This occurs likely because a greater proportion of the dietary amino acids consumed are targeted for energy-yielding pathways, whole-body protein synthesis, and other whole-body essential amino acid (EAA)-requiring processes than the proportion targeted for MPS. Protein feeding formats that provide sufficient energy to offset whole-body energy and protein-requiring demands during energy deficit and leverage EAA content, digestion, and absorption kinetics may optimize MPS under these conditions. Understanding the effects of protein feeding format-driven alterations in EAA availability and subsequent changes in MPS and whole-body protein turnover is required to design feeding strategies that mitigate the catabolic effects of energy deficit. In this manuscript, we review the effects, advantages, disadvantages, and knowledge gaps pertaining to supplemental free-form EAA, intact protein, and protein-containing mixed meal ingestion on MPS. We discuss the fundamental role of whole-body protein balance and highlight the importance of comprehensively assessing whole-body and muscle protein kinetics when evaluating the anabolic potential of varying protein feeding formats during energy deficit.

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New Horizons in Carbohydrate Research and Application for Endurance Athletes

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Wallis

2022

Sports Med

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The importance of carbohydrate as a fuel source for exercise and athletic performance is well established. Equally well developed are dietary carbohydrate intake guidelines for endurance athletes seeking to optimize their performance. This narrative review provides a contemporary perspective on research into the role of, and application of, carbohydrate in the diet of endurance athletes. The review discusses how recommendations could become increasingly refined and what future research would further our understanding of how to optimize dietary carbohydrate intake to positively impact endurance performance. High carbohydrate availability for prolonged intense exercise and competition performance remains a priority. Recent advances have been made on the recommended type and quantity of carbohydrates to be ingested before, during and after intense exercise bouts. Whilst reducing carbohydrate availability around selected exercise bouts to augment metabolic adaptations to training is now widely recommended, a contemporary view of the so-called train-low approach based on the totality of the current evidence suggests limited utility for enhancing performance benefits from training. Nonetheless, such studies have focused importance on periodizing carbohydrate intake based on, among other factors, the goal and demand of training or competition. This calls for a much more personalized approach to carbohydrate recommendations that could be further supported through future research and technological innovation (e.g., continuous glucose monitoring). Despite more than a century of investigations into carbohydrate nutrition, exercise metabolism and endurance performance, there are numerous new important discoveries, both from an applied and mechanistic perspective, on the horizon.

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Nutritional Requirements for Sustaining Health and Performance During Exposure to Extreme Environments

Cited by 19 publications

References 121 publications

Feeding Your Himalayan Expedition: Nutritional Signatures and Body Composition Adaptations of Trekkers and Porters

Feeding Your Himalayan Expedition: Nutritional Signatures and Body Composition Adaptations of Trekkers and Porters

Muscle Protein Synthesis and Whole-Body Protein Turnover Responses to Ingesting Essential Amino Acids, Intact Protein, and Protein-Containing Mixed Meals with Considerations for Energy Deficit

New Horizons in Carbohydrate Research and Application for Endurance Athletes

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