Amino Acids, Fatigue and Immunodepression in Exercise

Newsholme, Eric A.; Castell, Linda M.

doi:10.1002/9780470693766.ch11

Cited by 8 publications

(6 citation statements)

References 78 publications

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“…In particular, it is proposed that, because the synthesis of 5-hydroxytryptamine is limited by availability of its precursor tryptophan, and because tryptophan uptake across the blood-brain barrier shares the same transporter as the branched-chain amino acids, an increase in circulating branched-chain amino acid concentration might delay the onset of fatigue (Davis, 2000). While there is some experimental support for the hypothesis of Newsholme & Castell (2000), the evidence of a beneficial effect on exercise performance is limited. Nonetheless, the fact that pharmacological manipulation of 5-hydroxytryptamine activity can alter exercise performance (Wilson & Maughan, 1992) does suggest that nutritional interventions to produce the same effect may also be possible.…”

Section: Central Nervous System Effectsmentioning

confidence: 99%

“…As most of the centrally acting drugs are not permitted by the governing bodies of sport, the scope is limited, but there has been interest in the use of branched-chain amino acids. Newsholme and colleagues (Newsholme & Castell, 2000) have proposed that fatigue may be mediated in part by the actions of 5-hydroxytryptamine (serotonin) in the brain, and that the synthesis and release of 5-hydroxytryptamine may be modulated by diet. In particular, it is proposed that, because the synthesis of 5-hydroxytryptamine is limited by availability of its precursor tryptophan, and because tryptophan uptake across the blood-brain barrier shares the same transporter as the branched-chain amino acids, an increase in circulating branched-chain amino acid concentration might delay the onset of fatigue (Davis, 2000).…”

Section: Central Nervous System Effectsmentioning

confidence: 99%

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The athlete’s diet: nutritional goals and dietary strategies

Maughan

2002

Proc. Nutr. Soc.

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When talented, motivated and highly trained athletes meet for competition the margin between victory and defeat is usually small. When everything else is equal, nutrition can make the difference between winning and losing. Although the primary concern of many athletes is to supplement the diet with protein, vitamins and minerals, and a range of more exotic compounds, key dietary issues are often neglected. Athletes must establish their nutritional goals, and must also be able to translate them into dietary strategies that will meet these goals. Athletes are often concerned with dietary manipulations in the period around competition, but the main role of nutrition may be to support consistent intensive training which will lead to improved performance. Meeting energy demand and maintaining body mass and body fat at appropriate levels are key goals. An adequate intake of carbohydrate is crucial for maintaining muscle glycogen stores during hard training, but the types of food and the timing of intake are also important. Protein ingestion may stimulate muscle protein synthesis in the post-exercise period, promoting the process of adaptation in the muscles. Restoration of fluid and electrolyte balance after exercise is essential. If energy intake is high and a varied diet is consumed, supplementation of the diet with vitamins and minerals is not warranted, unless a specific deficiency is identified. Specific strategies before competition may be necessary, but this requirement depends on the demands of the sport. Generally, it is important to ensure high pre-competition glycogen stores and to maintain fluid balance. There is limited evidence to support the use of dietary supplements, but some, including perhaps creatine and caffeine, may be beneficial.

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Section: Central Nervous System Effectsmentioning

confidence: 99%

Section: Central Nervous System Effectsmentioning

confidence: 99%

The athlete’s diet: nutritional goals and dietary strategies

Maughan

2002

Proc. Nutr. Soc.

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“…It has been proposed that fatigue during prolonged exercise may have a central as well as a physical basis. It has been suggested that an increased concentration of brain serotonin (5-hydroxytryptamine) may contribute to CNS (central nervous system) fatigue during prolonged exercise (the original central fatigue hypothesis; [55]). Brain serotonin synthesis is dependent on the availability of its amino acid precursor, free tryptophan (termed f-TRP) and the activity of the rate-limiting enzyme tryptophan hydroxylase [56].…”

Section: Ingestion Of Bcaasmentioning

confidence: 99%

“…In the brain, tryptophan is converted into serotonin, and an increase in this neurotransmitter infl uences behaviour, such as sleep and mood, which may affect perceived exertion during exercise. Thus any increase in the plasma fatty acid level [tryptophan, like fatty acids, is bound to albumin in the plasma, so increasing NEFA (non-esterifi ed fatty acid) displaces tryptophan from albumin increasing its availability for uptake] or decrease in plasma concentration of BCAAs results in an increased entry of tryptophan into the brain, and thus central fatigue [55] (see Figure 5).…”

Section: Ingestion Of Bcaasmentioning

confidence: 99%

Legal nutritional supplements during a sporting event

Nicholas

2008

Essays in Biochemistry

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Nutrition significantly influences sports performance; however, the efficacy of any nutritional supplement or strategy should be carefully considered in relation to the event and the sex, training and nutritional status of the participant. The causes of fatigue, mechanism of action, safety and legality of the supplement, together with the scientific evidence from studies with an appropriate experimental design, should all be taken into account before incorporating into the training and/or competition diet. The efficacy of ingesting nutritional supplements immediately before and/or during endurance exercise (duration 45-180 min) is reviewed in this chapter. The ingestion of CES (carbohydrate-electrolyte solutions) have been shown to improve both exercise capacity and performance, either due to the maintenance of euglycaemia throughout exercise or the sparing of muscle glycogen early on in exercise. The addition of caffeine to CES may improve endurance performance as a consequence of a reduced perception of effort. Research suggests that the addition of protein to CES may only be effective when a suboptimal amount of CHO (carbohydrate) is ingested during exercise (<60 g of CHO.h(-1)); however, recovery of performance may be enhanced due to a reduction in subsequent muscle soreness and the promotion of muscle protein synthesis after exercise. The findings from studies investigating the effects of ingesting MCTs (medium-chain triacylglycerols) and BCAAs (branched-chain amino acids), either on their own or in combination with CES, on endurance performance have been equivocal and therefore would not be recommended. Any nutritional strategy should be practised in training before being used during a competition.

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“…due to prolonged exercise or environmental stress). When choline is available in near-physiologic concentrations, choline supplementation increases acetylcholine release from nerves, enhancing neurotransmission C Wurtman (1994), Zeisel (1994) Tryptophan The brain neurotransmitter serotonin, which theoretically is involved in central fatigue, may be modulated by diet or plasma levels of its precursor tryptophan, an amino acid; evidence for this effect is limited E Maughan (2002), Newsholme and Castell (2000), Wilson and Maughan (1992) Vitamin C, vitamin E, selenium, and b-carotene…”

mentioning

confidence: 98%

Nutritional strategies for football: Counteracting heat, cold, high altitude, and jet lag

Armstrong

2006

Journal of Sports Sciences

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Environmental factors often influence the physical and mental performance of football players. Heat, cold, high altitude, and travel across time zones (i.e. leading to jet lag) act as stressors that alter normal physiological function, homeostasis, metabolism, and whole-body nutrient balance. Rather than accepting performance decrements as inevitable, well-informed coaches and players should plan strategies for training and competition that offset environmental challenges. Considering the strength of scientific evidence, this paper reviews recommendations regarding nutritional interventions that purportedly counterbalance dehydration, hyperthermia, hypothermia, hypoxia, acute or chronic substrate deficiencies, sleep loss, and desynchronization of internal biological clocks.

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Amino Acids, Fatigue and Immunodepression in Exercise

Cited by 8 publications

References 78 publications

The athlete’s diet: nutritional goals and dietary strategies

The athlete’s diet: nutritional goals and dietary strategies

Legal nutritional supplements during a sporting event

Nutritional strategies for football: Counteracting heat, cold, high altitude, and jet lag

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