Long-term leucine supplementation does not increase muscle mass or strength in healthy elderly men

Verhoeven, Suzanne; Vanschoonbeek, Kristof; Verdijk, Lex B.; Koopman, René; Wodzig, Will K. W. H.; Dendale, Paul; Loon, Luc J. C. van

doi:10.3945/ajcn.2008.26668

Cited by 241 publications

(251 citation statements)

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“…L‐Leu did not significantly stimulate protein synthesis and mTOR phosphorylation. These results are in agreement with those that demonstrate that supplementation with L‐Leu failed to elicit an additional response in rats12 or in well‐nourished healthy elderly men 37. Interestingly, our results showed that HMB was a significantly more active effector than L‐Leu under these conditions.…”

Section: Discussionsupporting

confidence: 93%

“…showed that while administration of low doses of L‐Leu‐stimulated protein synthesis in muscle in food‐deprived mature rats, further supplementation with L‐Leu failed to elicit an additional response. Verhoeven et al 37. also reported that long‐term supplementation of L‐Leu in well‐nourished healthy elderly men did not improve muscular mass and strength.…”

Section: Discussionmentioning

confidence: 98%

“…L‐Leu stimulates protein synthesis in muscle cells through at least two distinct mechanisms: by stimulation of mRNA translation initiation machinery13, 35 and by activation of intracellular signalling pathways linked to mTOR 6, 36, 37. The positive effects of L‐Leu supplementation on protein synthesis have been widely studied in situations where the subjects were either in deficient or fasting conditions,8, 11, 12, 13, 14, 15 and therefore under a catabolic stimulus.…”

Section: Discussionmentioning

confidence: 99%

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Conversion of leucine to β-hydroxy-β-methylbutyrate by α-keto isocaproate dioxygenase is required for a potent stimulation of protein synthesis in L6 rat myotubes

Girón

Rienda

Salto

et al. 2015

Journal of Cachexia, Sarcopenia and Muscle

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BackgroundL‐Leu and its metabolite β‐hydroxy‐β‐methylbutyrate (HMB) stimulate muscle protein synthesis enhancing the phosphorylation of proteins that regulate anabolic signalling pathways. Alterations in these pathways are observed in many catabolic diseases, and HMB and L‐Leu have proven their anabolic effects in in vivo and in vitro models. The aim of this study was to compare the anabolic effects of L‐Leu and HMB in myotubes grown in the absence of any catabolic stimuli.MethodsStudies were conducted in vitro using rat L6 myotubes under normal growth conditions (non‐involving L‐Leu‐deprived conditions). Protein synthesis and mechanistic target of rapamycin signalling pathway were determined.ResultsOnly HMB was able to increase protein synthesis through a mechanism that involves the phosphorylation of the mechanistic target of rapamycin as well as its downstream elements, pS6 kinase, 4E binding protein‐1, and eIF4E. HMB was significantly more effective than L‐Leu in promoting these effects through an activation of protein kinase B/Akt. Because the conversion of L‐Leu to HMB is limited in muscle, L6 cells were transfected with a plasmid that codes for α‐keto isocaproate dioxygenase, the key enzyme involved in the catabolic conversion of α‐keto isocaproate into HMB. In these transfected cells, L‐Leu was able to promote protein synthesis and mechanistic target of rapamycin regulated pathway activation equally to HMB. Additionally, these effects of leucine were reverted to a normal state by mesotrione, a specific inhibitor of α‐keto isocaproate dioxygenase.ConclusionOur results suggest that HMB is an active L‐Leu metabolite able to maximize protein synthesis in skeletal muscle under conditions, in which no amino acid deprivation occurred. It may be proposed that supplementation with HMB may be very useful to stimulate protein synthesis in wasting conditions associated with chronic diseases, such as cancer or chronic heart failure.

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Section: Discussionsupporting

confidence: 93%

Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

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Conversion of leucine to β-hydroxy-β-methylbutyrate by α-keto isocaproate dioxygenase is required for a potent stimulation of protein synthesis in L6 rat myotubes

Girón

Rienda

Salto

et al. 2015

Journal of Cachexia, Sarcopenia and Muscle

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“…3,4 -5 g de Leucina) em conjunto com outras proteínas (ex: mix de proteínas) 9 ou na forma isolada 15 , e demonstraram aumento da TSP miofibrilar. Além disso, doses superiores a 4 g (ex: 7,5 g/dia) têm sido bem toleradas, em estudos em um longo prazo 16 .…”

Section: Suplementaçãounclassified

Efeitos da Suplementação de Leucina Associada ao Treinamento Resistido Sobre a Força Muscular em Sujeitos Jovens

et al. 2017

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A proposta do presente estudo foi avaliar os efeitos da suplementação de leucina associada ao treinamento resistido (TR) de alta intensidade sobre a força muscular em sujeitos jovens não treinados. Para tanto, 24 indivíduos jovens não treinados, de ambos os sexos, foram divididos em dois grupos (N = 12/grupo): Leucina (4g de leucina + 8g dextrose) e Placebo (12g dextrose). Ambos os grupos foram submetidos a um programa de TR de alta intensidade (3 séries de 12 repetições máximas; 2x/semana) com duração de 6 semanas, e consumiram seus respectivos suplementos imediatamente após cada sessão de treino. As sessões de treino consistiram na realização dos exercícios de leg press e cadeira extensora, a fim de maximizar o recrutamento do músculo quadríceps. Ambos os grupos foram submetidos ao teste de uma repetição máxima (1RM) nos exercícios de leg press e cadeira extensora, nos momentos pré e pós-treinamento. Ao término do treinamento, houve um significante (P < 0,05) aumento do 1RM em ambos os exercícios, mas nenhuma diferença foi observada entre os grupos. Além disso, a progressão da carga de treino foi similar (P > 0,05) entre os grupos, após 4 e 6 semanas de treinamento. Estes resultados indicam que a suplementação de uma baixa dose semanal de leucina (4g/dia; 2x/semana) associada ao TR em curto prazo não promove efeitos adicionais sobre a força muscular em indivíduos jovens não treinados.Palavras-chave: Músculo Esquelético. Suplementação Alimentar. Leucina. AbstractThe purpose of the study herein was to examine the leucine supplementation effects associated with high-intensity resistance training (RT) on muscle strength in young untrained subjects. Twenty-four young untrained subjects fromboth sexes were divided into two groups (N = 12/ group) IntroduçãoO aumento da massa muscular induzido pelo treinamento resistido (TR) é principalmente atribuído a uma ação coordenada de vias intracelulares, que controlam a relação entre síntese (anabolismo) e degradação (catabolismo) de proteínas contráteis no tecido muscular [1][2][3] . A via de sinalização da proteína alvo da rapamicina em mamíferos (mammalian target of rapamycin [mTOR]) tem sido descrita como uma das principais responsáveis pelo aumento da relação entre a taxa de síntese e degradação protéica miofibrilar em resposta ao exercício resistido 4 , e consequente aumento da massa muscular.A mTOR pode ser ativada por meio de estímulos mecânicos (ex: TR) e nutricionais (ex: consumo de proteínas) que convergem na fibra muscular 4 . Por exemplo, os aminoácidos essenciais (essential amino acid [EAAs]) (em particular a leucina) têm sido descritos como potenciais estimuladores da síntese protéica, por meio da ativação da via mTOR 4 . Prévios estudos relatam que a administração de leucina (1,35 g/kg de peso corporal) pode aumentar a taxa de síntese protéica (TSP) e o nível de estimulação da via mTOR no músculo esquelético de ratos desprovidos de alimento 5 . Adicionalmente, tem sido reportado um aumento da TSP em homens jovens, que consumiram uma bebida contendo EAAs enri...

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“…As a dietary supplement, leucine has been found to slow the degradation of muscle tissue by increasing the synthesis of muscle proteins in aged rats (Combaret et al, 2005). However, the supplementation of leucine with long-term didn't increase muscle mass or strength in healthy elderly men (Verhoeven et al, 2009). Until now, the dietary supplemental of leucine has not be associated the prime reason for muscular growth or optimal maintenance for the entire population.…”

Section: Compositions Of Essential Amino Acidsmentioning

confidence: 99%

Comparative Analysis of Mineral Elements and Essential Amino Acids Compositions in <i>Juglans sigillata<i> and <i>J. regia<i> Walnuts Kernels

Mei-zhi¹,

Wang²,

Wang³

et al. 2014

Not Bot Hort Agrobot Cluj

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Walnut kernel is famous for its high nutritional and economic values. The kernel is usually considered to be a good source of minerals and essential amino acids. In this paper, mineral elements (calcium, magnesium, iron, manganese, copper, and zinc) and essential amino acids (phenylalanine, valine, threonine, isoleucine, leucine, methionine, and lysine) compositions of kernels from 11 kinds of walnuts (Juglans sigillata) and 17 kinds of walnuts (Juglans regia) originated from China were determined by ICP-MS and HPLC, respectively. The order of nutritive mineral elements depending on their content (mg/100g) of samples was Mg> Ca> Zn> Mn> Fe> Cu in J. regia, while the order in J. sigillata was Mg> Ca> Mn> Fe > Zn > Cu. For essential amino acids, the order depending on the content (mg/g) of the essential amino acids in J. regia samples was leucine> isoleucine> valine> phenylalanine> lysine> threonine> methionine, while the order in J. sigillata was leucine> isoleucine> lysine> phenylalanine> valine> threonine> methionine. The kernels of walnuts (J. regia and J. regia) are good sources of health foods and dietary supplements. 'Y029' in Juglans sigillata and 'XJ004' in Juglans regia provided the best profiles of mineral elements and essential amino acids in comparison to others.

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Long-term leucine supplementation does not increase muscle mass or strength in healthy elderly men

Abstract: Long-term leucine supplementation (7.5 g/d) does not augment skeletal muscle mass or strength and does not improve glycemic control or the blood lipid profile in healthy elderly men. This trial was registered at clinicaltrials.gov as NCT00807508.

Cited by 241 publications

References 38 publications

Conversion of leucine to β-hydroxy-β-methylbutyrate by α-keto isocaproate dioxygenase is required for a potent stimulation of protein synthesis in L6 rat myotubes

Conversion of leucine to β-hydroxy-β-methylbutyrate by α-keto isocaproate dioxygenase is required for a potent stimulation of protein synthesis in L6 rat myotubes

Efeitos da Suplementação de Leucina Associada ao Treinamento Resistido Sobre a Força Muscular em Sujeitos Jovens

Comparative Analysis of Mineral Elements and Essential Amino Acids Compositions in <i>Juglans sigillata<i> and <i>J. regia<i> Walnuts Kernels

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