Increased Dietary Protein Modifies Glucose and Insulin Homeostasis in Adult Women during Weight Loss

Layman, Donald K.; Shiue, Harn; Sather, Carl; Erickson, Donna J.; Baum, Joseph D.

doi:10.1093/jn/133.2.405

Cited by 164 publications

(139 citation statements)

References 30 publications

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“…This study also showed higher concentration of hepatic protein and RNA in the gastrocnemius muscle of the supplemented group. These results indicated that leucine supplementation in rats submitted to food restriction stimulated body fat loss, improved hepatic protein status and protein synthesis ability in muscle.The authors did not consider the findings related to body composition striking, considering that some human studies have already evidenced that an increase in BCAA consumption can improve the body loss process (Layman et al, 2003a., Mourier et al, 1997Layman, 2003;Layman et al, 2003b). Furthermore, studies comparing diets with different protein concentrations demonstrated significant changes in body composition in groups on a high-protein diet, especially by reducing fat mass and lowering loss of lean body mass.…”

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confidence: 99%

Protein synthesis regulation by leucine

Vianna

Teodoro

Leal

et al. 2010

Braz. J. Pharm. Sci.

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In vivo and in vitro studies have demonstrated that high protein diets affect both protein synthesis and regulation of several cellular processes. The role of amino acids as substrate for protein synthesis has been established in the literature. However, the mechanism by which these amino acids modulate transcription and regulate the mRNA translation via mTOR-dependent signaling pathway has yet to be fully determined. It has been verified that mTOR is a protein responsible for activating a cascade of biochemical intracellular events which result in the activation of the protein translation process. Of the aminoacids, leucine is the most effective in stimulating protein synthesis and reducing proteolysis. Therefore, it promotes a positive nitrogen balance, possibly by favoring the activation of this protein. This amino acid also directly and indirectly stimulates the synthesis and secretion of insulin, enhancing its anabolic cellular effects. Therefore, this review aimed to identify the role of leucine in protein synthesis modulation and to discuss the metabolic aspects related to this aminoacid. Uniterms:Leucine. Protein synthesis. Transcription Factors. mTOR. Translation Protein.Estudos in vivo e in vitro verificaram que dietas hiperprotéicas influenciam a síntese protéica e regulam vários processos celulares. O papel dos aminoácidos como substrato para a síntese de proteínas já está bem evidenciado na literatura, porém as formas como esses aminoácidos modulam a etapa da transcrição e regulam a tradução do RNAm, pela via de sinalização dependente da mTOR, ainda não estão totalmente esclarecidas. Tem-se verificado que a mTOR é uma proteína responsável por ativar uma cascata de eventos bioquímicos intracelulares que culminam na ativação do processo de tradução protéica. Dentre todos os aminoácidos, a leucina é a mais eficaz em estimular a síntese protéica, reduzir a proteólise e, portanto, favorecer o balanço nitrogenado positivo, possivelmente por favorecer a ativação desta proteína. Além disso, este aminoácido estimula direta e indiretamente a síntese e a secreção de insulina, e, assim, aumenta as propriedades anabólicas celulares. Nesse sentido, a presente revisão tem como objetivo identificar o papel da leucina na modulação da síntese protéica e abordar aspectos metabólicos relacionados a este aminoácido.Unitermos: Leucina. Síntese protéica. Fator de transcrição. mTOR. Tradução de proteínas. INTRODUCTIONProtein synthesis in tissue is rapidly stimulated after nutrient consumption. Insulin and aminoacids stimulate protein anabolism, acting in a posterior step of gene transcription, i.e., on protein translation. However, the mechanism by which the aminoacids stimulate protein translation has yet to be fully determined (Proud, 2002).Some studies have verified that high-protein diets stimulate protein synthesis. Some of the benefits promoted by this diet on body composition can be attributed to high consumption of branched-chain aminoacids (BCAA), which include the aminoacids leucine, valine and isoleucine (Donato...

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mentioning

confidence: 99%

Protein synthesis regulation by leucine

Vianna

Teodoro

Leal

et al. 2010

Braz. J. Pharm. Sci.

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“…Better outcomes with HP diets compared with HC diets in ad libitum setting may be related to the greater acute satiety associated with protein compared with glucose or fat [79][80][81]. HP diets have also been shown to produce lower fasting and postprandial insulin levels [50,[82][83][84][85].…”

Section: Moderate Carbohydrate High-protein Low-fat Diets (~40% Carmentioning

confidence: 99%

“…While most studies found that HP and HC diets had no differential effects on total and LDL cholesterol levels, some have shown that either HP or HC diets produced better outcomes [67,73,74,86,87]. HP diets were also found to result in higher fasting glucose levels compared with HC diets during weight loss [82][83][84]87]. Replacing carbohydrate with protein resulted in an inconsistent effect on postprandial glucose.…”

Section: Moderate Carbohydrate High-protein Low-fat Diets (~40% Carmentioning

confidence: 99%

“…Replacing carbohydrate with protein resulted in an inconsistent effect on postprandial glucose. Studies have shown that HP diets had greater decrease in postprandial glucose during weight maintenance but not during weight loss [63,[83][84][85]. Studies that investigated the combination of LGI and HP (LGIHP) diet in non-PCOS women have reported better body weight, triglyceride, HDL cholesterol, fasting insulin and postprandial insulin and glucose outcomes compared with HC diet [67,81].…”

Section: Moderate Carbohydrate High-protein Low-fat Diets (~40% Carmentioning

confidence: 99%

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Obesity Management in Women with Polycystic Ovary Syndrome

Lim

Clifton

Noakes

et al. 2007

Womens Health (Lond Engl)

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Obesity and insulin resistance play an important role in initiating or maintaining ill health in polycystic ovary syndrome (PCOS). This implies that treatment that reduces body weight and insulin resistance would alleviate the symptoms of PCOS. Lifestyle modification has been found to be effective in restoring reproductive function in up to 80% of individuals who achieve at least 5% weight loss. However, long-term weight maintenance is a challenge. This article provides a review of reduced glycemic load diets, including low glycemic index, very low carbohydrate, high-protein and high monounsaturated fat diets, on metabolic and reproductive health in PCOS and non-PCOS populations. Dietary trials in non-PCOS women suggest that higher-protein, reduced glycemic load diets were probably more beneficial than the conventional low-fat, high-carbohydrate diet but further studies are required to confirm this in PCOS women. Similarly, the optimal exercise regime for PCOS women remains to be investigated.Obesity & polycystic ovary syndrome Polycystic ovary syndrome (PCOS) is one of the most common endocrine conditions that affects obese and nonobese women during reproductive age. Its symptoms include irregular menses, infertility, acne and hirsutism (excessive hair growth). During pregnancy, PCOS probably also increases the risk of early miscarriages and complications such as pre-eclampsia and gestational diabetes [1]. As a result of these physical manifestations, women with PCOS tend to have poorer psychological health and lower quality of life [2]. Increasing evidence also suggests that women with PCOS may be at greater risk of developing metabolic diseases such as type 2 diabetes and cardiovascular disease in the long term [3,4].Owing to its heterogeneity, the diagnostic criteria for PCOS have been a contentious issue among experts. The 1990 National Institutes of Health (NIH) meeting defined PCOS as the coexistence of chronic anovulation and hyperandrogenism, with the exclusion of other diseases such as thyroid disorder, hyperprolactinemia, congenital adrenal hyperplasia, androgensecreting tumors and Cushing syndrome [5]. In 2003, this definition was broadened to include women with either hyperandrogenism or anovulation in addition to having polycystic ovaries. Using the previous NIH definition, the prevalence of PCOS was estimated to be 5-8% of women of reproductive age [6][7][8][9]. This number is estimated to increase by 65% using the latest revised diagnostic criteria [10]. Obesity & fat distribution in PCOS womenIt is estimated that 30-60% of women with PCOS are overweight or obese in the Western world [7,[11][12][13][14]. Some suggest that the prevalence of obesity is higher in PCOS women compared with healthy controls [7,15,16]. In a study involving 3094 women, Glueck and colleagues found that approximately 73-78% of women with PCOS aged between 20 and 41 years were obese (body mass index [BMI]>30 kg/m 2 ) compared with 7-14% in the general population [16]. In addition to being potentially predisposed to obesity,...

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“…During the last decade the notion that athletes as well generally active population require greater protein intake than the currently RDA recommendation of 0.8 g/kg of body weight per day in healthy adults has become well accepted [1,2]. In addition, high protein diets have also become quite popular in general population as part of many weight reduction programs [3,4]. Differences in protein requirements for different types of athletes (i.e., endurance, strength/power) and non-athletes are well documented [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Effectiveness of Whey Protein Supplement in Resistance Trained Individuals

Naclerio

Alkhatib

Jiménez

2013

J Sports Med Doping Stud

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Athletes and recreationally resistance-trained individuals often use protein supplements in an attempt to maximize their training gains and performance. Because of the high bioavailability and solubility and its higher proportion of essential amino acids including Leucine, whey protein extract has been proposed as the best optimal form of protein for strength and power athletes. The objective of this review is to examine the current evidence for the efficacy of whey protein containing supplements to optimize strength training adaptation and outcomes for regular resistance training practitioners.A limited numbers of studies have reported positive effects of whey protein containing supplements (including those with carbohydrate and creatine) for optimizing the anabolic responses and adaptations process in resistancetrained individuals.In order to promote a more anabolic environment and maximize muscle protein synthesis along the day, an eating pattern behavior involving frequents meals (every 3 to 5 h) containing 17 to 20 g of high quality protein (200 to 250 mg/ kg) providing 8 to 10 g of EAA (90 to 110 mg/kg) and about 2 g of Leucine (20 to 25 mg/kg) have been recommended. Special attention should be given to the periworkout hours where the ingestion of whey proteins combined with carbohydrates, creatine monohydrate (0.1 g/kg/d) and other proteins sources such as casein before, during and after workout have been shown to improve training adaptations and enhance the recovery process. However, when considering that the training conditions (workout volume, organization, number of exercises) used in the available studies are substantially different than what athletes actually perform. Optimal whey protein supplementation protocols need to specifically be based on the regular resistance training workout organization and would probably need to consider other doses and timing strategies than what is currently recommended.

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Increased Dietary Protein Modifies Glucose and Insulin Homeostasis in Adult Women during Weight Loss

Cited by 164 publications

References 30 publications

Protein synthesis regulation by leucine

Protein synthesis regulation by leucine

Obesity Management in Women with Polycystic Ovary Syndrome

Effectiveness of Whey Protein Supplement in Resistance Trained Individuals

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