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Nutrition and Metabolic Factors
Published in Michael H. Stone, Timothy J. Suchomel, W. Guy Hornsby, John P. Wagle, Aaron J. Cunanan, Strength and Conditioning in Sports, 2023
Michael H. Stone, Timothy J. Suchomel, W. Guy Hornsby, John P. Wagle, Aaron J. Cunanan
The biological value (BV) of a protein is a measure of the absorption and utilization of a protein. If the BV of a protein is higher, more nitrogen is absorbed, used, and retained, making proteins with higher BV those that can better promote greater levels of tissue remodeling and muscle gains. Protein synthesis (anabolism) in humans requires approximately 22 distinct amino acids, nine of which are classified as essential amino acids (EAA) in adults. Essential amino acids are defined as those that cannot be synthesized within the human body and must instead be consumed within an individual’s diet (Table 4.3). In contrast, nonessential amino acids can be synthesized from other substances, such as carbohydrate, assuming an adequate nitrogen source (such as other amino acids) has been made available. Regarding various food sources that supply EAA, some dietary proteins have been classified as either complete or incomplete proteins. Complete proteins are those that contain all the EAA needed for the synthesis of human tissue and have a high BV. Many of these proteins are typically found in animal sources and products such as red meat, dairy products, eggs, fish, and fowl. In contrast, incomplete proteins are those that contain very low amounts of one or more EAA. These proteins generally originate from plant sources and include nuts, grains, legumes, and seeds. However, it should be noted that the quantity of protein available in some plant sources (e.g., beans) is relatively high and may partially offset the lower BV that is typical of incomplete proteins.
Flaxseed, a Functional Food—Constituents and Their Health Benefits
Published in Robert Fried, Richard M. Carlton, Flaxseed, 2023
Robert Fried, Richard M. Carlton
Amino acids are classified into three groups: Essential amino acids cannot be made by the body, and so they must come from food. There are nine essential amino acids: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine.Nonessential amino acids can be produced by the body. These are alanine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, pro-line, serine and tyrosine.Conditional amino acids are usually not essential, except in times of illness and stress. These are arginine, cysteine, glutamine, tyrosine, glycine, ornithine, proline and serine. One does not need essential and nonessential amino acids at every meal, but getting a balance of them over the whole day is important. (3) Flax protein is not considered to be a complete protein due to the presence of the limiting amino acid lysine.
Molecular adaptation to resistance exercise
Published in Adam P. Sharples, James P. Morton, Henning Wackerhage, Molecular Exercise Physiology, 2022
Even though myofibrillar protein synthesis increases following a single bout of resistance exercise, if training is performed in the fasted state, the increase in muscle protein degradation will be greater than the increase in protein synthesis, resulting in a negative protein balance (Figure 8.3). Protein balance only becomes positive, and thus muscle fibre hypertrophy only occurs, in the presence of sufficient essential amino acids, such as following a meal (17). Amino acid intake and the molecular regulation of protein synthesis after exercise are covered in detail in Chapter 10. Briefly, consuming essential amino acids not only increases muscle protein synthesis, but also decreases protein breakdown following resistance exercise, suggesting that the increase in protein breakdown following resistance exercise in the fasted state occurs in order to supply essential amino acids for protein synthesis. Since essential amino acids only come from the diet or stored protein, they must be supplied by breaking down existing protein if insufficient protein has been ingested. Therefore, following resistance exercise in a fasted state, more protein must be degraded to produce the precise amino acid mix necessary to synthesize novel proteins. With training, muscles become better at recycling amino acids resulting in better overall protein balance in the fasted state (18).
Oral Nutritional Supplementation in Cancer Patients Who Were Receiving Chemo/Chemoradiation Therapy: A Multicenter, Randomized Phase II Study
Published in Nutrition and Cancer, 2021
Adilson Aparecido Faccio, Cecilia Helena Peinado de Sampaio Mattos, Evandro Airton Sordi dos Santos, Natael Ribeiro Malta Neto, Raquel Pedro Moreira, Hellin dos Santos, Ana Paula Monnerat Celes
Moreover, data about FFM did not significantly differ between the S arm and C arm. One hypothesis is that the patients’ exposure time to the supplement might not have been enough to cause significant changes. In the literature, data regarding this topic are controversial. Some studies have shown an increase in the FFM of oncologic patients receiving hypercaloric and/or hyperproteic supplements, as mentioned previously. Meanwhile, others do not. In a randomized trial of nutritional supplement with specific components in oncologic patients, Fearon et al. have shown that weight and lean body mass loss can be inhibited with 8 weeks of oral supplementation, as observed in this study, and changes in lean body mass are based on the amount of supplementation ingested in terms of energy and protein (10). The effect of the distribution of protein in meals during the day has also been discussed recently. According to the study of Volpi et al. (27), to observe the effect on muscle mass, the daily protein dose must be distributed in three meals with intakes of 25–30 g, with at least 15 g corresponding to essential amino acids, which are primarily responsible for protein synthesis. Wilkinson et al. have shown an increase in muscle protein synthesis by 110% after a dose of 3.42 g of leucine was administered orally, as assessed directly in the myofibril (28). In addition, the specialized supplement guaranteed an average leucine dose of 3.93 g/day in this group of patients.
Probiotic-directed modulation of gut microbiota is basal microbiome dependent
Published in Gut Microbes, 2020
Qiangchuan Hou, Feiyan Zhao, Wenjun Liu, Ruirui Lv, Wei Wei Thwe Khine, Jia Han, Zhihong Sun, Yuan-Kun Lee, Heping Zhang
Functional analysis showed that there were significant differences between the two enterotypes in many metabolic modules. For example, three modules related to lipopolysaccharide metabolism were significantly more abundant in PF enterotypes than FB enterotypes, while many pathways related to human essential amino acid synthesis were significantly higher in FB enterotypes than PF enterotypes. Lipopolysaccharides are components of the cell membranes of gram-negative bacteria, and gut microbiota-derived lipopolysaccharides and systemic endotoxemia are involved in the onset and progression of atherosclerosis, inflammatory bowel disease, obesity and related metabolic diseases, and nonalcoholic steatohepatitis.52–54 Essential amino acids are those amino acids that cannot be synthesized by the human body, or cannot be synthesized at a speed that meets requirements and must be provided from external sources. A lack of essential amino acids leads to a series of problems including metabolic disorders and a decline in immune resistance.55 Considering that the biosynthesis pathway for lipopolysaccharide was enriched in PF enterotypes and various modules related to the synthesis of essential amino acids were enriched in FB enterotypes, we speculate that the composition of gut microbiota of FB enterotypes may be more beneficial to the health of adults. After LCZ consumption, the enterotype of many adults changed from PF to FB with a significant decrease in abundance of the lipopolysaccharide biosynthesis module in both enterotypes confirms the probiotic effect of LCZ.
Birth weight related essential, non-essential and conditionally essential amino acid blood concentrations in 12,000 breastfed full-term infants perinatally
Published in Scandinavian Journal of Clinical and Laboratory Investigation, 2020
Penelope D. Manta-Vogli, Kleopatra H. Schulpis, Yannis L. Loukas, Yannis Dotsikas
Based on dietary needs for growth or nitrogen balance, amino acids (AAs) have traditionally been classified as nutritionally essential or nonessential [2]. Essential AAs (EAAs; Table 1) are those whose carbon skeletons cannot be synthesized or those that are inadequately synthesized de novo by the body, relative to needs and which must be provided from the diet to meet requirements. Except for lysine and threonine, metabolic needs for EAAs can be also covered through the intake of the corresponding keto acids, as they can be transaminated in the body to yield the respective amino acid [3]. Non-essential AAs (NEAAs; Table 1) are those AAs that can be synthesized de novo in adequate amounts by the body from carbon skeletons, derived from lipid and carbohydrate sources or from transformations that involve EAAs. NΕΑΑs and their precursors are: glutamic acid (α-ketoglutaric acid), aspartic acid (oxaloacetic acid), serine (3-phosphoglyceric acid), glycine (serine), tyrosine (phenylalanine), proline (glutamic acid), alanine (pyruvic acid), cysteine (methionine and serine), arginine (glutamate-γ-semialdehyde), glutamine (glutamic acid), and asparagine (aspartic acid). From a nutritional, as well as metabolic view, all the 20 amino acids must be present in sufficient quantities to support growth and individuals’ health. The absence of any essential amino acid leads to the cessation of protein synthesis, catabolism of unused amino acids, increased loss of nitrogen in urine, and reduced growth [3].