Nutrition and Metabolic Factors
Michael H. Stone, Timothy J. Suchomel, W. Guy Hornsby, John P. Wagle, Aaron J. Cunanan in Strength and Conditioning in Sports, 2023
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
Robert Fried, Richard M. Carlton in Flaxseed, 2023
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.
Analysis Update—Full Spectrum Cannabis
Betty Wedman-St Louis in Cannabis as Medicine, 2019
There are 500 naturally occurring amino acids in nature, but only 20 appear in the genetic code. Of those 20 amino acids, 9 are considered essential amino acids, meaning they cannot be produced by the body and must come from the diet. The nine essential amino acids are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. Amino acids contain functional groups consisting of an amine (–NH2) and a carboxyl (–COOH) group as well as a side chain (R group). Peptides form when the amine group of one amino acid combines with the carboxyl group of another amino acid. Amino acids are called peptides when a molecule contains a chain of 2–50 amino acids linked together. To be more specific, chains of 20–50 amino acids are referred to as polypeptides; beyond 50 amino acids, the peptides chains are referred to as proteins. Amino acids have been called the building blocks of life. Lacking enough of an essential amino acid will handicap the synthesis of proteins. In the opposite direction, when one consumes proteins, they are broken down in the body to form beneficial amino acids.
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.
Optimal Protein Intake during Weight Loss Interventions in Older Adults with Obesity
Published in Journal of Nutrition in Gerontology and Geriatrics, 2019
Whey protein, given as a supplement in addition to food at doses of 20–25 g once or twice daily, has been shown to independently improve protein synthesis in older muscle, though more studies are needed to confirm this (42, 44, 46, 71–75). Mojtahedi et al. provided a whey-based supplement twice daily and observed a higher percentage of muscle preservation relative to weight loss, with better functional performance (64). Murphy et al. noted improved muscle protein synthesis with a whey protein supplement in the am (63). Specifically, essential amino acids and the branched chain amino acid leucine may be of importance. Coker’s group provided a whey supplement enriched with additional essential amino acids, and observed better muscle protein synthesis (65). Other studies have shown similar effects, perhaps indicating a preference in aging muscle for these amino acids (43, 76, 77). Whey supplementation has not been shown to be effective in other trials—perhaps because the quality of supplements varies greatly (78, 79). Quality control is lacking, as supplements fall outside the reach of the United States Food and Drug Administration (80). If indicated, it is paramount to choose a supplement that has been independently tested and verified for quality and safety by bodies such as the United States Pharmacopeia or the National Sports Foundation.
Dose, timing, and source of protein intake of young people with spastic cerebral palsy
Published in Disability and Rehabilitation, 2020
Ieke Anker–van der Wel, Ana R. P. Smorenburg, Nicole M. de Roos, Olaf Verschuren
In addition to dose and timing, the quality of the protein source is important. Daily protein intake can be derived from various protein-containing food sources. In the existing literature, information on the specific food sources that contribute to total protein intake in children with CP is lacking. Quality of the protein source is determined by the (essential) amino acid composition, digestibility and bioavailability of amino acids (absorption kinetics) [28,29]. Proteins from animal sources are considered to be high quality as they contain all essential amino acids and have a digestibility and absorption of 90–99%. Proteins from plant-based sources, on the other hand, are less digestible, varying from 70–90% and do not contain all essential amino acids [28,29]. Our findings revealed that more than 40% of daily dietary protein intake in children with CP in this study originates from plant-based sources. It is recommended that a diet contains a variety of protein sources because the variation will automatically lead to a sufficient intake of all (non-)essential amino acids [24]. As the participants in the current study consumed protein from both plant- and animal-based sources it is likely that their diet provides all essential amino acids.