Amino acid profiles explained in detail. How many do you need and which ones are essential?
Agil Nature
Amino acids are the elementary building blocks ( monomers ) Proteins are the fundamental building blocks of all living cells. They fulfill a multitude of physiological functions – from the structural integrity of muscle tissue to the synthesis of enzymes and hormones to the modulation of immunological processes. They are precursors of neurotransmitters, contribute to the regulation of acid-base balance, and serve as substrates in countless metabolic pathways. Connective tissue, skin, hair, and nails also consist largely of protein-structured compounds, the quality and functionality of which directly depend on an adequate supply of all necessary amino acids. For precise, evidence-based nutritional planning, it is therefore essential to know the composition and ratio of amino acids in different food sources – the so-called amino acid profile.
Classification of proteinogenic amino acids
The human metabolism uses 20 (21 with selenocysteine) proteinogenic amino acids for the construction of the body's own proteins. These can be divided into three main groups according to their endogenous synthesis capacity:
Essential amino acids (EAA): Cannot be synthesized by the body and must be supplied entirely through food.
Non- essential amino acids (NEAA): Can be formed in the organism from other precursors.
Semi- essential amino acids: Under special physiological or pathological conditions – such as growth, pregnancy, illness or intense physical exertion – their need increases and can exceed the body's own synthesis capacity.
The nine essential amino acids and their biochemical functions
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Histidine : Precursor of histamine, a biogenic amine that functions in immune responses, gastric secretion, and as a neurotransmitter. Histidine is important for pH buffering in the blood and tissue repair.
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Isoleucine : A branched chain amino acid ( Branched Chain Amino Acids ( BCAA), which serves as an energy substrate in the muscles, is involved in hemoglobin formation and influences glucose metabolism.
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Leucine : Also a BCAA that stimulates muscle protein biosynthesis via mTOR signaling and inhibits catabolic processes.
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Lysine : Essential for collagen and elastin synthesis , promotes calcium absorption and is involved in the formation of carnitine, which is essential for fat metabolism.
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Methionine : A sulfur-containing amino acid, a central methyl group donor ( SAMe ), and important for detoxification processes. Methionine acts as a start codon in translation.
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Phenylalanine : starting material for tyrosine, which in turn is needed for the synthesis of dopamine, noradrenaline, adrenaline and melanin.
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Threonine : Component of glycoproteins and structural proteins, essential for mucosal integrity in the digestive tract.
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Tryptophan : Precursor of serotonin (mood, appetite, sleep), melatonin (sleep-wake cycle), and niacin (vitamin B3). Important in the regulation of mood and circadian rhythms.
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Valine : BCAA, provides energy to the muscles, supports regeneration and is involved in maintaining nitrogen balance.
The biological value of a protein indicates how efficiently it can be converted into the body's own protein. A complete and balanced amino acid profile maximizes this efficiency. If an essential amino acid is only present in limited quantities ( limiting amino acid ), all protein synthesis is inhibited – even with sufficient intake of other amino acids. Justus von Liebig's law of the minimum applies here as it does in plant nutrition . Knowledge of the total protein amount and also the specific amino acid pattern are important.
Primary protein sources and their profile characteristics
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Animal proteins : Meat, fish, eggs, and dairy products offer a complete amino acid profile containing all nine essential amino acids in optimal ratios and are characterized by a high biological value. These proteins are particularly efficiently absorbed because their amino acid pattern closely matches human needs, making them ideal sources for muscle building, regeneration, and maintaining physical functions.
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Plant proteins : Pulses, pseudocereals (quinoa, amaranth), soy, nuts, and seeds are rich in valuable amino acids and also provide secondary plant substances, fiber, and healthy fats. However, many plant sources have a limiting amino acid profile , for example, low lysine content in grains or methionine in legumes. However, a complete profile can be achieved through targeted combinations (e.g., grains + legumes, nuts + legumes). In addition, high-quality plant protein powder —such as from peas, rice, or hemp—can be used specifically in a plant-based diet to fill amino acid gaps and increase biological value.
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Supplements : isolates, hydrolysates or free EAAs (Essential Amino Acids can be used specifically to compensate for deficiencies. This is particularly relevant in competitive sports, during periods of increased physical or mental stress, in clinical nutrition, or during periods of increased regeneration needs.
Practical recommendations
An integrative approach with a mix of animal and plant protein sources is ideal for most diets. Vegetarian and vegan diets require special attention to combining different protein sources to ensure an adequate EAA supply. In dietetics, targeted amino acid analyses and supplementation can help prevent deficiencies and support recovery.
Conclusion
A thorough understanding of amino acid profiles is relevant not only for athletes, but for anyone who wants to maintain or improve their health, performance, and quality of life. Understanding how amino acids work in the body and the importance of a complete profile allows you to tailor your diet to ensure that all essential amino acids are consumed in sufficient quantities. This not only promotes muscle growth and faster recovery, but also supports hormone regulation, the immune system, healthy metabolic processes, mental performance, and long-term health maintenance into old age.
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Tessari, P., Lante , A. & Mosca, G. Essential amino acids: master regulators of nutrition and environmental footprint?. Sci Rep 6, 26074 (2016). https://doi.org/10.1038/srep26074
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