An essential or indispensiable amino acid is an amino acid that cannot be synthesized de novo (i.e. from scratch) by the organism, and thus must be supplied in one’s diet.
According to William Cummung Rose’s (1887-1985) work, as well as later studies, nine amino acids are essential for both adults and infants: valine, phenylalanine, threonine, thryptophan, leucine, elecine, lysine, hystodine, and methionine. Arginine is also essential for infants.
If one broadens the scope there is also semi-essential and non-essential amino acids which are all of more or less relevance, but I will mainly focus on the essential ones and and how one can absorb them by to eat properly.
Good sources of essential amino acids are for instance white fish, chicken, eggs and quark, as well as various plants and fruits such as apples, bananas, sesame, broccoli, soybeans, tofu, carrots and seaweeds. Thus, for a vegetarian it is somewhat more tricky in this respect and even more so for a vegan.
Perhaps the most optimal approach – especially if one is interested in fitness – is to have a diet akin to for instance this one. The important thing is to cover all the essential and semi-essential amino acids and to avoid both over-consumption and deficits. If one eats moderately of animal protein sources, and/or large amount of relevant vegetable sources, then it will be just fine with regard to essential amino acids.
Additionally, as the quotes below indicate – which are both taken from a relevant study – it is also about nutritional balance and to overall cover all the known amino acids:
Western diets are characterized by high omega-6 and low omega-3 fatty acid intake, whereas during the Palaeolithic period when human’s genetic profiles were being established, there was a balance between omega-6 and omega-3 fatty acids as well as amino acids [1-3, 9-16]. Therefore, humans today live in a nutritional environment that differs from that for which our genetic constitution was selected. Cohort studies have demonstrated that European vegetarian diets of Seventh-Day Adventists, Mediterranean diet (fruit, vegetables, nuts, whole grains, olive oil, wine fish, chicken), Japanese diets; (vegetables, raw fish, whole rice), IndoMediterraneandiet (whole grains, fruits, vegetables, nuts and mustard oil) and the French paradox diet ( vegetables and wine) are protective against cardiovascular disease, diabetes and cancer. All these diets are rich in amino acids as well as w-3 fatty acids, however, only omega-3 fatty acids has been considered in the mechanism of benefit without any consideration for amino acids. The total energy from proteins may be approximately 16% en per day which is closer to huntergatherers diet.
Essential and nonessential amino acids consist of hydrogen, nitrogen, oxygen and carbon atoms. These simple molecules play an important role in the human body [5, 17- 19]. The 22 known amino acids, essential and nonessential, affect a broad range of physical and mental processes. Recent studies have witnessed the discovery that amino acids are cell signalling molecules as well as being regulators of gene expression and the protein phosphorylation cascade . Majority of the neurotransmitters can influence mind-body interactions and are composed of amino acids. Additionally, amino acids are key precursors for syntheses of hormones and low-molecular weight nitrogenous substances with each having enormous biological importance. Physiological concentrations of amino acids and their metabolites (e.g., nitric oxide, polyamines, glutathione, taurine, thyroid hormones, and serotonin) are required for the biological functions in our body. However, elevated levels of amino acids and their products (e.g., ammonia, homocysteine, and asymmetric dimethylarginine) are pathogenic factors for neurological disorders, oxidative stress, and cardiovascular disease. Thus, an optimal balance among amino acids in the diet and circulation is crucial for whole body homeostasis. There is growing recognition that besides their role as building blocks of proteins and polypeptides, some amino acids regulate key metabolic pathways that are necessary for maintenance, growth, reproduction, and immunity. They are called functional amino acids, which include arginine, cysteine, glutamine, leucine, proline, and tryptophan. Dietary supplementation with one or a mixture of these amino acids may be beneficial [5, 17-19] for ameliorating health problems at various stages of the life cycle (e.g., fetal growth restriction, neonatal morbidity and mortality, weaningassociated intestinal dysfunction and wasting syndrome, obesity, diabetes, cardiovascular disease, the metabolic syndrome, and infertility) . Amino acids can also optimize efficiency of metabolic transformations to enhance muscle growth, milk production, egg and meat quality and athletic performance, while preventing excess fat deposition and reducing adiposity. Thus, amino acids have important functions in both nutrition and health.
De essentiella aminosyrorna är valin, treonin, fenylalanin, trypofan, leucin, isoleucin, metionin, lysin och hystin. För barn är även arginin essentiell.
För att få i sig en tillräcklig mängd av dessa krävs i allmänhet det som av experter vagt brukar kallas en “allsidig och varierad kost”. Mer specifikt handlar det om till exempel animaliska, proteinrika källor som vit fisk, ägg, kyckling och kvarg, samt vegetabiliska dito, som sesamfrön, chiafrön, sojaprotein/tofu, jordnötter, bönor, broccoli, morötter och sjögräs.
Man kan förslagsvis följa dessa riktlinjer, och därmed äta en högre grad av animaliskt protein om man är fitnessutövande.