Under stress, in exceptional situations or during extreme physical exertion, people often excel, are more alert, more focussed and more efficient. This is due to the fact that various physical processes are triggered that produce precisely these effects. They are controlled by hormones, which are then increasingly released, including dopamine, adrenaline and noradrenaline. However, in order for these processes to be set in motion, certain starting substances are required. One of these starting substances is the amino acid tyrosine or L-tyrosine. Here you can find out what effect it has in the body, how to ensure a sufficient supply with the right diet and what symptoms occur in the event of a deficiency.
What is tyrosine or L-tyrosine?
Tyrosine in its natural L-form, also known as L-tyrosine, is a proteinogenic semi-essential amino acid that is found in the majority of all proteins. Amino acids that are required for the formation of proteins in the human body are referred to as "proteinogenic". Tyrosine is the starting material for various neurotransmitters and hormones, such as dopamine, noradrenaline, adrenaline and thyroxine.
Why is tyrosine not an essential amino acid?
Essential amino acids are characterised by the fact that they cannot be produced by the human body itself, but must be supplied through the diet. We have summarised more information on essential amino acids here. Although L-tyrosine is contained in many foods, it can also be produced by the body itself. Phenylalanine, an essential amino acid from which L-tyrosine is formed, is required for synthesis in the body.
What effect does tyrosine have in the body?
L-tyrosine is formed during the breakdown of proteins and is synthesised in the body from phenylalanine. L-tyrosine is involved in many chemical processes in the body, such as the formation of proteins and the function of the adrenal glands, the pituitary gland and the thyroid gland, as well as the formation of hormones and messenger substances that are produced there. Tyrosine is a building block of numerous proteins, especially those involved in signalling. These transmit information from one cell to another. This effect increases general motivation.
Adrenaline: The hormone produced from L-tyrosine in the adrenal gland has various functions and effects. Adrenaline is released during stress, it increases the heart rate and the capacity of the lungs, among other things. All these physical adaptations caused by adrenaline are important in order to be able to react quickly in dangerous situations or under stress.
Dopamine: The neurotransmitter is produced in the adrenal medulla as a by-product of the synthesis of adrenaline triggered by tyrosine. Dopamine is also known as the "happiness hormone". It increases drive and motivation [1].
Noradrenaline: This hormone is also produced in the adrenal glands and released into the blood from there, increasing blood pressure.
Triiodothyronine (T3) and thyroxine (T4): L-tyrosine is also a starting material for the formation of these two hormones in the thyroid gland. They are required for the growth of individual cells and the entire body. They also regulate the body's energy balance by controlling and adjusting the metabolism.
Melanin: Tyrosine also acts as a starting material for the pigment melanin. Melanin is responsible for the brownish-black colouring of skin, hair and eyes.
Through its involvement in these various processes, tyrosine can have an energy-boosting effect and an effect on stress resistance, as various studies have shown [2,3,4,5]. L-tyrosine is also said to have a positive effect on cognitive performance [6], have a mood-enhancing effect and even help with depression [7,8].
Which foods contain tyrosine?
L-tyrosine is found in numerous foods, especially foods containing protein, such as meat, fish, nuts and seeds, pulses, cereals, eggs and milk. Many purely plant-based, vegan products also contain high levels of the amino acid. For example, these foods contain tyrosine in the following doses:
- White beans: 870 mg tyrosine per 100 g
- Cod: 709 mg tyrosine per 100 g
- Gouda: 1204 mg per 100 g
- Meat: 710 mg per 100 g
- Cooked ham: 946 mg per 100 g
- Peanuts: 1211 mg per 100 g
How much tyrosine do you need per day?
An adult needs between 14 and 33 mg of tyrosine per kilogramme of body weight per day. This amount can be absorbed through food or produced by the body itself. With a balanced diet, the daily requirement is usually covered. The daily requirement increases during pregnancy or when breastfeeding. During this time, special attention should be paid to a tyrosine-rich diet.
How and when should tyrosine be taken additionally, e.g. as a dietary supplement?
In healthy people, the intake of L-tyrosine through food is usually sufficient, so a deficiency rarely occurs. Dietary supplements containing L-tyrosine are also sold. But be careful: an overdose of L-tyrosine can have consequences if the amino acid cannot be broken down for hereditary reasons, for example.
What symptoms can indicate a tyrosine deficiency?
Side effects of an L-tyrosine deficiency can manifest themselves through various symptoms, including weakened defences, cardiovascular disorders, depressive moods, tiredness and fatigue, declining cognitive and coordination skills as well as fluctuations in insulin and blood sugar levels. Tyrosine deficiency can also affect hormone production in the thyroid gland.
What can cause a tyrosine deficiency?
People with liver disease are at an increased risk of suffering from a deficiency, as the synthesis of phenylalanine into tyrosine can be impaired by long-term, perhaps even chronic illnesses. Another disease that can cause a deficiency is the metabolic disorder phenylketonuria. Affected individuals are generally unable to synthesise tyrosine from phenylalanine. Another side effect of this disease is developmental disorders caused by phenylalanine not being metabolised.
Sources:
[1] https://today. uconn.edu/2012/11/uconn-researcher-dopamine-not-about-pleasure-anymore/
[2] https://www.ncbi.nlm.nih.gov/books/NBK209061/
[3] https://pubmed. ncbi.nlm.nih.gov/26424423/
[4] https://pubmed.ncbi.nlm.nih.gov/25797188/
[5] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1863555/
[6] https://link.springer.com/article/10.1007/s00426-017-0957-4
[7] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5020390/
[8] https://pubmed.ncbi.nlm.nih.gov/6764934/
