What are the main sources of phenylalanine

amino acids

  • Top Topics

    hay fever

    The nose is runny, the eyes itchy: Spring is not a good time for hay fever sufferers. What you can do.

    Go outside

    Overcoming your weaker self: We have 10 arguments for you why you should exercise outdoors.

    Breast cancer

    Breast cancer is the most common cancer in women. If it is recognized in time, the chances of treatment are good.
  • Diseases & Symptoms
  • Prevention & Health


    A healthy and balanced diet supports the immune system and can protect against many diseases.

    Fitness and wellness

    Sport and relaxation are good for body and soul. The best fitness exercises, tips for skin and hair and relaxation for the soul.

    Skin care

    Proper skin care should be tailored to the individual skin type. What do I have to consider?
  • Age & care

    Health in old age

    Much changes in old age. You can find information and tips on the topics of sexuality, sport and avoiding falls here.

    Advice and help in everyday life

    What should you watch out for when driving, how do you adapt your apartment to your age? The following information about tools, legal and counseling services.

    Care, Finance & Law

    The number of people needing care increases. You can find out everything you need to know about long-term care insurance, retirement homes and rehabilitation here.
  • Homeopathy & Naturopathy

    Medicinal plant lexicon

    Medicinal plants help against many ailments - the knowledge about the effects of the plants has often been passed down over millennia.

    Homeopathic remedies

    Homeopathic remedies have been used to naturally support health and wellbeing for over 200 years.

    Bach flowers

    Essences of Bach flower should have a harmonizing effect. The teaching according to Dr. Bach says that diseases can be cured by it.
  • Videos & self-tests

Amino acids are not just building blocks of Proteins and thus of body structures, they also have special tasks in metabolism - as messenger substances, in immune modulation and in hormone synthesis. The main source of amino acids is animal protein - that is, meat, sausage, fish, milk and eggs. But plants also serve as amino acid suppliers, for example nuts, soy, whole grain products and legumes.

© Shutterstock
According to nutritional-physiological aspects, a distinction is made between expendable (essential), indispensable (non-essential) and conditionally indispensable (semi-essential) amino acids. The L-amino acids are often also given without the addition of L-.
  • Indispensable (essential) amino acids cannot be produced by the body itself, so they have to be taken in with food. They include: L-isoleucine, L-leucine, L-lysine, L-methionine, L-phenylalanine, L-threonine, L-tryptophan, and L-valine.
  • Conditionally indispensable (semi-essential) amino acids can be produced by the body, but must also be supplied in infancy, in the event of malnutrition or certain serious illnesses. These include: L-arginine, L-cysteine, L-tyrosine, L-serine and L-histidine. In some cases, L-glutamine can also be semi-essential.
  • Dispensable (non-essential) amino acids can be produced by the body itself. They include L-alanine, L-asparagine and L-aspartic acid, L-glutamic acid, glycine, L-glutamine and L-proline.
If amino acids are supplied to the body outside of normal nutrition (enteral supply) - for example via an infusion (parenteral) - the amino acids often have different effects. Therefore, the results of studies examining parenteral nutrition can usually not be transferred to normal nutrition.

Functions of individual amino acids in the organism

Contributes to the structure of the cells. Serves as an important energy supplier in cellular processes. Is an important messenger substance in the nervous system. Is an important part of most body proteins. The amino acid also strengthens the immune system, is involved in detoxification processes and promotes body growth. An additional intake of arginine is not recommended from a nutritional point of view, as more harmful nitric oxide is formed and the immune system is inhibited. Important for detoxification processes and for the immune defense. Also has an antioxidant effect. An additional supply is usually given as an infusion solution to the seriously ill - such as patients after a bone marrow transplant, with severe burns or radiation damage. An additional intake is also advisable for new and premature babies, which is why cysteine ​​is often added to baby food. Strengthens the immune system and protects the mucous membrane of the small intestine. Promotes muscle and length growth. Glutamine is also usually administered as an infusion solution to seriously ill patients - such as patients after a bone marrow transplant, with severe burns or radiation damage. Important messenger substance for the central nervous system, increases concentration and performance. Also involved in the body's detoxification processes.
Found in many cells because it is involved in the structure of the structure. In the central nervous system it acts as a neurotransmitter, i.e. as a messenger substance. Formation of the red blood pigment hemoglobin, a key function in allergic and inflammatory diseases.
  • Isoleucine, Leucine, Valine:
Promote the building of muscle tissue. Promotes collagen formation in blood vessels, skin, bones and teeth. Supports calcium absorption from the intestines and incorporation into the bones. Important for the formation of cell membranes, for the nervous system, detoxification processes and the regulation of the acid-base balance. Important for the production of various hormones such as dopamine, adrenaline, noradrenaline, thyroxine. Partly used for depression.
Mainly needed for the development of connective tissue - but also acts as a buffer. Has an antioxidant effect, is involved in detoxification processes, stabilizes the nerve cells, regulates the heart function and strengthens the immune system. Important for body growth. Important for the production of the neurotransmitter serotonin. This regulates the sleep-wake rhythm, mood, appetite and pain perception. Also important for the formation of the hormone melatonin and vitamin B3. Is formed from phenylalanine and required for the formation of the messenger substances dopamine, noradrenaline, adrenaline and the thyroid hormones. Melatonin and coenzyme Q10 are also formed from tyrosine. Found in almost all proteins in the body.
  • Author: Dr. med. Petra Kittner-Schäfer
  • Swell: H.K. Biesalski, Vitamins, Trace Elements and Minerals, Thieme Verlag 2002
  • K. Glagau, Micronutrients and Nutrition, Forum Medicine 2001
  • W. Busse / H. Scholz, The ABC of Vital Substances, Haug Verlag 2001
  • DGE, reference values ​​for nutrient intake 2000
  • Lacey, JM / Wilmore, DW: Is glutamine a conditionally essential amino acid? (http://www.ncbi.nlm.nih.gov/pubmed/2080048)
  • Fontana Gallego, L et al .: Nitrogenous compounds of interest in clinical nutrition (http://www.ncbi.nlm.nih.gov/pubmed/16771070)
  • Müller, Manfred James: Nutritional Medicine Practice: Methods - Prevention - Treatment
  • Bechthold, Angela: Reference values ​​for nutrient intake: (https://www.ernaehrungs-umschau.de/fileadmin/Ernaehrungs-Umschau/pdfs/pfd_2009/06_09/EU06_346_353.qxd.pdf)
  • Federal Institute for Risk Assessment (BfR): Food supplements - distribution through doctors and pharmacists (http://www.bfr.bund.de/cm/343/nahrungsergaenzemittel_vertrieb_ueber_aerzte_und_apotheker.pdf)
  • German Cancer Information Center: Dietary Supplements: Big Promises, No Effect? (https://www.krebsinformationsdienst.de/verarbeitung/nahrungsergaenzemittel.php)

You might also be interested in: