Amino acids are molecules that combine to form proteins in food and the body. Of the 20 required amino acids, 9 are essential, ie they must be supplied with the diet because our body does not synthesize them. Phenylalanine is one of them.
It is these units that aid in tissue growth and repair. They also work to make other amino acids, make antibodies, some hormones, and build muscle.
The foods that contain the most are those of animal origin and some vegetables. There are artificial sweeteners made with phenylalanine. However, despite its benefits, one must be wary of excessive consumption.
To find out more about the functions of this interesting amino acid, where it is found naturally and the recommended doses, please continue reading the article.
What is Phenylalanine?
Phenylalanine, like 8 other amino acids, it must be ingested with food because the body does not synthesize it. That is why it is considered an essential amino acid.
It is known by the acronym f OR Fe and is found in protein in its natural form as L-phenylalanine. D-phenylalanine or DPA forms and a mixture thereof known as DL-phenylalanine or DLPA, synthesized in the laboratory, are also produced.
From a chemical point of view it is considered an aromatic amino acid. Not for its aromas, but because it is linked to a benzene ring which makes it insoluble in water.
It performs some important functions within our body, including the production of other amino acids, such as tyrosine. Also other biologically important molecules are synthesized, such as hormones and neurotransmitters.

Functions of phenylalanine
Why comment on this particular amino acid? Decidedly, its functions are extensive.
1. Helps relieve pain
Synthetic D-phenylalanine has been proposed for the treatment of chronic painsuch as arthritis, fibromyalgia and osteoarthritis, as it blocks the enkephalinasean enzyme that increases pain levels in the body.
When faced with very intense pain, the body releases opioid neurotransmitters which have a natural analgesic effect. Some of these are i endorphins, dynorphins and enkephalins. the enzyme enkephalinase breaks down these painkillers, but D-phenylalanine is able to prevent their exhaustion.
2. Maintains good brain activity
Phenylalanine not only blocks enzymes, but also it also allows the synthesis of other neurotransmitters that maintain mental functioning. Some of them are dopamine, norepinephrine and epinephrine.
Neurotransmitters also help stop the degeneration of neurons due to aging. Some diseases that are delayed in their progression by the amino acid phenylalanine are Alzheimer’s and Parkinson’s.
3. Can form tyrosine
THE tyrosine It is a non-essential amino acid, but as important as the other 19 that are part of the body. Phenylalanine is converted into tyrosine, which is a precursor to the hormone that regulates the thyroid gland.known as thyroxine. This hormone performs several vital functions.
Tyrosine is also associated with the synthesis of the neurotransmitters adrenaline and dopamine. These suppress appetite and reduce body fat.
On the other hand, Tyrosine is essential for the production of melanin. This is the pigment responsible for hair and skin color.
4. Regulate your appetite
Phenylalanine, together with tryptophan, controls appetite. They stimulate the secretion of a hormone called cholecystokinin. This is considered an appetite suppressant and is produced in the major portions of the small intestine where fats are digested.
5. Puts you in a good mood
Phenylalanine stimulates the production of endorphinsknown as happiness hormones. Together with dopamine, serotonin and oxytocin, they regulate mood, help manage stress and improve mood. For this reason it is recommended for overcoming diseases such as depression and anxiety.
Phenylalanine is part of the formulation of a variety of psychotropics as an adjuvant. Thus, it improves the functions of the central nervous system.
Foods that increase phenylalanine
Phenylalanine is found in protein foods of animal and plant origin. But which of them should be selected to ensure a good supply in the diet?:
- Legumes: soybeans, chickpeas, lentils, beans of different colors, contain high protein values. More than 18% when it comes to dried legumes. Part of these proteins is phenylalanine. THE recommended service It is about 60-80 grams of raw legumes, 3 times a week.
- Red meat: It provides proteins with a high nutritional value, as they contain almost all the essential amino acids.
- Fish: they also provide essential amino acids such as phenylalanine and tryptophan. Additionally, salmon, mackerel, tuna, sardines and sea bass provide polyunsaturated fats such as EPA and DHA.
- Egg: the most complete protein of all is albumin, which predominates in egg white.
- Nuts: They are a source of protein with a high supply of essential amino acids. Other nutrients present are unsaturated fats, such as omega 3, and various minerals.
It is important to remember that phenylalanine is found hidden in some artificial sweeteners. For this reason, those people suffering from the genetic disease known as phenylketonuriathey should avoid them.
Additionally, there are several food products such as sodas, juices, and milk-based beverages that are made with these sweeteners. Therefore, the product label should be read carefully.

Dosage and precautions in consumption
The requirement for L-phenylalanine is 100 milligrams per kilogram of body weight per day. If you eat a diet high in animal or plant-based protein, the Fe it can reach 500 milligrams per day.
It is recommended not to take it together with food or food products that contain caffeine. This alkaloid can decrease the absorption of the amino acid.
Phenylalanine supplements or concentrates should not exceed 2.4 grams per day. An overdose can cause nausea, diarrhea, vomiting, headache, dizziness and fever.
Phenylalanine is dangerous for some pathologies. For example, people with liver or kidney problems should take care of the amino acid intake and follow the instructions of a specialist. Pregnant women or people with phenylketonuria, undergoing radiation therapy or skin cancer should avoid the supplements.
Does food ensure phenylalanine intake?
Obviously. Food sources of L-phenylalanine, when included in the diet, ensure daily recommendations. In particular the analgesic functions, the production of neurotransmitters in the central nervous system, the secretion of hormones of good mood and happiness and the regulation of appetite.
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