Phenylalanine is an essential amino acid(EAAs). amino acids are the building blocks of protein And essential amino acids are amino acids that body cannot synthesize on its own and needs to acquire it from dietary sources. L-Phenylalanine has shown so far to help body create brain signaling molecules dopamine, norepinephrine or noradrenaline and epinephrine or adrenaline. Phenylalanine can also be converted to tyrosine(a non-essential amino acid).
There are three forms of amino acid phenylalanine: D-phenylalanine, L-phenylalanine, and the mix made in the laboratory called DL-phenylalanine. D-phenylalanine is not an essential amino acid and its role is not understood yet and is being synthesized for use in certain medical applications but L-phenylalanine is essential amino acid and is the only kind of phenylalanine found in proteins like meat and fish and cheese
Human body uses phenylalanine to generate chemical messengers, but we still do not know how it really does this process.
Phenylalanine seems safe for most people although for people who have the genetic disorder phenylketonuria (PKU) or certain other health conditions phenylalanine can become risky health wise. Phenylalanine may cause intellectual disabilities, brain damage and seizures and other problems in people with PKU.
The artificial sweetener aspartame which is added to many medications, diet foods and diet sodas, contains phenylalanine. That is why on all certified brands of diet soda labels you see warnings for people suffering from PKU.
Also since aspartame has phenylalanine and phenylalanine causes high levels of dopamine secretion and it also can be converted (through a separate pathway) to phenylethylamine, a substance that occurs naturally in the brain and appears to elevate mood, it may create high free radicals inside brain and may harm our body. Although some dopamine is essential for our health and overall feeling of satisfaction we have in life and brain development and learning(That is why permanent logical disability, impaired cognitive development are symptoms of Phenylalanine hydroxylase (PAH) deficiency), too much of it will counteract all the benefits mentioned.
Tyrosine is another amino acid that is produced from phenylalanine. It can be used to make new proteins or convert into other molecules.
Phenylalanine is also used for depression, attention deficit-hyperactivity disorder (ADHD), Parkinson’s disease, chronic pain, osteoarthritis, rheumatoid arthritis, alcohol withdrawal symptoms, and a skin disease called vitiligo.
Soy products are some of the best plant sources of this amino acid, as well as certain seeds and nuts, including soybeans, pumpkin seeds and squash seeds and nuts.
other Food sources are lentils, chickpeas, pecans, whole grains, peanuts, lima beans, cheese, cottage, corn, brewer’s yeast, bananas, almonds, dairy products, and eggs.
The recommended daily intake(RDA) of phenylalanine and tyrosine is 25mg per kilogram of body weight or 11mg per pound.