L – Methionine

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Human beings possess an essential amino acid known as L Methionine. This compound plays a vital part in the health and metabolism of multiple species and also in human beings. Moreover, it is a crucial bit of angiogenesis (development of new blood vessels).

Methionine Structure

Between two amino acids, Methionine contains sulphur while the other one is cysteine. Generally, every amino acid holds a similar structure that is an amino group connected to one hydrogen, one side is a chain group and the other is a carboxyl group. Moreover, Methionine's chemical formula is C5H11NO2S, and its side chain is C2H7S.

Following is a diagram that shows Methionine structure

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Dietary Sources of L –Methionine

High concentrations of L-methionine are present in meat, eggs, Brazil nuts and sesame seeds. Notably, it is also available in some seeds of plants and cereals. However, maximum vegetables and fruits hold low levels of L-Methionine.

Maximum legumes have a low amount of protein content, and hence they are low in L-Methionine. Moreover, the protein sources which do not have enough of L-Methionine are not counted as complete proteins. Due to this reason, sometimes pet foods are mixed with racemic Methionine.

Furthermore, individuals must not overcook or excessively boil food products containing L – methionine. It may damage the amino acid structure as they are hugely soluble.

A Tabular Representation Showing Sources of Food Containing Methionine.

Sources of Food




Flour from sesame seeds


Rice (cooked, brown, medium-grain)




Parmesan and shredded cheese






Tuna fish


Wheat germ






Seeds of chia


Roasted, fried and boiled chicken


Yellow corn








Effectiveness Of L Methionine

The most important use of Methionine is for the treatment of acetaminophen poisoning. Although there is a lack of evidence, this amino acid may also be useful for the following diseases:

  • Breast Cancer

Humans who intake high quantities of Methionine are less prone to breast cancer.

  • Parkinson's Disease

Some studies suggest that if individuals take L-methionine via food for at least six months, they may experience improvement in Parkinson's disease symptoms like tremor, rigidity and incapability of controlling movements.

  • Neural Tube Defects at the Time of Birth

Females who eat more amounts of L-methionine during their pregnancy may have a reduced risk of neural tube issues.

Apart from the mentioned diseases, Methionine can improve several other health conditions like herpes simplex virus (HSV), pancreatitis, asthma, schizophrenia, depression, liver function, shingles, human papillomavirus, allergies, urinary tract infections, etc.

Moreover, there are other Methionine uses as well. It can be used as an additive to dogs as it assists in lessening the growth of kidney stones in them. Also, it acts as a pesticide to fight against caterpillars (giant swallowtail) which damage orange crops.

Impact On Health

Reduction of L-methionine is related to hair greying. Due to loss of this amino acid, hydrogen peroxide gets built up in follicles of hair which results in lack of tyrosinase effect. Hence, it further leads to hair discolouration.

On the other hand, large doses of Methionine may affect the human brain and cause heart diseases. Also, it can enhance the development of a few tumours. Hence, Methionine must not be used by self-medication.

Do It Yourself

1. L – methionine is essential for growth of _________ ________ in the human body.

2. High levels of methionine is available in _________, _________, _________ and _________.

3. L – methionine is vastly used for the treatment of __________ __________.

4. The chemical formula of methionine is _________.

To discover more about methionine structure, effects, use, and other associated topics, access our study notes and online sessions. Now you can also download our Vedantu app for better access to these study materials and interactive sessions.

FAQ (Frequently Asked Questions)

1. Why is Methionine Important?

Ans. Methionine is essential for the human body because it helps in producing important molecules and functioning of cells. Additionally, it also prevents liver damage during acetaminophen poisoning.

2. How can Someone Reduce Methionine?

Ans. By taking glycine, one can reduce Methionine as glycine enables the liver to eliminate Methionine from the human body. Furthermore, if a person eats a high amount of fruits and low quantities of legumes, nuts and grains, he/she will be able to restrict Methionine.

3. When Does Amino Acid Become Harmful?

Ans. When a human body holds high levels of amino acids it becomes harmful. Gastrointestinal disorders like abdominal pain and bloating may occur under such circumstances.