Methionine is an essential amino acid. It is the dietary precursor to both cysteine and taurine, versatile compounds such as SAM-e and essential antioxidant glutathione, methione has a crucial role in metabolism or health of human. It is encoded by codon AUG. It is a vital part of angiogenesis which is the growth of new blood vessels. Its supplementation is beneficial for those with copper poisoning. Similarly, overconsumption of methionine is associated to growth of cancer. Firstly methionine is isolated by John Howard Mueller in 1921.
L-isomer of methionine is the only form which is involved in protein synthesis and is one of the 20 standard amino acids being common in animal proteins and necessary for normal functioning in humans. It is regarded as an essential amino acid as it could not be incorporated by the human body from other compounds through chemical reactions and should be taken from diet.
As it is encoded by single codon AUG, it carries start message from ribosome to begin protein translation from mRNA. As an effect, methionine is included into N-terminal position of all proteins in eukaryotes and archae during translation though it is removed by post translational modification. This role discloses remarkable unity among living organisms. Moreover, precision is required for functional protein which involves a particular arrangement of amino acids and distinct dimensional folding of protein that reflects on complex coordination in nature.
It is needed for growth and repair of tissues. Methionine is a sulphur containing amino acid which improves tone or pliability of skin, hair and strengthen nails. It is involved in various detoxifying processes; sulfur from methionine prevents cells from pollutants and slows aging of cells. It is required for absorption and bio-availability of zinc and selenium. It chelates mercury and lead assisting its excretion. It acts as a lipotropic agent preventing excess buildup of fat in the liver.
Food Sources of Methionine
| Food name | Weight (g) | Methionine (g) |
| Turkey | 863 | 7 |
| Brazilnuts | 133 | 1 |
| Seaweed, spirulina | 112 | 1 |
| Fish, tuna | 146 | 1 |
| Goose | 143 | 1 |
| Tilefish | 150 | 1 |
| Rockfish | 149 | 1 |
| Kielbasa | 370 | 1 |
| Cheese, swiss | 132 | 1 |
| Fish, haddock | 150 | 1 |
| Mollusks, whelk | 85 | 1 |
| Soybeans | 186 | 1 |
| Cheese, fontina | 132 | 0.932 |
| Sesame seeds | 144 | 0.844 |
| Teff | 193 | 0.826 |
| Cheese, colby | 132 | 0.821 |
| Seeds, cottonseed kernels | 149 | 0.788 |
| Mungo beans | 207 | 0.760 |
| Cheese, muenster | 132 | 0.751 |
| Cheese, parmesan | 100 | 0.751 |
Health Benefits of Methionine
Here we will discuss about the health benefits that Methionine offers:
- Parkinson’s disease
Research has shown that deficiency of Methionine is associated to Parkinson’s disease. So one should ensure to add diet rich in Methionine which helps to mitigate or counter the effects of this neurodegenerative disease.
- Lose weight
Methionine is one of the crucial ingredients in creatine which promotes muscle development at a investment of fat. It helps to promote metabolic rate and supports weight loss.
- Stronger bones
This supplement is used by many athletes to aid development of bone and its strength which is essential for athletes if one is suffering some kind of injury.
- Stronger immunity
Adequate methionine in the body is associated with presence of other amino acids which are involved in immune function. It is a precursor of these immune boosting amino acids which benefits defense and repair.
- Useful for urinary tract infections
Methionine acidifies body when it is used in form of supplement referring that it makes urine slightly more acidic. It is unsafe for urinary tract infections to take hold yet preventing women from this problem with recurring UTIs.
- Detoxify body
With other nutrients and compounds, it stimulates liver function and lowers the effects of liver diseases hence detoxifying body in the process.
- Treat colorectal cancer
Research shows the risk prevention and treatment of methionine effects on colorectal cancer. High level of amino acids ensures proper formation of antioxidant in the body such as glutathione. Methionine supplementation is required for those who are more prone to chronic diseases.
- Raises Glutathione
Methionine and cysteine are not stored by the body. The deficiency of sulfur amino acids such as methionine, the level of glutathione suffer more than critical processes such as protein synthesis. Excess dietary is oxidized to sulfate and excreted in urine or stored in form of glutathione. Levels of glutathione are inferior in various diseases and following some medications that could be reversed with an intake of methionine. Sulfur and methionine should be able to spare glutathione losses related with deficiencies of dietary, surge utilization due to disease and altered immune function. In low methionine conditions, synthesis of sulfate & Glutathione will be lowered which negatively influence immune function and antioxidant defense mechanisms.
- Healthy gut
Methionine (dietary) is crucial to ensure intestinal health and immune function during development and inflammatory states. When healthy piglets are fed deficient diet, supplementation with methionine (25 g/kg) and cysteine (0.25 g/kg) had low intestinal oxidative stress, improved villus height and area and crypt depth and high number of goblet cells.
- Joint health
Sulfates are important for glycosaminoglycan synthesis which is essential for cartilage. Study concludes that significant proportion of population which included disproportionally the aged, do not receive sufficient sulfur and these dietary supplements are likely to exhibit its pharmacological activities by supplying sulfur. For growth, diets of chicken are supplemented with methionine or cysteine.
Toxicity
High doses of methionine can be metabolized to homocysteine which is a toxic metabolite. Homocysteine production is lowered by an intake of Vitamin B6 with methionine. High dose of methionine promotes urinary excretion of calcium and must be avoided by women or with high chances of osteoporosis. When used in high doses by schizophrenia patients, they may aggravate hallucinations.
Side effects
Overdose of methionine causes side effects such as nausea, vomiting, complications for pregnant women, high chances of liver disease, constipation and bad breath.
References:
https://pubchem.ncbi.nlm.nih.gov/compound/L-methionine#section=Top
https://en.wikipedia.org/wiki/Methionine
http://www.newworldencyclopedia.org/entry/Methionine
https://www.organicfacts.net/methionine.html
https://www.selfhacked.com/blog/methionine-good-bad-surprising-truth-methionine-restriction/