Methionine

Brand Names:

Clinical Names: Methionine

Summary

Methionine

chemical name: Methionine

related substance: S-adenosyl methionine (SAMe)

overview of interactions:
• nutrient affected by drug: Vidarabine

chemistry/function:
• Methionine is an essential sulfur-containing amino acid that facilitates the helps initiate the translation of messenger RNA by being the first amino acid incorporated into the N-terminal position of all proteins. The terminal methyl group of the methionine side chain often participates in biochemical methyl transfer reactions making methionine a member of the "methyl donor" class of biochemicals.
• Methionine is converted into S-adenosyl methionine (SAMe), which is considered to be the activated form of methionine. This happens in the first step of the metabolism of methionine. This step requires energy in the form of ATP. In this activation of methionine, an adenosyl moiety is transferred from the ATP molecule. SAM synthesis is one of the most potent methyl donors and is involved in many methylation reactions. Its methyl group, which is attached in a sulfonium linkage with high-energy characteristics, may be donated to any of a large number of methyl-group acceptors in the presence of the appropriate enzyme. SAM is intimately involved in the synthesis of brain chemicals and also in detoxification reactions.
• Methionine performs as a sulfur donor and, as such, is the source of sulfur for biosynthesis of cysteine.
• Methionine is also considered a member of the group of compounds called lipotropics.

dietary sources: Dairy, fish and meat are considered the richest dietary sources of methionine. Sunflower seeds are also a good source of methionine. Soybeans are a poor source and soy-based infant formulas are generally low in methionine. Egg yolks are particularly high in sulfur. Methionine and cysteine make up 91% of the sulfur in the yolk. Average intake in the U.S.: 2.7 to 5 g per day. Bacteria in the gut may be able to synthesize significant amounts. Homocysteine in the diet can eliminate the requirement for methionine.

deficiency:
• Methionine deficiency is usually related to overall protein malnutrition. Experimentally, a methionine deficiency causes premature atherosclerosis in monkeys, especially if they are also deficient in vitamin B6. Methionine deficiency can also cause a folate deficiency since a deficiency causes 5-methyl-tetrahydrofolate to accumulate in the liver.

known or potential therapeutic uses: Acrodermatitis enteropathica, migraine headaches, pain control, radiation effects, Wilson's disease.

maintenance dose: Dietary sources of methionine are usually adequate so supplemental methionine is usually not considered necessary. Optimal levels of intake have not been established.

therapeutic dose: 0.5 - 3 g per day.

side effects: Methionine is generally considered to be free of side effects for most individuals and 1 - 3 g per day is usually tolerated well by most adults. Some sensitive individuals may experience gas, bloating and digestive discomfort at levels as low as 500 mg per day. Diets high in methionine may be associated with an increased occurrence of atherosclerosis, especially with concurrent deficiencies of vitamin B6, vitamin B12 and folic acid.

toxicity:
• Although it rarely occurs, nausea and gastrointestinal irritation are signs of methionine toxicity.
• In cases of strong family history of coronary heart disease, it is wise to check homocysteine levels before and during treatment.
• Rats fed methionine as 50% of dietary protein (equivalent human dose of 25 g per day) exhibited hyperactivity, anorexia, reduced growth, iron accumulation in the spleen

contraindications:
• Osteoporosis: large doses increases urinary excretion of calcium.



Interactions

nutrient affected by drug: Vidarabine

• mechanism: Vidarabine is known to interfere with methionine synthesis.
(Med Lett Drugs Ther 1977 May 20;19(10):42-43; Cantoni GL, et al. N Engl J Med 1982 Oct 21;307(17):1079.)

• nutritional concerns: Individuals taking vidarabine for an extended period of time should consult with their prescribing physician to discuss options for countering the potential adverse effects of this drug. Some nutritionally oriented physicians have found value in monitoring serum methionine in their patients taking vidarabine.


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Do not rely solely on the information in this article.

The information presented in Interactions is for informational and educational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, case reports, and/or traditional usage with sources as cited in each topic. The results reported may not necessarily occur in all individuals and different individuals with the same medical conditions with the same symptoms will often require differing treatments. For many of the conditions discussed, treatment with conventional medical therapies, including prescription drugs or over-the-counter medications, is also available. Consult your physician, an appropriately trained healthcare practitioner, and/or pharmacist for any health concern or medical problem before using any herbal products or nutritional supplements or before making any changes in prescribed medications and/or before attempting to independently treat a medical condition using supplements, herbs, remedies, or other forms of self-care.



References

[No author given] Vidarabine (Vira-A). Med Lett Drugs Ther 1977 May 20;19(10):42-43.

Bidard JN. et al. Effect de la SAM sur le catabolisme de la dopamine. J Pharmacol. (Paris) 1977; 8, I:83-93.

Burger R., and Nowak H. A new medical approach to the treatment of osteoarthritis: Report of an open phase 1V study with ademetionin (Gumbaral) SAM. Am J Med 1987; 83:(suppl 5A), 84-88.
Abstract: Over 20,000 patients with osteoarthritis of the knees, hip, spine and fingers were studied over an 8 week period. Patients received 400 mg t.i.d. for first week, then 400mg bid for second week and 200mg bid from the third week on. No added treatment was permitted. The results revealed 71% of the patients had very good or good response which is comparable to NSAIDS but without the side effects.

Cantoni GL, Aksamit RR, Kim IK Methionine biosynthesis and vidarabine therapy. N Engl J Med 1982 Oct 21;307(17):1079. (Letter)

Caruso I, Pietrogrande V. Double blind, multicenter study comparing SAM, naproxen, and placebo in the treatment of degenerative joint disease. Am J Med 1987 83:(suppl 5A), 66-71. [Article in Italian]

Glorioso S, et al. Double blind, multicenter study of the activity of SAM in hip and knee osteoarthritis. Int J Clin Pharmacol Res 1985; 5, 39-49.

Kagan BL, et al. Oral SAM in depression: A randomized, double blind placebo-controlled trial. Am J Psychiatry 1990; 147:591-595.

Marcolongo R, et al. Double blind, multicenter study of the activity of SAM in hip and knee osteoarthritis. Current Ther Res 1985; 37:82-94.

Marz, Russell. Medical Nutrition From Marz. Second Edition. Portland, OR. 1997.

Muller-Fassbender H. Double blind, clinical trial of SAM versus ibuprofen in the treatment of osteoarthritis. Am J Med 1987; 83 (suppl. 5A), 81-83.

Rosenbaum JF, et al. An open label pilot study of oral SAM in major depression. Psychopharmacol Bull 1988; 24:189-194.

Salmaggi P, et al. Double blind, placebo-controlled study of SAM in depressed postmenopausal women. Psychotherapy Psychosom 1993; 59:905-113.

USDA: Composition of Foods. USDA Handbook #8 Washington DC, ARS, USDA, 1976-1986.