L-methionine is an essential sulfur-containing amino acid that is soluble in water. It is a powerful antioxidant, assists in the breakdown of fats, and helps inactivate free radicals. Because it is an essential amino acid, it must be supplied in the diet. The recommended daily intake is 13 mg per kg or about one gram daily for adults. The actual intake is higher due to the fact that it is principally derived from dietary proteins. Cheese, eggs, fish, meat and poultry are all rich sources of L-methionine. It can also be found in fruits and vegetables, but not as abundantly.
