Inositol is a B-vitamin that acts as a lipotropic agent in a manner similar to choline. Since inositol can be synthesized from glucose, it is not thought to be essential as choline and methionine. Methionine is a sulfur-containing amino acid that is necessary to the synthesis of choline, cysteine, and taurine. When converted to cysteine, this sulfur compound acts as a liver antioxidant and detoxifier. Methionine is not abundantly available in vegetarian diets, but is found in dairy, eggs, fish, and meat, especially organ meats.
Vegetarian sources are legumes such as soybeans, and nuts and seeds.
Table 2 shows foods and herbs rich in methionine. Table 3 shows the levels of methionine in various forms of soy. Note that soy is high in both choline and methionine. 1997 Choline and methionine may be transformed into glutathione within the liver. Glutathione is needed by the liver to metabolize alcohol, hepatotoxins, and other toxic substances.