These are the key nutritional players in the methylation system:
o Methionine is an amino acid found in all proteins, but which is especially rich in animal products. After being activated using ATP, the fundamental energy currency of the cell, methionine becomes the universal methyl donor.
o Once activated methionine donates its methyl group, it becomes homocysteine. Homocysteine needs to be recycled back to methionine so methylation can continue, and homocysteine itself is thought to be harmful by contributing to cardiovascular disease.
o Vitamin B12 and folate (vitamin B9) recycle homocysteine back to methionine. They take the methyl group from the metabolism of amino acids that we get from dietary protein.
o Alternatively, betaine (trimethylglycine, TMG), which is mainly derived from choline, recycles homocysteine back to methionine.
o Several other B vitamins, mainly thiamin (vitaminB1), riboflavin (vitamin B2), niacin (vitamin B3), and pyridoxine (vitamin B6), support B12 and folate in recycling methionine, even though they themselves are not methyl donors.
o Glycine is our buffer for excess methyl groups.
o A number of minerals are needed to support the enzymes involved in this system: iron, phosphorus, sulfur, magnesium, potassium, zinc, and possibly cobalt. Vitamin A is also needed to produce the enzyme involved in using glycine as a methyl buffer.
https://chrismasterjohnphd.com/blog/201 ... thylation/