Gene expression can be regulated without changing the DNA sequence through what is called an 'epigenetic mechanism' that frequently involves 'methylation'. The attachment of a methyl group (-CH3) to one of the DNA building blocks (cytosine) stops the gene being read. These methyl groups come from choline, betaine, folate and vitamin B12.
Choline is the most common dietary source of methyl groups, but methionine (an amino acid) and carnitine (made from amino acid) are also important sources of methyl (-CH3) groups. Carnitine is found in animal source products like meat (the redder the higher the content) but also found in fish, poultry and milk.
Choline is an amino acid (glycine) that has been modified to carry 3 methyl (-CH3) groups.
Choline is the main dietary source providing methyl groups (-CH3, or single carbon units) to the body. It can be found in high concentration in liver and eggs. Every choline molecule brings three (3) methyl groups to be used in 'transmethylation metabolism'.
The Vitamin B Team. B12 (cobalamin) B9 (Folate) B6 (pyridoxine) and choline are interconnected in what is called 'transmethylation metabolism'. Foods containing these essential nutrients make 'methyl groups' or single carbon units (-CH3) available for use in the methionine pathway - critical to DNA expression.