Having the MTHFR gene mutation, additional SNP’s in the methylation pathway, or poor methylation can contribute to histamine intolerance as the primary function of the methylation pathway is to produce the methyl donor called SAMe (also known as s-adenosyl methionine). SAMe is a cofactor for the HNMT enzyme, which metabolizes intracellular histamine inside the cell. Learn about the connection between MTHFR and histamine and what you need to know about deficiencies in B vitamins and histamine ~ Didem