What is the Methylation Cycle?

What is the Methylation Cycle?

The methylation cycle is the process of transferring methyl groups (CH3) to DNA, turning switches off and on which change the gene expression but not the sequence. The methylation cycle relies on folate, B6, B12, B2, choline (60% of dietary methyl groups are from choline) and betaine to maintain normal homocysteine levels and general homeostasis of the body.

The terms “hypomethylation” and “hypermethylation” refer to the low or high amount of methyl groups. As we age, gradual DNA hypomethylation occurs (increasing the need for methyl groups) and several studies show that DNA hypomethylation is the main causative factor of defective gene expression.

What is Homocysteine?

Homocysteine is a non-protein amino acid that is produced from methionine, can be recycled back into methionine and converted into cysteine in the methylation cycle. Variants in the MTHFR C677T, MTHFR A1298C, PEMT, and genes like CBS that require higher amounts of B6 can lead to elevated homocysteine due to the higher need for the folate, choline, betaine (beets, spinach quinoa) B12, B6, and other co-factors.

High homocysteine levels have been connected to depression, blood clots, inflammation, macular degeneration, dementia, and cancer.

Homocysteine in Action: The Methylation Cycle Diagram

The methylation cycle diagram gives you a visual on how all of the genes related to folate, B6, B12, B2, choline and betaine are working together for optimal gene expression. This diagram is to serve as a study tool for an in-depth understanding of the methylation cycle section in the Nutrition Genome Report.

Here is where you can see the increased vitamin needs for SNPs that may cause reduced enzymatic function and lead to low levels of folate, B6, B12, betaine, choline and elevated homocysteine.