Article about a doctor who claimed to fix a boys fatal genetic disorder that tends to lead to leukemia. I skimmed through most of it to get to the nutrition part. But here's an explanation & below the diet supplements.
each time a cell divides it will either produce the same mutation or it will fix the mutation. I told her that mutation was a normal thing that the body has to contend with each and every day. It isn't until the exposures to chemical toxicities overwhelms our nutritional ability that we end up with such chronic mutations or disease. This process is called epigenetics.Epigenetics is a fascinating process by which the body turns on and off genes through one carbon metabolism. By understanding how to help the body with its epigenetic gene manipulation, a physician can help recover mutations and unfavorable gene sequencing.  This whole process is why my identical twin daughters are slightly different as they get older. Their DNA is 100% identical but through environmental factors, diet, and lifestyle, their DNA sequencing has evolved to allow these slight variations.
My dietary goal is to balance out the methylation process to improve the gene signaling while improving the body's ability to repair and edit the mutated DNA. This was accomplished by switching the patient to a low glycemic, nutrient dense diet with lots of fruits, vegetables, nuts, seeds, berries, and legumes; real actual food with the least processing. Next we supplemented with methylcobalamin (methyl B12 lozenges), folate, and B6 supplements. Each of these helps regulate the homocysteine pathway which regulates gene sequencing. This one carbon metabolism of methylation normally is fed by a rich diet of beans, greens and fermented foods. 
Funny, ever since I first heard of methylation, the definition always included something about methyl donors. And methyl donors are your sulfur containing amino acids. So I'd been under the impression that it was 'all about sulfur'. But B vitamins seem to be what most are concerned about due to the homocysteine pathway.
Also, I'd think you'd want to promote the recycling of tissues, in which the body would hopefully break down bad or damaged tissues. And intermittent fasting is the way. We aren't supposed to have plenty to eat all the time & it's when we go hungry, that this happens.
Paper about Genetics researchers from Taiwan's National Central University findings that over a third of herbal medicines used in Traditional Chinese Medicine - and nearly all leading therapeutic herbs - alter our genes or alter enzymes that alter our genetic material. http://www.greenmedinfo.com/blog/herbal-medicine-alters-genes-cell-mitosis-and-epigenome.
[50%] of them promote what is called chromatin condensation. Chromatin is the complex of DNA and protein material that our cells' nucleus is made of. Through the histone enzymes, chromatin will bind up and prepare for cell division, allowing a copy of our DNA to be made during mitosis.
Chromatin condensation occurs during the cell's reproductive cycle – as cells divide. During the interphase step the chromatin is loosely mixed, and then during the prophase step the chromatin will condense and the chromosomes will become visible to microscopic observation. This condensed state continues one through the next stages of mitosis until the cell successfully divides. The histones organize the DNA during this chromatin condensation process. The relates directly to DNA repair.
the researchers found a correlation between traditional Chinese medicine hot or cold characteristics as they processed the analysis of the herbs. They also found that some of the alteration occurred through a process called methylation, which occurs as methyl groups are displaced and replaced in order to neutralize radicals.
The fact that so many herbal medicines interact with the histones of the body's cells is critical to understanding the importance of the herbal medicine from both a macro and microscopic view.
This research confirms a study published in 2011 that found nearly 30% of those herbal medicines tested alter the miRNA of cells, and modify our genetic epigenome.
Also' "an enzyme called MTHFR (5,10-methylenetetrahydrofolate reductase) to convert folic acid and food folate into 5-methylenetetrahydrofolate." Which is the the form involved in epigenetic changes/DNA Repair &/or whatnot. and 'active thyroid hormone is needed to support MTHFR function'
"It hopefully goes without saying that oxidative stress from environmental pollutants, food allergens, poor sleep, and limited relaxation all increase the demand to the corrective efforts of methylation. A clean diet, home, body, and mind are a part of this package. There is rarely a one pill solution, pharmaceutical or nutriceutical."