Different genes are turned on and off for our cells to specialise into different organs (e.g., Skin, Heart, Brain, etc.). Therefore it is critical to regulate DNA for adaptability and differentiation of our cells.
Vit-B3 helps activate proteins called Sirtuins, which wrap DNA tightly and prevent transcription of certain genes (the first step to express a gene).
Vit-B9 and Vit-B12 help provide Carbon molecules and CH₃ that can bind to DNA to prevent transcription of certain genes.
Dysregulated DNA transcription is a hallmark of Cancer development and uncontrolled gene expression in certain cells.