The following guide explains What is Methylation?
What is Methylation?
The human DNA (deoxyribonucleic acid) is the ‘instruction manual’ containing information needed for the production of proteins in the body. Each portion of the DNA that contains the information needed to produce a particular protein is called a gene.
Nucleotide bases are important components of the DNA and they include cytosine, adenine, guanine, and thymine. The DNA can undergo various changes that ultimately impact cell function such as point mutation, insertion, or deletion.
DNA methylation is a chemical modification of the DNA in which methyl groups are inserted into the DNA. This insertion occurs at the 5th carbon position of cytosine, forming 5-Methyl cytosine.
The process is induced by a family of enzymes called DNA methyltransferases. This modification of the DNA can be passed from parents to offspring.
Why is methylation important?
- It has a significant effect on gene expression and can cause the inactivation of genes in the body, a phenomenon known as ‘gene silencing.
- It helps in maintaining the integrity and stability of the DNA.
- It is required for normal cell multiplication.
- It helps the body to achieve detoxification of harmful chemicals.
- It protects the immune system.
- It helps to improve the function of hormones in the body.
- It is crucial for the normal functioning of the brain cells.
Why is methylation important for detoxification?
The body is constantly exposed to a myriad of toxic substances present in food, water, inhaled air, body care products et cetera. The liver is saddled with the responsibility of removing these substances via a process called detoxification. Detoxification is a crucial process required for balanced emotional and physical well-being. Inefficient detoxification has been linked with diseases such as cancer, Parkinson’s disease, fibromyalgia, and chronic fatigue syndrome.
The by-products released from the methylation reaction include S-adenosyl methionine and homocysteine. Homocysteine is further converted to cysteine, which combines with the amino acids – glutamate and glycine to form glutathione. Glutathione is a potent antioxidant that helps to remove free radicals, toxins, and carcinogens from the body. The role it plays in the detoxification process can not be over-emphasized. Glutathione detoxifies endogenous and exogenous compounds by enhancing their excretion first from the cells and then from the body. It also directly neutralizes free radicals that can damage cell membranes. High levels of glutathione in the body have been linked with longevity and well-being.
Since methylation provides one of the substrates needed for the production of this essential detoxicant, it is highly paramount for detoxification.
What are the causes of abnormal methylation?
- Diet: Studies have shown that diet plays a key role in the process of methylation in the body. Methyl-donor diets are foods rich in folate and B vitamins. They serve as sources for the methyl group inserted into the DNA. Consuming foods low in these nutrients can impair the methylation process in the body.
- Genetics: Recent molecular research has revealed that mutations in the gene responsible for folate metabolism – the MTHFR gene can have detrimental effects on DNA methylation.
- Aging: As people grow older, their genomes undergo a lot of changes and disordered methylation could occur.
- Inflammation: Studies have shown an association between longstanding inflammatory diseases such as ulcerative colitis or hepatitis and exaggerated methylation in the body.
- Smoking: Toxins in cigarette smoke can cause lower vitamin B12 concentrations in the body and this has a negative ripple effect on DNA methylation.
What are the diseases linked with abnormal methylation?
Aberrant methylation in the body could either be hypomethylation or hypermethylation. Both forms are harmful and have been associated with a number of diseases.
An abnormal methylation process is found in almost all forms of cancer. Many mechanisms by which it occurs have been proposed. It has been proposed that disruption of methylation can cause the inactivation of genes that protect a person from cancer such as tumor suppressor genes, leading to cancer. Other studies have also shown that DNA hypomethylation can result in the instability of the chromosomes, leading to cancer.
Other diseases associated with defective methylation include:
- Rheumatoid arthritis
- Systemic lupus erythematosus
- Congenital heart disease
- Multiple sclerosis
- Parkinson’s disease
- Liver disease
How can you improve methylation in your body?
- Dietary modification: Eating diets rich in folate, betaine, and vitamins B2, B6, and B12 can improve methylation in the body. These nutrients provide the much-needed methyl groups for the methylation reaction to occur. Some methyl-donor-rich foods include fish, cauliflower, broccoli, beans, and spinach.
- Zinc supplementation: Research has shown that zinc deficiency leads to DNA hypomethylation. Thus, zinc supplementation can help to improve methylation in the body.
- Smoking cessation: Smoking antagonizes the effect of many nutrients in the body including the B vitamins. It also releases numerous toxins into the body that can trigger a chronic inflammatory state, thereby impairing methylation. Quitting smoking can help correct defective methylation.
- Exercise: Exercise has been shown to significantly impact DNA methylation in many body cells such as heart cells and sperm cells. Regular exercise can improve methylation and slow down the aging process.
What is Methylation? Final Points
- Methylation is a vital body process that is needed for maintaining cellular functions.
- Glutathione, a powerful antioxidant required for detoxification is synthesized using products of methylation.
- Diets poor in vitamins and folate can impede proper methylation by the body.
- Adequate nutritional intake and exercise can improve methylation in the body.
Jin Z, Liu Y. DNA methylation in human diseases. Genes Dis. 2018 Jan 31;5(1):1-8. doi: 10.1016/j.gendis.2018.01.002.
Moore LD, Le T, Fan G. DNA methylation and its basic function. Neuropsychopharmacology. 2013 Jan;38(1):23-38. doi: 10.1038/npp.2012.112.
Nishiyama A, Nakanishi M. Navigating the DNA methylation landscape of cancer. Trends Genet. 2021 Nov;37(11):1012-1027. doi: 10.1016/j.tig.2021.05.002.
Sellami M, Bragazzi N, Prince MS, Denham J, Elrayess M. Regular, Intense Exercise Training as a Healthy Aging Lifestyle Strategy: Preventing DNA Damage, Telomere Shortening and Adverse DNA Methylation Changes Over a Lifetime. Front Genet. 2021 Aug 6;12:652497. doi: 10.3389/fgene.2021.652497.
Suzuki H., Toyota M., Sato H., Sonoda T., Sakauchi F., Mori M. Roles and Causes of Abnormal DNA Methylation in Gastrointestinal Cancers. Asian Pacific Journal of Cancer Prevention, 2006;7: 177-185.