Yoga and Epigenetics

Numer­ous research works over the past few decades have shown how Yoga and med­i­ta­tion pos­i­tive­ly impact well-being and reduce stress. Recent­ly, the mol­e­c­u­lar mech­a­nisms under­ly­ing the ben­e­fits of Yog­ic prac­tices have begun to be inves­ti­gat­ed. It is now thought that Yog­ic prac­tices influ­ence the body through epi­ge­net­ic mod­i­fi­ca­tions. To under­stand the research in a sim­ple way, let us first gain an overview of key con­cepts in epi­ge­net­ics.

Every sin­gle cell in our body con­tains close to 2 metres of DNA, which con­tain our genet­ic infor­ma­tion. A gene is a seg­ment of the DNA that holds instruc­tions for the pro­duc­tion of a cell’s pro­tein. The genome is the com­plete set of DNA, includ­ing all of its genes. Each genome con­tains all the infor­ma­tion need­ed to build and main­tain the organ­ism. Since the DNA is very long, it is pack­aged togeth­er with pro­teins known as his­tones. The DNA wrapped around his­tones resem­bles beads on a string. This DNA-his­tone com­plex is called chro­matin. The DNA and his­tones can be tagged by tiny chem­i­cals which mod­i­fy gene expres­sion, by turn­ing them either “on” or “off”.

The struc­ture of DNA shows how the DNA is pack­aged togeth­er with pro­teins known as his­tones, resem­bling beads on a string. The DNA and his­tones can be tagged by chem­i­cals that mod­i­fy gene expres­sion

Genes are expressed when they are read and tran­scribed into RNA. The RNA is then trans­lat­ed into pro­teins, which deter­mine a cell’s char­ac­ter­is­tics and func­tion. Some of the chem­i­cal tags, such as methyl groups, inhib­it or turn “off” gene expres­sion, by caus­ing the DNA to coil more tight­ly, mak­ing the genes inac­ces­si­ble for tran­scrip­tion. This process is termed as DNA methy­la­tion. Some chem­i­cal tags enhance gene expres­sion by unwind­ing the DNA, mak­ing it eas­i­er to tran­scribe and thus increas­ing the pro­duc­tion of the asso­ci­at­ed pro­tein. Acetyl groups are exam­ples of chem­i­cals that turn “on” the genes. Epi­ge­net­ics (‘Epi’ mean­ing ‘above’) is the study of such mod­i­fi­ca­tions made on the genes, with­out chang­ing the DNA sequence itself.

Chem­i­cal tags such as methyl groups turn “off” the gene and inhib­it gene expres­sion. Some chem­i­cal tags such as acetyl groups turn “on” the gene and enhance gene expres­sion. Such mod­i­fi­ca­tions are influ­enced by our diet, lifestyle, social sup­port sys­tems and the envi­ron­ment.

The epigenome is the key link between the genes and the envi­ron­ment. The chem­i­cal tags that mod­i­fy gene expres­sion are influ­enced by fac­tors like diet, sleep, edu­ca­tion, exer­cise, lifestyle, social sup­port and expo­sure to chem­i­cals. The result­ing epi­ge­net­ic changes could affect cel­lu­lar aging and dis­ease pro­gres­sion. How­ev­er, epi­ge­net­ic changes are not per­ma­nent and they may be changed in the long run via a bal­anced lifestyle, a healthy diet and avoid­ing expo­sure to phys­i­cal and men­tal tox­ins. The field of epi­ge­net­ics explains, using mod­ern sci­en­tif­ic frame­works, the prin­ci­ples that gov­ern Indi­an sys­tems of health and longevi­ty such as Ayurve­da and Yoga. The sci­en­tif­ic com­mu­ni­ty has tak­en a lot of inter­est in inves­ti­gat­ing the epi­ge­net­ic changes in human beings due to a whole­some lifestyle, mind­ful­ness inter­ven­tions and Yog­ic prac­tices.

As many stud­ies have con­sis­tent­ly demon­strat­ed, the prac­tice of Yoga and med­i­ta­tion sig­nif­i­cant­ly reduces stress and stress-induced inflam­ma­tion. Stress-induced inflam­ma­tion com­pro­mis­es the immune sys­tem and is also thought to be the cause of pro­gres­sion of chron­ic and degen­er­a­tive dis­eases. Inflam­ma­tion induces oxida­tive stress (due to an excess of reac­tive oxy­gen species), cel­lu­lar death, aging and sys­temic tis­sue degen­er­a­tion [1].

Researchers from Italy have done a sys­tem­at­ic review of lat­est research on epi­ge­net­ic and mol­e­c­u­lar mech­a­nisms under­ling Yoga and oth­er mind-body prac­tices in the East­ern tra­di­tions [2]. Yoga was shown to reduce reac­tive oxy­gen species (ROS) lev­els, which is respon­si­ble for inflam­ma­tion and accel­er­at­ed aging.

Some researchers have dis­cussed the idea that mind­ful­ness prac­tices influ­ence the body through epi­ge­net­ic mech­a­nisms that reg­u­late gene expres­sion. Sev­er­al stud­ies involv­ing Pranaya­ma, Sudar­shan Kriya and Kir­tan Kriya found tran­scrip­tion­al changes in path­ways involved in oxida­tive stress, cell death, aging and immune response.

In a 2016 study, which was the first of its kind, DNA methy­la­tion lev­els of immune func­tion relat­ed genes were stud­ied in chron­i­cal­ly dis­tressed women prac­tic­ing Yoga [3]. The study showed that Yoga was asso­ci­at­ed with reduced methy­la­tion of the tumour necro­sis fac­tor gene, which is a gene that codes for a pro-inflam­ma­to­ry cytokine.

A recent study has inves­ti­gat­ed the epi­ge­net­ic changes fol­low­ing a sin­gle day of intense med­i­ta­tion for 8 hours [4]. When the methy­la­tion pro­files were observed after 8 hours of prac­tice, med­i­ta­tors showed 61 Dif­fer­en­tial­ly Methy­lat­ed Sites. The methy­la­tion occurred in genes involved in the immune response and inflammation,meaning that the expres­sion of these genes were inhib­it­ed.

Var­i­ous types of med­i­ta­tion like Tran­scen­den­tal Med­i­ta­tion, Sudar­shan Kriya and Kir­tan Kriya have been wide­ly stud­ied at a mol­e­c­u­lar lev­el. They influ­ence the lev­els of hor­mones and neu­ro­trans­mit­ters (chem­i­cal mes­sen­gers of the ner­vous sys­tem) that are affect­ed by stress, such as:

1. cor­ti­sol — a stress hor­mone, involved in the “fight or flight” response

2. epi­neph­rine — also known as adren­a­line, a hor­mone and neu­ro­trans­mit­ter that is released dur­ing acute stress

3. nor­ep­i­neph­rine — anoth­er stress hor­mone released dur­ing acute stress

4. sero­tonin — a hor­mone that sta­bi­lizes mood and feel­ing of well-being and assists with sleep­ing and diges­tion)

5. mela­tonin — a hor­mone released by the pineal gland at night and con­trols the sleep-wake cycle

6. GABA — a neu­ro­trans­mit­ter which is a nat­ur­al relax­ant of the brain and ner­vous sys­tem

The var­i­ous types of med­i­ta­tion also stim­u­late anti-inflam­ma­to­ry cytokines and endor­phins (chem­i­cal that acts as a nat­ur­al pain reliev­er). BDNF (Brain derived neu­rotroph­ic fac­tor), which is a key mol­e­cule involved in plas­tic changes relat­ed to learn­ing and mem­o­ry, has been found to increase after Yog­ic prac­tice, in both healthy and depressed peo­ple. Such stud­ies indi­cate that Yoga has the poten­tial to coun­ter­act neu­rode­gen­er­a­tive process­es due to stress by slow­ing down cel­lu­lar aging and pre­serv­ing neu­ro­plas­tic­i­ty in the brain.

It has long been known that mind­ful­ness and Yog­ic prac­tices enhance our well-being by pro­duc­ing a state of phys­i­cal relax­ation and inner silence. The mol­e­c­u­lar and epi­ge­net­ic mech­a­nisms are now being unrav­eled through the sophis­ti­cat­ed research instru­ments and tech­nol­o­gy cre­at­ed by mod­ern sci­ence. Going by the trends, such a nov­el research field cer­tain­ly appears to have a lot of scope. The insights from such research efforts would not only fur­ther the under­stand­ing of Yog­ic sci­ence but also pro­vide pre­cise infor­ma­tion on the appli­ca­tion of Yoga for ther­a­peu­tic pur­pos­es.

Ref­er­ences

[1] Han­ni­bal, K. E., & Bish­op, M. D. (2014). Chron­ic stress, cor­ti­sol dys­func­tion, and pain: a psy­choneu­roen­docrine ratio­nale for stress man­age­ment in pain reha­bil­i­ta­tion. Phys­i­cal ther­a­py, 94(12), 1816–1825.

[2] Ven­dit­ti, S., Ver­done, L., Reale, A., Vetri­ani, V., Caser­ta, M., & Zampieri, M. (2020). Mol­e­cules of silence: Effects of med­i­ta­tion on gene expres­sion and epi­ge­net­ics. Fron­tiers in psy­chol­o­gy, 11, 1767.

[3] Harkess, K. N., Ryan, J., Delfab­bro, P. H., & Cohen-Woods, S. (2016). Pre­lim­i­nary indi­ca­tions of the effect of a brief yoga inter­ven­tion on mark­ers of inflam­ma­tion and DNA methy­la­tion in chron­i­cal­ly stressed women. Trans­la­tion­al psy­chi­a­try, 6(11), e965-e965.

[4] Chaix, R., Fag­ny, M., Cosin-Tomás, M., Alvarez-López, M., Lemee, L., Reg­nault, B., … & Kali­man, P. (2020). Dif­fer­en­tial DNA methy­la­tion in expe­ri­enced med­i­ta­tors after an inten­sive day of mind­ful­ness-based prac­tice: Impli­ca­tions for immune-relat­ed path­ways. Brain, behav­ior, and immu­ni­ty, 84, 36–44.