There have been numerous advances in epigenetic studies – the science of how genes are altered in organisms like us via environmental changes instead of altering the genetic code (DNA) itself.
While our DNA genome is hard-coded, through a process called methylation, our genes can be signaled to turn on or off based on choices we make like our diet, level of exercise, exposure to stress (or lack thereof).
In the latest confirmation that we have much more control over our intelligence and health than assumed as little as 25 years ago, we now know that we can even turn on stem cells that signal neurons in our brains to work – even as we age, and most of the plant is suffering from cognitive decline, and issues like Alzheimer’s Parkinson’s and various forms of dementia.
According to Statista, In 2018, it was estimated that around 50 million people suffered from dementia globally, costing around 1 trillion U.S. dollars a year in health care costs. 
Specifically, scientists are studying how the transcriptional and epigenetic mechanisms responsible for quiescent neural stem cells (NSC) are maintained and activated during aging. 
Quiescent neural stem cells in the adult brain are regenerative cells that can be activated therapeutically to repair cellular damage. It is becoming apparent that quiescent NSCs exhibit heterogeneity in their propensity for activation and in the progeny that they generate. 
In plain English, this means that previously it was thought that “arrested” neural stem cells could not be regenerated. With “therapeutic” measures they can be. From an epigenetic standpoint this means that practices likes meditation, diet, and reducing stress could do more than just boost your mood or help you look better when you look in the mirror – -these types of actions could actually be turning “on” your neural stem cells and stalling neurodegenerative disease.
In fact, a recently published article in the journal, Frontiers, suggested that the brain-protecting effects of meditation are becoming more clear.
The mechanisms pertaining to normal (brain) aging, specifically focusing on telomeres, inflammation, stress regulation, and macroscopic brain anatomy are little understood, but studies suggesting that the stem cells themselves can be altered are monumentally important. 
This insinuates that ANY cell in the body can be altered epigenetically. Why? Stem cells have the potential to develop into many different types of cells in the body. They serve as a repair system for the body. If stem cells can be regenerated, it follows that the entire body and mind can be too.
 Dementia treatment cost forecast globally 2018-2030. (n.d.). Retrieved from https://www.statista.com/statistics/471323/global-dementia-economic-impact-forecast/
Activating dormant neural stem cells in the adult and aged brain | Carney Institute for Brain Science. (n.d.). Retrieved from https://www.brown.edu/carney/research-project/activating-dormant-neural-stem-cells-adult-and-aged-brain
 Promising Links between Meditation and Reduced (Brain) Aging: An Attempt to Bridge Some Gaps between the Alleged Fountain of Youth and the Youth of the Field. (n.d.). Retrieved from https://www.frontiersin.org/articles/10.3389/fpsyg.2017.00860/full