Epigenetic mechanisms indirectly encoded in the genome change gene activity in response to lifestyle and environmental factors, from intrauterine development to death. Having intensively developed over the past 30 years, epigenetics discloses the molecular epigenetic basis of the mechanisms of the body’s response to environmental and lifestyle factors. The body’s metabolic changes that occur in the early critical period under the influence of harmful behavioral and environmental factors and result in chronic non-communicable diseases that are the leading causes of death may be corrected by lifestyle modifications in later life periods. Thus, today, epigenetics provides a fundamental basis and offers hope for improvement in health and increases in life expectancy for mankind through preventive measures and hygiene. © 2019, Media Sphera Publishing Group. All rights reserved.