This article has GREAT content but a severe drawback is that an extremely high level of understanding of genetics and biology is required to fully comprehend it without extensive use of the dictionary. In the first two sections I counted 17 words just for which off the top of my head I could not give an accurate definition. I commented on the article that if you are writing to communicate to the general public and not just biologists you would be well advised to either define the technical words used or keep the target audience in mind and phrase accordingly.
So here’s the synopsis.
The genes you inherit from your parents acount for only 10-16% (depending on whom you quote) of your health outcomes. Whether diet, lifestyle choices, environmental factors and toxins “turn on” or cause those genes to be expressed, is 84-90% of the deal.
…the Centers for Disease Control (CDC) states that genetics account for only 10% of disease, with the remaining 90% owing to environmental variables. An article published in the Public Library of Science One (PLoS One) entitled “Genetic factors are not the major causes of chronic diseases” echoes these claims, citing that chronic disease is only 16.4% genetic, and 84.6% environmental. These concepts make sense in light of research on the exposome. (Definition: The exposome encompasses the totality of human environmental (i.e. non-genetic) exposures from conception onwards, complementing the genome, first proposed in 2005 by a cancer epidemiologist. The cumulative measure of all the environmental insults an individual incurs during their life course that determines susceptibility to disease.)
For instance some heart drugs have been found to cause gene changes that lead to lupus.
Genes Might Load the Gun But Environment Pulls the Trigger
Pharmaceuticals, however, are not the only agents that can induce epigenetic disturbances. Whether you were born via vaginal birth or Cesarean section, breastfed or bottle-fed, raised with a pet in the house, or infected with certain childhood illnesses all influence your epigenetic expression. Whether you are sedentary, pray, smoke, mediate, do yoga, have an extensive network of social support or are alienated from your community—all of your lifestyle choices play into your risk for disease operating through mechanisms of epigenetics.
In delineating the totality of exposures to which an individual is subjected over their lifetime, the exposome can be subdivided into three overlapping and intertwined domains. One segment of the exposome called the internal environment is comprised of processes innate to the body which impinge on the cellular environment. This encompasses hormones and other cellular messengers, oxidative stress, inflammation, lipid peroxidation, bodily morphology, the gut microbiota, aging and biochemical stress.
Another portion of the exposome, the specific external environment, consists of exposures including pathogens, radiation, chemical contaminants and pollutants, and medical interventions, as well as dietary, lifestyle, and occupational elements.
At an even broader sociocultural and ecological level is the segment of the exposome called the general external environment, which may circumscribe factors such as psychological stress, socioeconomic status, geopolitical variables, educational attainment, urban or rural residence, and climate.
Transgenerational Inheritance of Epigenetic Change: Endocrine Disruptors Trigger Infertility in Future Generations
Scientists formerly speculated that epigenetic changes disappear with each new generation during the formation of sperm and ovum, and after fertilization. This theory was first challenged by research published in the journal Science which demonstrated that transient exposure of pregnant rats to the insecticide methoxychlor, an estrogenic compound, or the fungicide vinclozolin, an antiandrogenic compound, resulted in increased incidence of male infertility and decreased sperm production and viability in 90% of the males of four subsequent generations that were tracked.
Most notably, these reproductive effects were associated with derangements in DNA methylation patterns in the germ (sperm and eggs) line, suggesting that epigenetic changes are passed on to future generations. The authors concluded, “The ability of an environmental factor (for example, endocrine disruptor) to reprogram the germ line and to promote a transgenerational disease state has significant implications for evolutionary biology and disease etiology”. This may suggest that the endocrine-disrupting, fragrance-laden personal care products and commercial cleaning supplies to which we are all exposed may trigger fertility problems in multiple future generations.
Reactions to Toxins and Environmental Stressors Passed to Next Generation
…The study suggests that certain characteristics of the parental sensory environment experienced before conception can remodel the sensory nervous system and neuroanatomy in subsequently conceived generations…
…exposures to certain stressors such as starvation during the gestational period are associated with poor health outcomes for offspring. Women who undergo famine before conception of her offspring have been demonstrated to give birth to children with lower self-reported mental health and quality of life, for example…