What began during the mid-twentieth century as broad research focused on combining genetics and developmental biology has evolved into the field we currently refer to as epigenetics.
The idea that environmental factors can trigger epigenetic changes reflected at different stages throughout a person’s life and even in later generations is controversial, as scientific convention states that genes contained in DNA are the only way to transmit biological information between generations. However, new scientific evidence demonstrates that our genes are modified by the environment all the time, through chemical tags that attach themselves to our DNA, switching genes on and off.
New and ongoing research is providing an increasing amount of information regarding the role of epigenetics in a variety of human disorders including various cancers, mental retardation associated disorders, immune disorders, neuropsychiatric disorders and pediatric disorders.
The growing understanding that both the environment and individual lifestyle can interact directly with the genome to influence epigenetic change is influencing our understanding of diseases and their treatments.
What is Epigenetics?
The term epigenetics was derived from the Greek word “epigenesis” which originally described the influence of genetic processes on development. It can be defined as the study of changes in gene expression - the mechanisms that switch genes on or off - which in turn affect how cells use the DNA's instructions. These changes in gene expression can be inherited, but contrary to genetic mutations, they don’t involve changes to the underlying DNA sequence. In scientific terms, we talk about a change in phenotype without a change in genotype.
Epigenetic changes constitute a natural phenomenon and they are submitted to the influence of several factors including our age, our environment, our diet, our lifestyle, etc. Epigenetic modifications can manifest in minor ways but they can also have more deleterious effects resulting in diseases.
Epigenetics is involved in every aspect of life and such heritable, reversible changes affect the way we live and also, our future generations. Recent studies suggest that some of these tags might somehow be passed through generations, meaning our environment could have and impact on our children’s health.
Although still in its infancy, the theory of epigenetic inheritance is gaining scientific support. For example, evidence from human epidemiological studies demonstrated that prenatal and early postnatal environmental factors influence the adult risk of developing various chronic diseases and behavioral disorders.
Other recent research, such as the one conducted at New York’s Mount Sinai hospital and led by Rachel Yehuda also revealed that one person’s life experience can affect subsequent generations. In her landmark study, Yehuda and her team provided evidence that genetic changes stemming from the trauma suffered by Holocaust survivors are capable of being passed on to their children. This is the first demonstration of an association of preconception parental trauma with epigenetic alterations, providing potential insight into how severe psychophysiological trauma can have intergenerational effects.
Epigenetics and Diet
It has now become widely accepted that diet alters our genes, but we are now discovering that parents’ eating habits can influence the health of future generations. Our poor dietary choices are encoded into our gut bacteria, our genes, and are passed to our offspring.
There is evidence that children inherit their microbiome from their
mother. If a mother has an imbalance of gut bacteria (dysbiosis), she will pass the imbalance onto her child. This developmental dysbiosis leaves the offspring’s immune system poorly prepared to fight off infections and predisposes the child to autoimmune and allergic diseases.
It’s a well known fact by most people that mothers need to get adequate amounts of folate (or vitamin B9) in their diet in order to prevent miscarriages and birth defects, but we are now finding out that even the father’s diet plays a role in his child’s future health. A research study led by Sarah Kimmins at McGill University in Montreal showed that the father’s folate levels may be just as important to the development and health of their offspring as are those of the mother.
According to Dr. Lambrot, one of the researchers involved in the Kimmins’ group: “We were very surprised to see that there was an almost 30 percent increase in birth defects in the litters sired by fathers whose levels of folates were insufficient.” The research shows that there are regions of the sperm epigenome that are sensitive to life experience, and particularly to diet.
The increased knowledge and technologies in epigenetics over the last ten years allow us to better understand the interplay between epigenetic change, gene regulation, and human diseases. As the role of epigenetics in health and disease is becoming ever clearer, this field of study will eventually supplant the current, outdated medical paradigm.
As a result of these findings, we're now finally seeing science altering its course to investigate the power of optimal nutrition to improve health and prevent chronic disease. However, this shift in paradigm from the idea that our genes predetermined our health to the acknowledgement that each individual wields over their own health by altering their diet and lifestyle is still received by some with a certain level of resistance and skepticism.
As John Maynard Keynes once said: ‘The difficulty lies not so much in developing new ideas as in escaping from old ones."