Effects of trauma and harm passed on for generations
The notion that genes dictate our destiny has been solidly debunked in favor of epigenetics, the study of external or internal mechanisms that switch genes on and off. Exciting new research shows epigenetic memory can span multiple generations.
The Centers for Disease Control (CDC) estimates that genetics are responsible for a mere 10 percent of disease, while the remaining 90 percent is due to environmental variables.
Consider these research findings:
In rats, maternal exposure to endocrine-disrupting chemicals caused infertility in male offspring that was passed down to 90 percent of males in four subsequent generations.
Adaptations to traumatic experiences can also be passed down multiple generations as a way to inform offspring about methods for survival.
For example, mice who learned to fear a scent associated with a negative experience passed the response down two generations, despite the offspring never having experienced the same situation.
A similar transfer of responses has been observed in humans:
Exposure to starvation during pregnancy is associated with poor health outcomes for offspring such as:
- Lower self-reported mental health and quality of life
- Major mood disorders
- Antisocial personality disorders
- Decreased intracranial volume
- Congenital abnormalities of the central nervous system
- Enhanced incidence of cardiovascular disease
Descendants of people who survived the Holocaust show abnormal stress hormone profiles, in particular low cortisol production. Because of altered stress response, children of Holocaust survivors can be at increased risk for PTSD, depression, and anxiety.
Children of women exposed to intimate partner violence during pregnancy have higher predisposition to mental illness, behavioral problems, and psychological abnormalities due to transgenerational epigenetic programming of genes acting in the hypothalamic-pituitary-adrenal axis (HPA axis), a complex communication pathway between glands involved in our stress response.
Classic genetic theory states that genetic change occurs over a time scale of hundreds to millions of years.
Epigenetics explains how our lifestyle, diet, environment, and experiences affect the expression of our genes over multiple generations, but it does not account for actual changes to our genetic code.
How do genetics and epigenetics relate?
Via epigenetics our genes can be influenced by factors such as:
- Sleep habits
- Where you live
- Who you interact with
- Exercise habits
- Environmental toxins
- Heavy metals
- Stress level
- Social support (or lack of it)
- Method of birth (cesarean vs. vaginal)
- And more
We inherit one variant of each gene from each parent. Epigenetics can turn off one of these two gene variants (this is called “imprinting”).
This can result in a negative health outcome if the other, still-active variant is defective or increases our susceptibility to toxins or infections.
The cumulative impacts of our lives on our genes
Related to epigenetics is the exposome, the cumulative measure of all the exposures of an individual in a lifetime — starting at conception — and how they relate to our health. Some consider the exposome the environmental equivalent of the human genome.
The exposome is divided into three overlapping categories:
The environment inside our bodies that affects our cells:
- Hormones and other cell messengers
- Oxidative stress (excess highly reactive and damaging molecules)
- Lipid peroxidation (damage to cell membranes and other molecules containing fats)
- Body shape
- Gut microbiota
- Biochemical stress
The external environment to which we expose our bodies:
- Occupational factors
- Pathogens and toxins
- Medical interventions
The general external environment, including broader sociocultural and ecological factors:
- Socioeconomic status
- Geopolitical factors
- Psychological stress
- Education status
- Urban or rural residence
Using epigenetics to positively impact the future
Epigenetic processes are natural and essential to many bodily functions. But if they go wrong they can negatively impacts not only our health but the health of our children. Researchers feel the ability for these changes to be passed down has significant implications regarding evolutionary biology and disease causation.
There are factors we have no control over such as certain environmental toxins, method of birth, and exposure to some level of stress. The good news is we can affect change in many areas that can powerfully affect our epigenetics:
- Anti-inflammatory diet
- Daily exercise
- Stress-relief activities
- Good sleep habits
- Who we interact with
- Antioxidant status
- Not smoking
- Social support
- Addressing food intolerances
- Mediating autoimmunity
Functional medicine offers many avenues to support healthy epigenetic expression. If you seek ways to help your body express its genes in the best ways possible, contact my office for help.