The Short Answer

Research shows that traumatic experiences and environmental stressors can alter gene expression in ways that persist across multiple generations, a process called epigenetics. These changes don’t alter your DNA itself, but they can increase vulnerability to autoimmune conditions, including Hashimoto’s low thyroid, mood disorders, and chronic illness. The good news: lifestyle factors like diet, exercise, and stress management can help restore healthy gene expression and reduce this inherited risk.

Understanding Epigenetics and Inherited Stress Responses

Traumas experienced by your grandparents or great-grandparents could be affecting your health today. New research demonstrates that “epigenetic memory” can be passed down through as many as four generations, a sobering reminder that our genes aren’t our destiny.

Epigenetics is the study of factors that switch genes on and off without changing the underlying DNA code. These factors have been linked to dysfunctions in learning and memory, autoimmunity, cardiovascular disease, and cancer.

Here’s what’s striking: the CDC estimates that genetics account for only 10 percent of disease risk, while epigenetics, driven by environment and experience, accounts for the remaining 90 percent. This means the choices we make and the stressors we face have profound power over how our genes express themselves.

How Trauma Gets Passed Down Across Generations

The evidence is compelling. Studies show:

• In animal models: Pregnant rats exposed to reproductive-disrupting chemicals passed male infertility down through four subsequent generations, even when offspring never encountered the same chemicals.
• Fear conditioning: Mice exposed to a specific scent during trauma passed their learned fear response to two generations of descendants who never experienced the original threat.
• In humans: Starvation during pregnancy is associated with poor health outcomes in offspring, including mood disorders, cardiovascular disease, hypertension, and increased risk of obesity.
• Holocaust survivors and their descendants: Show abnormal stress hormone profiles and low cortisol production, increasing vulnerability to PTSD, depression, and anxiety.
• Prenatal violence exposure: Children born to women exposed to domestic partner violence during pregnancy face elevated risk for mental illness, behavioral problems, and psychological abnormalities.

Our internal responses to trauma appear to function as a survival adaptation, one that can persist long after the original threat is gone.

Environmental and Lifestyle Factors That Shape Gene Expression

Epigenetics works through numerous pathways. Your genes can be turned on or off by:

• Diet and food intolerances
• Sleep quality and quantity
• Exercise habits
• Stress levels and chronic tension
• Social support (or isolation)
• Environmental toxins and heavy metals
• Smoking and substance use
• Birth method (cesarean vs. vaginal delivery)
• Medications and supplements
• Who you regularly interact with

Broader sociocultural factors also play a role: socioeconomic status, educational background, geopolitical stress, urban versus rural living, and climate all influence epigenetic expression.

You inherit one gene variant from each parent. Epigenetics determines whether these genes are activated or silenced. If one inherited variant carries risk for autoimmune conditions, such as Hashimoto’s low thyroid, epigenetic factors can either amplify or reduce that risk.

Reclaiming Your Epigenetic Health

While you cannot change your ancestors’ experiences or fully control environmental toxins, you have significant power over the factors that influence healthy gene expression:

• Anti-inflammatory eating patterns reduce systemic inflammation
• Daily movement and exercise upregulate protective genes
• Stress-relief practices normalize cortisol and immune function
• Consistent, quality sleep supports immune regulation and repair
• Meaningful social connection buffers against chronic stress
• Optimized antioxidant intake protects against oxidative damage
• Avoiding smoking and excess alcohol prevents epigenetic silencing of protective genes
• Addressing food sensitivities reduces immune activation
• Mediating autoimmune responses through targeted nutrition and lifestyle

These same factors form the foundation of managing autoimmune conditions, including Hashimoto’s low thyroid. Functional medicine provides evidence-based methods to support optimal gene expression and interrupt inherited patterns of illness.

Contact RedRiver Health and Wellness to work with a functional medicine doctor who understands how generational patterns affect autoimmune conditions and can help you restore healthy gene expression.