New clues about whether genes or environment influence our health more

On Nutrition

I’ve previously written about how we can’t disease-proof ourselves by eating and exercising “perfectly.” One, “perfect” is subjective, and two, many other factors contribute to health. Genetics is one factor, social determinants of health (SDoH) — the conditions in the environments where people are born, grow, live, learn, play, work and age — are another. Public health organizations generally group SDoH into five core categories:

Economic stability: This looks at the connection between financial resources and health. It includes factors like steady employment, livable wages, debt and food security (having reliable access to nutritious, affordable food).

Education access and quality: Higher levels of education are strongly linked to better health outcomes and longer life expectancy. This domain focuses on graduating high school, enrollment in higher education, early childhood education and basic literacy.

Healthcare access and quality: This involves whether a person can easily get the medical care they need, covering health insurance status, health literacy (understanding medical information) and proximity to high-quality clinical care.

Neighborhood and built environment: The physical surroundings where a person lives heavily impact daily safety and health risks. Key issues include housing quality, clean air and water, neighborhood violence and access to safe parks or sidewalks for movement.

Social and community context: This centers on relationships and systemic influences. It covers social support systems, community civic participation and the health impacts of facing workplace or systemic discrimination and bias.

It’s been clear for some time that SDoH play a massive role in shaping our health, well-being and overall quality of life. While healthcare access is vital, research shows that medical care only accounts for about 10-20% of modifiable health outcomes. The remaining 80-90% is driven by these social, economic and environmental factors.

A recent study analyzed data from the National Institutes of Health’s All of Us Research Program, which included genetic information, electronic health records and survey responses from participants across the country. The results suggest that SDoH may play an equally important, or even more important, role than genetics in predicting our risk of developing asthma, chronic kidney disease, coronary heart disease, high cholesterol, breast cancer and prostate cancer.

Why? Because when social and systemic factors are inequitable, they create health disparities — preventable differences in health burdens. Addressing SDoH isn’t just about encouraging individuals to make healthy choices — it’s about shifting policies and systems to ensure everyone has the foundational environment required to thrive. It’s about addressing risk factors like smoking, but also loneliness.

To understand how SDoH translate into real-world outcomes, it helps to look at chronic diseases like type 2 diabetes and cardiovascular disease, which are heavily influenced by systemic factors rather than just individual choice. Here are three examples:

1. The interaction of food insecurity and housing stability

Consider two people diagnosed with Type 2 diabetes who receive identical medical care and prescriptions.

• Person A has a stable income and reliable housing with a working kitchen. They live in an area with multiple well-stocked grocery stores and can easily afford and store fresh produce, lean proteins and complex carbohydrates to manage their blood sugar.
• Person B lives in a food desert (an area lacking access to affordable, nutritious food) and relies on food pantries or local convenience stores, where options are mostly shelf-stable, highly processed and carbohydrate-dense. Additionally, they experience housing instability, moving between temporary living situations without consistent access to a refrigerator or stove.

Despite having the same medical care, Person B faces systemic barriers that make diabetes self-care incredibly difficult. This frequently leads to higher HbA1c levels, more frequent emergency room visits for hypo- or hyperglycemia (low or high blood sugar) and a faster progression toward diabetes complications. Research has found that affordable housing programs may help improve diabetes outcomes.

2. Environmental racism and cardiovascular health

It’s well-documented that the built environment — including buildings, parks, roads, sidewalks, transportation and utilities — plays a role in cardiovascular health.

• Low-income neighborhoods and communities of color are statistically more likely to be located near industrial zones, major highways or chemical plants. Chronic exposure to fine particulate matter in the air causes systemic inflammation and vascular damage, directly accelerating the development of atherosclerosis (plaque buildup in the arteries) and increasing the risk of stroke and myocardial infarction (heart attack).
• These same neighborhoods often experience “urban heat island” effects due to a lack of green spaces and tree canopy, combined with high concentrations of concrete. During extreme weather events, residents face higher rates of heat-related cardiovascular stress. When paired with a lack of safe, accessible sidewalks or parks, residents face structural barriers to regular physical activity.

3. The ‘weathering’ effect of systemic discrimination

Chronic exposure to social stressors, such as racism, size stigma or severe economic strain, triggers a prolonged, low-grade biological stress response. Public health researchers refer to this as weathering — the premature biological aging of the body due to the constant wear and tear of high allostatic load (the cumulative burden of chronic stress).

• When someone constantly navigates discriminatory environments or faces the anxiety of financial insecurity, their body frequently releases stress hormones like cortisol and adrenaline. Over time, this can lead to chronic high blood pressure, insulin resistance and immune system dysregulation.
• Consequently, individuals facing high systemic discrimination often develop cardiovascular disease and metabolic conditions years earlier than those who don’t have those same social stressors, regardless of their personal health behaviors.

In each cases, the root cause of the health disparity isn’t a lack of personal willpower or health knowledge. It’s a structural misalignment between standard advice — eat a balanced diet, exercise daily, reduce stress — and the physical, social and economic realities of the environment the person is forced to navigate. The bottom line is that how healthy we are isn’t solely a matter of personal choice. And being in the position to even make personal choices about health behaviors? That’s a privilege.