USC researchers offer insights on how the intersection of modern diets, climate, and food systems is increasing inflammation

The link between highly processed modern-day diets and inflammation-related chronic diseases (e.g., cancer, diabetes, heart disease, Alzheimer’s, poor mental health) has been well-established. But what other factors influence the systemic inflammation and rising rates of chronic diseases experienced by industrialized nations?

USC researchers* recently reviewed the existing literature on diet-induced inflammation, climate change, and food systems – finding numerous scientific papers focusing on each of these areas but very few that looked at their overlap. With nutrition epidemiologist and inflammation expert James Hébert taking the lead, the team examined the intersection of these three factors – along with their collective impacts on health – publishing their insights in Advances in Nutrition.

“Human activities have contributed to large shifts in the global climate, with far-reaching impacts on ecosystems, societies and human health,” says Hébert, who is a Health Sciences Distinguished Professor in the Arnold School of Public Health’s Department of Epidemiology and Biostatistics. “Modern food systems, which are designed to produce convenience foods that tend to have high inflammatory potential, exacerbate environmental degradation and shape the interwoven challenges of climate, nutrition and health.”

These shifts stem from the collective activities people have engaged in since the industrial revolution. The food environment has transitioned from traditional production and delivery methods (e.g., small farms and local markets) to industrial-scale agriculture (e.g., use of synthetic fertilizers, increased reliance on feed lots and antibiotics, high levels of food processing, microplastics entailed in production and packaging) and elaborate distribution systems – all of which impact our environmental footprint and contribute to climate change. In turn, the resulting global warming and associated extreme weather (e.g. droughts, floods) is expected to lead to long-term declines in crop yields due to reduced photosynthesis efficiency, faster evaporation, and increased water absorption by plants.

“In the past three decades, extreme weather has worsened worldwide in parallel with poor diets and inflammation-related health problems,” says Geoff Scott, an expert in aquatic ecotoxicology and the chair of the Arnold School’s Department of Environmental Health Sciences. “The global climate crisis has led to a decline in biodiversity while concurrently amplifying environmental stressors with significant implications for human health. Of particular concern are the climate change effects on soil health, which affects not only agriculture but also natural ecosystems.”

Declines in biodiversity have been exacerbated by the increased market share of ultra-processed foods, which dominate U.S. and global food supplies and rely on industrial formulations rather than the nutrient-dense plants grown using low-impact methods on local farms. Climate events (e.g., floods, droughts, hurricanes) further impact the production and availability of nutritious food by influencing soil fertility, erosion, and contamination as well as reduced plant growth and resilience in the face of extreme weather.

Coastal ecosystems, which are home to more than half the world’s population, face their own unique challenges, such as the climate-induced increase in harmful algal blooms and antibiotic-resistant Vibrio bacteria, which may affect ecosystem services such as seafood provisioning and recreation activities. Further offshore, major ocean regions have been oxygen-starved and artificially nutrient-enriched – leading to dead zones, including the degradation of coral reefs and productive fishery grounds.

To address these challenges, the authors propose a multi-faceted approach encompassing individual behavioral changes, policy interventions, and collaborative initiatives across various sectors. For example, government subsidies that are currently propping up the production of ultra-processed foods should be redirected to support nutrient-dense, plant-based options that are anti-inflammatory and less environmentally damaging. Health insurance programs and other services could promote the consumption of whole foods in their natural forms through incentives and other creative measures. A cultural and clinical shift to treating food as a prescription for addressing chronic disease conditions would go a long way in supporting health as well as environmental recovery through local farming and other restorative practices.

“The intricate relationship between individual behavior, environmental influences, and broader systemic factors shapes our understanding of health, well-being, and sustainability,” the authors write. “These interactions have cascading effects on human and environmental health, and we must take proactive steps forward to protect both.”  

*Authors include James Hébert (Epidemiology and Biostatistics), Richard Holmberg (George Washginton University), Morgan Boncyk (Health Promotion, Education, and Behavior) , Geoffrey Scott (Environmental Health Sciences), Angela Murphy (School of Medicine), and Lorne Hofseth (College of Pharmacy).