Climate Change Alters Gene–Diet Interactions: Nutrigenomics, Rising CO₂, and the Future of Human Health

            Climate change is widely discussed in terms of rising temperatures, extreme weather events, and ecosystem disruption. Yet one of its most profound and least visible consequences lies at the molecular interface between food and human biology. As atmospheric carbon dioxide (CO₂) levels rise and climate stress intensifies, the nutritional composition of staple crops is changing in ways that directly influence how human genes function. These changes are not merely dietary concerns; they are genomic, immunological, metabolic, and intergenerational in nature.

Despite growing evidence that climate change is reducing the micronutrient and protein content of major food crops, the biological consequences of these shifts remain underrepresented in climate and health discourse. This article addresses that gap by integrating climate science, crop physiology, nutrigenomics, epigenetics, microbiome research, and public health. It argues that climate change is silently reshaping gene–diet interactions, with particularly severe implications for climate-vulnerable populations such as those in India.

Climate Change and the Transformation of Crop Nutrition

Rising Atmospheric CO₂ and Plant Metabolism

Since the pre-industrial era, atmospheric CO₂ concentrations have increased from approximately 280 ppm to over 420 ppm. Elevated CO₂ enhances photosynthesis in many crops, especially C₃ plants such as rice and wheat. While this can increase yields under controlled conditions, it also alters plant biochemistry in ways that compromise nutritional quality. Higher CO₂ accelerates carbohydrate production, leading to increased starch accumulation in grains, yet the uptake and assimilation of essential minerals and nitrogen do not rise proportionally. This imbalance results in nutrient dilution, where calorie content increases while nutrient density declines.

Evidence of Nutrient Decline in Staple Crops

Large-scale experimental studies, particularly Free Air CO₂ Enrichment (FACE) experiments, have consistently demonstrated that elevated CO₂ reduces the concentration of essential nutrients in major crops. Rice and wheat grown under projected future CO₂ levels exhibit marked reductions in iron, zinc, and total protein content. Iron is central to oxygen transport, immune defense, and cognitive development, while zinc is indispensable for immune regulation, antioxidant activity, and gene transcription. Protein decline reflects disruptions in nitrogen metabolism and reduced amino acid synthesis. Because rice and wheat supply a substantial share of daily calories for billions of people, even relatively small nutrient losses translate into major public health risks.

Climate Stressors Beyond CO₂

An exclusive focus on CO₂ underestimates the scale of nutritional disruption. Climate change introduces interacting stressors that further degrade crop quality. Rising temperatures interfere with enzyme activity and protein stability in plants, drought conditions limit mineral solubility and root uptake, and ongoing soil degradation reduces microbial diversity essential for nutrient cycling. Acting together, these pressures compound nutrient loss and erode the resilience of food systems.

Nutrigenomics: How Food Communicates with the Genome

The Foundations of Nutrigenomics

Nutrigenomics examines how nutrients and dietary patterns influence gene expression, epigenetic regulation, and metabolic pathways. Nutrients function not only as sources of energy or structural components but also as biological signals that regulate transcription factors, enzymes, and cellular signaling cascades. Through these mechanisms, diet shapes immune competence, metabolic health, stress responses, and long-term disease susceptibility.

Nutrient–Gene Signaling Under Climate Stress

The nutrients most affected by climate-driven crop changes play critical roles in gene regulation. Iron influences genes involved in mitochondrial function, oxygen sensing, and immune cell proliferation. Zinc is required for the structural integrity of hundreds of zinc-finger transcription factors that control DNA binding and transcriptional regulation. Amino acids and dietary protein activate nutrient-sensing pathways such as mTOR, which govern growth, metabolic balance, and cellular repair. When these nutrients become scarce, gene expression patterns shift toward stress adaptation rather than optimal physiological function.

Epigenetics and Intergenerational Health Effects

One of the most profound implications of altered gene–diet interactions lies in epigenetic regulation, which involves heritable changes in gene expression without alterations to DNA sequence. Nutritional status during critical developmental windows, particularly pregnancy and early childhood, can permanently shape gene expression profiles. Climate-induced deficiencies in iron, zinc, protein, and other micronutrients can modify DNA methylation patterns and histone structures during fetal development. These epigenetic alterations are associated with impaired immune maturation, increased risk of stunting, and heightened susceptibility to metabolic disorders later in life. Such effects may persist across generations, creating a biological legacy of climate change that extends well beyond immediate dietary shortages.

The Gut Microbiome as a Mediator of Gene–Diet Interactions

The gut microbiome forms a crucial interface between diet, genes, and health. Microbial communities influence nutrient absorption, immune signaling, inflammatory regulation, and epigenetic processes. Diets altered by climate change, particularly those lower in protein and micronutrients, can reduce microbial diversity and suppress populations responsible for producing short-chain fatty acids. These metabolites play a key role in regulating gene expression and maintaining immune balance. Microbiome disruption therefore amplifies malnutrition by reducing nutrient bioavailability even when caloric intake appears sufficient, highlighting an indirect yet powerful pathway through which climate change influences human genetics.

Consequences for Immunity and Metabolic Health

Nutrient deficiencies resulting from climate-altered diets have direct consequences for immune function. Insufficient iron and zinc impair lymphocyte proliferation, cytokine production, and antioxidant defenses. Genetic variation in nutrient transport and metabolism further modifies individual vulnerability, leading to uneven health outcomes within the same population. As climate change intensifies nutritional stress, susceptibility to infectious diseases and reduced vaccine responsiveness may increase, particularly in resource-limited settings.

Metabolic health is similarly affected. Protein dilution in staple foods, combined with carbohydrate-dominated diets, disrupts metabolic gene regulation. Interactions with genes controlling insulin sensitivity, lipid metabolism, and appetite regulation elevate the risk of type 2 diabetes, obesity, and cardiovascular disease. In this way, climate change emerges as an indirect yet significant driver of the global burden of non-communicable diseases.

India: A Convergence of Climate Vulnerability, Diet, and Genetic Diversity

India represents a critical case study in climate-driven gene–diet interactions. Heavy reliance on rice and wheat, combined with limited dietary diversity among economically marginalized populations, increases vulnerability to nutrient-poor staples. At the same time, India’s extraordinary genetic diversity shapes variability in nutrient metabolism and disease susceptibility, amplifying differential health outcomes.

Women, children, adolescents, and older adults face disproportionate risks. Women, particularly during pregnancy, have elevated iron and zinc requirements, while children and adolescents are highly sensitive to nutrient-dependent gene regulation during growth and development. Older adults experience declining nutrient absorption and metabolic flexibility. Climate-induced reductions in food quality therefore intensify pre-existing nutritional challenges across life stages.

The health impacts of these changes are not evenly distributed. Communities with limited access to diverse diets experience compounded risks when genetic susceptibility intersects with socioeconomic disadvantage. This convergence raises urgent concerns about environmental and nutritional justice in a warming world.

Policy, Ethics, and Future Directions

Addressing climate-induced disruption of gene–diet interactions requires integrated and forward-looking strategies. Agricultural interventions must prioritise biofortification and crop breeding approaches that maintain micronutrient density under future climate conditions, alongside climate-resilient farming practices that protect soil health and microbial diversity. Public health strategies should incorporate nutrigenomic insights to design targeted nutrition programs for vulnerable populations.

From an ethical standpoint, the decline in food nutritional quality driven by climate change underscores global inequities. Populations least responsible for greenhouse gas emissions often bear the greatest biological consequences, highlighting the need for equity-centered climate and nutrition governance.

            Climate change is reshaping the fundamental relationship between food and human biology. Rising CO₂ levels and associated climate stressors are reducing the nutritional integrity of staple crops, altering gene expression, immune competence, metabolic health, and even epigenetic inheritance. For countries such as India, these changes constitute a silent yet far-reaching public health challenge.

Nutrigenomics offers a powerful framework for understanding and responding to this complexity, revealing that climate change threatens not only food security but biological resilience itself. Protecting human health in the twenty-first century will require reimagining food systems to nourish not just populations, but the genetic and biological potential of present and future generations.