AsianScientist (Jun. 04, 2025) – What if climate change wasn’t just altering the air we breathe or the crops we grow—but also the microbes living inside our bodies? A new review in The Lancet Planetary Health highlights how rising temperatures, extreme weather, and shrinking food quality are quietly reshaping the human gut microbiome
“The gut microbiome could serve as a sensitive biosensor for climate-related health vulnerability,” said Elena Litchman, microbial ecologist at Michigan State University and lead author of the review. “Shifts in gut microbial composition might offer early warning signs of climate stress in human populations, helping guide targeted interventions. But global microbiome research remains heavily skewed toward high-income countries. Without broader data—especially from Asia, Africa, and Latin America—we risk missing how climate change is truly reshaping human biology.”As climate stressors disrupt global food systems and reduce access to nutritious diets, the diversity and resilience of gut microbes are being undermined—particularly in low- and middle-income countries such as India, Bangladesh, Pakistan, Nepal, Indonesia, and the Philippines, where communities already facing high burdens of malnutrition and waterborne diseases are now contending with the added pressures of extreme heat, erratic rainfall, and declining food quality. The study warns that these shifts may worsen existing health inequalities, with microbiome imbalances linked to everything from stunted growth to metabolic diseases.
The clearest link between climate change and gut health comes through food. Elevated atmospheric carbon dioxide has been shown to reduce the nutritional value of staple crops like rice, maize, and wheat. Key micronutrients such as zinc, iron, and potassium—as well as protein—drop in concentration when plants grow under high-CO₂ conditions. While these effects may seem subtle, they accumulate over time and pose a major threat to populations already vulnerable to undernutrition.
Gut microbes are highly responsive to what we eat. Diets lacking in fiber, micronutrients, and dietary diversity are known to reduce microbial richness and resilience, making individuals more susceptible to infections, inflammation, and metabolic disorders. For children, early-life malnutrition can permanently disrupt microbiome development, with lifelong health consequences. The review points out that these effects will intensify as food insecurity grows in climate-stressed regions. These trends are especially alarming in South Asia, where climate change is projected to reduce cereal yields by up to 40% by 2050, exacerbating food insecurity and limiting access to the diverse, nutrient-rich diets essential for healthy gut microbiomes. TK
Moreover, traditional food systems—particularly in Indigenous and rural communities—are also under threat. Their diets tend to include fermented foods that naturally replenish beneficial gut bacteria. But as climate change disrupts their agricultural cycles, food storage conditions, and foraging patterns, the communities may have to shift to industrialized or processed foods, which are typically poor in fiber and nutrients but high in sugars and preservatives—ingredients that can further damage microbial balance.
The problem isn’t limited to what we eat. Climate change is also transforming the broader microbial environments we interact with daily, according to the review. Soil, plants, animals, and even air carry microbes that interact with the human microbiome, especially during early childhood. As ecosystems are destroyed by deforestation, urbanization, and biodiversity loss, the microbial diversity in our surroundings also shrinks—limiting the range of microbes we are exposed to.
Pollution adds another layer. Increased pesticide use, exposure to microplastics, and contamination by heavy metals in food and water are all rising due to climate stress on agriculture and infrastructure. These substances have been shown to negatively affect gut bacteria, killing off beneficial species and promoting the growth of harmful ones. In countries with limited access to clean water or healthcare, these risks multiply.
With Asia home to many of the world’s most climate-vulnerable populations, the gut microbiome offers a crucial—but overlooked—lens into how climate change is reshaping health from the inside out. Without region-specific data, we may miss early warning signs hiding in our own bodies.
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Source: Michigan State University ; Image: The Lancet Planetary Health/Asian Scientist Magazine
The study can be found at: Climate change effects on the human gut microbiome: complex mechanisms and global inequities