How climate change is making our food less nutritous

By Stephen Beech

Food is less nutritious due to climate change, according to new research.

Scientists say that a combination of higher atmospheric carbon dioxide (CO2) and hotter temperatures contributes to a reduction in nutritional quality in food crops, with "serious" implications for human health and well-being.

Most previous research into the impact of climate change on food production has focused on crop yield.

But the team that conducted the latest study says the size of the harvest means little if the nutritional value is poor.

Jiata Ugwah Ekele, a PhD student at Liverpool John Moores University, said: "Our work looks beyond quantity to the quality of what we eat."

Her research is mainly focused on exploring how the nutritional content of food crops may be affected by the interacting effects of rising CO2 levels and increasing temperatures associated with climate change.

Ekele said: “These environmental changes can affect everything from photosynthesis and growth rates to the synthesis and storage of nutrients in crops.

“It’s crucial to understand these impacts because we are what we eat, and plants form the foundation of our food network as the primary producers of the ecosystem.

“By studying these interactions, we can better predict how climate change will shape the nutritional landscape of our food and work toward mitigating those effects.”

Her research is focused on popular leafy vegetables, including rocket, kale and spinach.

For the new study, the crops were grown in environment-controlled growth chambers at Liverpool John Moores University, and the CO2 and temperature levels were changed to simulate the UK’s predicted future climate scenarios.

Ekele said: “Photosynthetic markers such as chlorophyll fluorescence and quantum yield are assessed as the crops grow, while yield and biomass are recorded at harvest."

After the plants were grown under climate change conditions, their nutritional quality was analyzed using high-performance liquid chromatography (HPLC) and x-ray fluorescence profiling to measure the concentrations of sugar, protein, phenolics, flavonoids, vitamins and antioxidants.

Preliminary results from this project suggest that elevated levels of atmospheric CO₂ can help crops grow faster and bigger, but not healthier.

Ekele said, “After some time, the crops showed a reduction in key minerals like calcium and certain antioxidant compounds."

And the changes were only exacerbated by increases in temperature.

Ekele said: “The interaction between CO₂ and heat stress had complex effects - the crops do not grow as big or fast and the decline in nutritional quality intensifies."

She says a key early finding is that different crops have responded differently to climate change stressors, with some species reacting more intensely than others.

Ekele said: “This diversity in response highlights that we can’t generalise across crops.

"This complexity has been both fascinating and challenging and reminds us why it's important to study multiple stressors together."

She says the nutritional imbalance poses "serious" health implications for humanity.

While higher CO₂ levels can increase the concentration of sugars in crops, it can also dilute essential proteins, minerals and antioxidants.

Ekele said, “This altered balance could contribute to diets that are higher in calories but poorer in nutritional value.

“Increased sugar content in crops, especially fruits and vegetables, could lead to greater risks of obesity and type 2 diabetes, particularly in populations already struggling with non-communicable diseases.”

She says crops with poor nutritional content can also lead to "deficiencies" in vital vitamins and proteins that compromise the human immune system and exacerbate existing health conditions, particularly in low or middle-income countries.

Ekele said: “It’s not just about how much food we grow, but also what’s inside that food and how it supports long-term human well-being."

She says that the implications are global.

Ekele said: “Food systems in the Global North are already being challenged by shifting weather patterns, unpredictable growing seasons, and more frequent heatwaves.

“In tropical and subtropical regions, these areas also contend with overlapping stressors such as drought, pests, and soil degradation, and are home to millions who depend directly on agriculture for food and income.”

She added: “It’s important to connect plant science with broader issues of human well-being.

"As the climate continues to change, we must think holistically about the kind of food system we’re building - one that not only produces enough food, but also promotes health, equity, and resilience.

“Food is more than just calories; it’s a foundation for human development and climate adaptation.”

The findings were presented at the Society for Experimental Biology annual conference in Antwerp, Belgium.