Vegetables grown at higher carbon dioxide (CO2) concentrations may grow better but may not have the same nutritional benefits.
Increasing atmospheric CO2 concentrations have prompted research into the effect of this phenomenon on plant growth. In general, elevated CO2 is good for plant growth, increasing yield and environmental stress tolerance. However, a review of the research in this field has found that elevated CO2 also reduces the magnesium, iron and zinc content of vegetables. This reduction was as much as 31% for iron in leafy greens.
In specific vegetables, the review found that sugar content of lettuce, tomatoes and potatoes increased at higher atmospheric CO2 concentrations, while protein content decreased. Other factors, such as antioxidant content, were strongly affected, but this effect was different between different vegetable cultivars.
Higher yields with lower protein content have also been found for staple crops and grains grown at elevated CO2 concentrations. These changes occurred alongside reduced iron and zinc content.
In a future with increased atmospheric CO2 concentrations, our crops and vegetables may grow larger and sweeter, but the amounts of other essential nutrients that we get from them may decrease. This could lead to higher caloric intakes required to obtain the same amount of nutrients from these foods. While the concentrations reviewed in this publication were high compared to those expected in the near future, we should be prepared for some degree of impact on our crops. Targeting crop varieties which make the best of the changing conditions is being explored.
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