In recent decades, the nutritional quality of fruits and vegetables has undergone a notable transformation. Although advances in agricultural techniques have led to higher yields and larger products, scientific studies show that the concentration of essential nutrients in these crops has decreased significantly. This phenomenon, known as the "dilution effect," refers to the fact that plants accumulate greater amounts of biomass (mainly carbohydrates) without a corresponding increase in minerals, vitamins, and other bioactive compounds.
The dilution effect and crop selection
Comparative studies have shown that crop varieties developed through genetic selection for high yields have lower concentrations of essential nutrients compared to traditional varieties. Genetic engineering and hybridization have led to the development of larger, more resilient fruits and vegetables, but these changes have been accompanied by a reduction in nutrient concentrations such as calcium, iron, phosphorus, vitamin C, and other micronutrients.
Impact of rising carbon dioxide
The increase in atmospheric CO₂ levels, linked to climate change, stimulates photosynthesis and favors the accumulation of carbohydrates in plants. This increase in plant mass, without a corresponding increase in mineral uptake, exacerbates the dilution effect. Experimental studies have shown that crops exposed to high CO₂ levels show a reduction in nutrient concentrations, because the increased carbon input "dilutes" nitrogen compounds and minerals.
Soil quality and intensive agricultural practices
The adoption of intensive farming methods, including the use of synthetic fertilizers and pesticides, has contributed to changes in both plant composition and soil quality. Soil degradation and the decline in microbial biodiversity affect the availability of micronutrients to plants, resulting in reduced uptake and concentration of these nutrients in modern crops.
Personal strategies to improve nutrient intake
Although the problem stems from agricultural practices and environmental conditions, at the individual level, it's possible to take steps to optimize your nutrient intake:
- Diversify your diet: Consuming a wide variety of fruits, vegetables, and other micronutrient-rich foods can partially offset the decreased nutrient density of certain crops.
- Choose local and seasonal products: Foods grown in their natural season and that travel little (reducing the time from harvest to consumption) tend to retain a higher concentration of nutrients.
- Cooking techniques: Using preparation methods that preserve nutrients (e.g., steaming or sautéing instead of boiling) can minimize losses during cooking.
- Responsible supplementation: In cases of documented deficiencies, the use of vitamin and mineral supplements, under professional supervision, can be an effective complementary strategy to meet daily nutritional requirements.
Conclusion
Scientific evidence supports the idea that, despite advances in productivity, the concentration of essential nutrients in fruits and vegetables has declined in recent decades due to the dilution effect, increased CO₂ emissions, and intensive agricultural practices. Understanding these mechanisms is essential for developing strategies to improve the nutritional quality of crops. At the individual level, diversifying diets, choosing seasonal produce, and applying appropriate preparation techniques are measures that can help offset this trend.