Growing more food but packing less nutrition into it

Studies show declining vitamins and minerals in common crops; regenerative farming is proposed as a fix, but the evidence is mixed and contested.

Several analyses have found that the nutrient content of common crops has fallen over decades. The USDA reported the vitamin C content of lemons dropped by almost a third over 22 years, calcium in carrots fell more than a quarter between the mid-1970s and late 1990s, and the mineral content of wheat declined 20 to 30 percent since the 1960s. Proposed causes include faster-growing crop varieties and higher atmospheric carbon dioxide, which prompts plants to make more sugars and starches with fewer nutrients.

Regenerative agriculture, defined in one study by cover crops, grazing animals, and avoidance of ploughing and pesticides, is offered as a remedy. Research at the University of Lincoln by Francesca Brkic reported striking differences, including iron in kale up to 22 times higher and folate in carrots up to 20,000 times greater on regenerative farms. A 2022 study by David Montgomery and Anne Biklé found some correlation between regenerative practice and nutrient density.

This is a friction on abundance: producing more food means less if each portion carries fewer nutrients. But the evidence cuts both ways. Reviews by UK and French agencies and a large Stanford review found nutrient differences that were small, variable, or insignificant.

The honest picture is unsettled. Regenerative agriculture has no certifiable standard, some supporting studies are small with high variability, and researchers led by Ken Giller doubt it can reliably feed 8.3 billion people while delivering environmental benefits. It also demands more labour and is prone to greenwashing. The nutrient decline is documented; the fix is not proven.

Source: Guardian