Here’s a dirty little secret about the food you’re eating: Soil depletion appears to be sapping nutrients from the fruits and vegetables that wind up on your dinner table.
“Ever since humans developed agriculture, we’ve been transforming the planet and throwing the soil’s nutrient cycle out of balance,” says Ronald Amundson, a University of California-Berkeley professor who co-authored a 2015 study on soil depletion. “Because the changes happen slowly, often taking two to three generations to be noticed, people are not cognizant of the geological transformation taking place.”
Nutrients in food being impaired by soil depletion include protein, calcium, phosphorus, iron, riboflavin and ascorbic acid, according to a study published in 2004 by University of Texas at Austin researchers. The study relied on data about 43 garden crops spanning five decades (1950 to 1999). Other nutrients that could be compromised by soil depletion, but weren’t part of the study, include magnesium, zinc, vitamin B-6 and vitamin E.
“Efforts to breed new varieties of crops that provide greater yield, pest resistance and climate adaptability have allowed crops to grow bigger and more rapidly, but their ability to manufacture or uptake nutrients has not kept pace with their rapid growth,” the University of Texas study says.
According to research cited by Courtney White, author of “Grass, Soil, Hope,” a study in Australia found that apples had lost 80 percent of their vitamin C between 1948 and 1991 due to soil depletion, and the vitamin A content of carrots had plummeted by 99 percent. Meanwhile, in a United Kingdom study cited by White, nearly all vegetables had seen copper reduced by 76 percent, calcium by 46 percent, iron by 27 percent, magnesium by 24 percent and potassium by 16 percent. The U.K. study covered the 50-year period from 1940 to 1990.
A 2005 study goes as far as to declare that nutrient depletion harms soil quality and reduces crop yields and, therefore, threatens global food security and agricultural sustainability.
Keep in mind that the notion of depletion of soil has its detractors. An online search for the term “soil depletion” turns up articles and blog posts characterizing it as a “scandal,” a “fairy tale” and a “myth.”
“Vitamins are not found loose in the soil just waiting for plants to soak them up into their roots. Plants make vitamins from several building blocks in the soil,” according to one critic. “Minerals are taken up from the soil, but if there is a deficiency in a mineral needed for plant growth, it simply will not produce viable amounts of fruits or vegetables.”
“Soil quality is a major factor in the declining health of Americans,” Schreiber says. “Over the years, we have over-farmed the land and have not rotated crops in the name of profit. This results in nutrient depletion.”
Soil depletion affects your health whether you’re eating nutrient-depleted plants or eating meat from animals that have consumed nutrient-depleted plants, Schreiber says.
“When a certain nutrient is deficient or completely lacking, the body and mind will not function normally,” says dentist and mind-and-body expert Dr. T.K. Stone, author of “The Fertile Ground.” “When the complete nutrition for a plant or animal is lacking nutrients, there are consequences, like weak immunity.”
Despite the mounting evidence of soil depletion, the University of Texas study emphasizes the value of continuing to eat fruits and vegetables.
“Vegetables are extraordinarily rich in nutrients and beneficial phytochemicals,” the study says. “They are still there, and vegetables and fruits are our best sources for these.”