The Healing Power of Minerals, Special Nutrients and Trace Elements by Paul Bergner includes USDA figures that show a decline in mineral and vitamin content of several fruits and vegetables between 1914, 1963, and 1992. Table 1 is a summary of mineral decreases in fruits and vegetables over a 30-year period, adapted from Bergner’s book.
Table 1. Average changes in the mineral content of some fruits and vegetables†, 1963-1992
Mineral Average % Change
† Fruits and vegetables measured: oranges, apples, bananas, carrots, potatoes, corn, tomatoes, celery, romaine lettuce, broccoli, iceberg lettuce, collard greens, and chard. Source