Alex Jack, an author of many books on foods, has compared the nutrients in various fruits as tested by the USDA in 1975 to their 1998 nutrient testing.
In the past 23 years, new agricultural chemicals, weed killers, hybrid and genetically altered seeds, concentrate planting and growing techniques have produced larger fruits in a shorter period of time. The results - less nutrients per gram than by growing the old time tested methods.
Examples of the nutrient changes in an analysis of 12 fruits - apples, apricots, bananas, cherries, grapefruits, lemons, oranges, peaches, pineapples, tangerines, strawberries and watermelons:
Group Net Change
As Alex Jack asks, "Will an apple a day with 40% less vitamin A, 40% less iron and 30% less phosphorus still keep the doctor away?" If it is organically grown, it has a better chance of doing so.
Jack, Alex, "The Disappearing Nutrients in America's Orchards", Candida International, December 12, 2004.