Another contributor to the nutrient deficiencies in food is what scientists call the Genetic Dilution Effect, which happens when farmers breed plants to produce high-yield varieties. This declines the nutrient concentration significantly in comparison with the heirloom verities grown years ago.
- Wheat and barley~ Protein concentrations declined by 30-50 percent between the years 1938 and 1990
- Official U.S.D.A. nutrient data shows the calcium content of broccoli averaged 12.9 milligrams per lb of dry weight in 1950, but only 4.4 ml. dry weight in 2003.