According to Michael Pollan’s ‘In Defense of Food,’ “USDA figures show a decline in the nutrient content of the forty-three crops it has tracked since the 1950s…to put this in more concrete terms, you now have to eat three apples to get the same amount of iron as you would have gotten from a single 1940 apple.” (p. 118) The gist of this chapter is that monocultural farming with pesticides and fertilizers has diminished the nutritive properties of soil, and therefore the foods coming out of it are less nutritious. So my question is, are the estimated nutritive values on my spinach and apples based upon these earlier values, or are they periodically re-analyzed to ensure accurate vitamin and mineral content?
Here’s a link the the USDA’s nutrient information
The relevant part:> The Food and Nutrient Database for Dietary Studies (FNDDS) is updated every two years, in conjunction with the two-year cycles of the National Health and Nutrition Examination Survey.