Agriculture Reference
In-Depth Information
steady or increased, leading researchers to conclude it was the
choice of wheat varieties planted that reduced the nutrient
content of the wheat, not soil deficiencies.
Of course, the nutrient content of food is less important
than access to total nutrients. What good is a nutrient-dense
food supply if there is little of it to go around? Even if the nutri-
ent content of food has fallen, agriculture has become increas-
ingly productive, suggesting the total per capita nutrients in
the food supply might be rising. Indeed, that seems to be the
case. Figure 3.1 looks at how total access to nutrients in the US
food supply has changed in the last century, and what it shows
is true using a variety of measures, like food energy, protein,
vitamins, and minerals. The results are clear and striking: our
access to nutrients has risen over time in every measure except
potassium, which declined only slightly. Increases in magne-
sium, vitamin B12, and selenium were unremarkable, but all
things considered, if soils are becoming less fertile, it is not
manifested in the total amount of nutrients available to US
citizens. The same is likely to be true in western Europe.
Greater nutrient availability doesn't necessarily mean
greater nutrient consumption, if patterns of food waste are
changing at the same time more nutrients are produced.
Studies of nutrient consumption in the United Kingdom find
that per-person intake of some micronutrients like magne-
sium, iron, zinc, and copper has fallen over time, and in some
cases is insufficient for a person's daily nutrient needs. While
there are nutrient deficiencies in the United States also, they
have not changed much since 1999. The purpose of including
figure 3.1 is not to imply that there are no micronutrient defi-
ciencies in the United States, but that the persistent use of chem-
ical fertilizers does not seem to pose a micronutrient problem.
Another way to inquire whether chemical fertilizers affect
the nutrient content of food is to compare nonorganic food to
organic food. Most of the time nonorganic food is raised using
mostly chemical fertilizers, whereas organic food must use
other sources. Many scientific comparisons have been made,
