Agriculture Reference
In-Depth Information
for reasons of taste or religion, some people use only kosher
or sea salt. This will not pose a problem so long as they eat
vegetables from soils sufficient in iodine, but in some regions
this is not the case.
There are many challenges when comparing food nutri-
ents today with food nutrients in the past, but most evi-
dence suggests that fruits and vegetables today are less
nutrient-dense. The decrease is not alarming, though, as the
USDA has shown that the nutrient composition of food hasn't
changed much in the last century. Moreover, in cases where
the nutrient composition fell, soil quality was not necessar-
ily the problem. Different nutrient measurement methods,
alternative ways of handling food, and new crop varieties are
also a factor. Consumer preferences matter also. Although
wild crab apples contain more phytonutrients than modern
farmed apples, crab apples are barely edible. What good is a
nutrient-dense food if no one eats it? Also, it should be noted
that there are some cases where farmers and breeders are
actively trying to increase the nutrient content of food.
Are chemical fertilizers to blame for the decline in nutrient
density? Research suggests the blame mostly belongs to new
crop varieties. With the rise of chemical fertilizer also came
higher-yielding crop varieties. These more efficient varieties of
grains, fruits, and vegetables are subject to the genetic dilution
effect, a concept describing the trade-off between yield and
nutrition. These improved varieties of plants achieve a higher
yield in two ways: by taking more nutrients from the earth
and by packing less nutrients per unit of food. Thus, the new
crop varieties are probably the major source of nutrient loss in
foods today. This was illustrated nicely on the Broadbalk fields
in England, where experimental plots have been maintained
since 1843. Between 1843 and the 1960s the concentration of
micronutrients in the wheat harvested remained steady, but
then began falling, giving the impression that the soil was
running out of zinc, iron, copper, and magnesium. However,
the amount of these micronutrients in the soil had remained
