Environmental Engineering Reference
In-Depth Information
robust roots that more aggressively absorb nutrients from the soil. And
high-yielding crops generate fewer phytochemicals—health-promoting
compounds like antioxidants and vitamins. Nutrient defi ciencies in
Americans are common, even among the well fed. The yield/nutrient
dilemma is simply another example of human interference in natural
processes causing harm. In fact, natural processes tend to lead to the
most healthful outcomes.
Many Americans who worry about the lack of nutrients in the pro-
cessed foods they eat take vitamin supplements, believing that they will
improve their health. They consume cheap processed foods that make
them sick and then spend billions on expensive products to keep them
healthy. Today about half of all adults in the United States use some
form of dietary supplement.
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However, it is not clear that ingesting
nutrients in pill form has the same benefi ts as eating nutrient-rich fruits
and vegetables. In the past few years, several high-quality studies have
failed to show that extra vitamins in pill form help prevent chronic
disease or prolong life. As Eric Klein, chairman of the Cleveland Clinic's
Urologic and Kidney Institute, noted, “The public's belief in the benefi ts
of vitamins and nutrients is not supported by the available scientifi c
data.”
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Scientists suspect that the benefi ts of a healthful diet come from eating
the whole fruit or vegetable, not just the individual vitamins it contains.
This seems reasonable from an evolutionary viewpoint. There may not
be a single component of broccoli or green leafy vegetables that is respon-
sible for most of its health benefi ts. The reductionist approach of con-
sidering the effect of one or two chemicals in isolation may be an
ineffective way to recognize the collaborative benefi ts of eating the entire
plant that contains the vitamins.
Will Climate Change Affect Crop Production?
Several factors connect agricultural productivity and climate change:
Average temperature increase
Change in rainfall amount and distribution
Rising atmospheric concentrations of carbon dioxide
Pollution levels such as tropospheric ozone (smog)
Change in climatic variability and extreme events
Few studies of climate change on agriculture have considered all of these
factors:
