On Food and Cooking

cancer; some prevent the body from turning
mildly toxic chemicals into more powerful
toxins that damage DNA and cause cancer;
some inhibit the growth of cells that are
already cancerous. Others slow the loss of
calcium from our bones, encourage the growth
of beneficial bacteria in our system, and
discourage the growth of disease bacteria.
The box on p. 256 lists some of these
effects, and the chemicals and plants that
cause them. Our knowledge of this aspect of
nutrition is still in its infancy, but we know
enough right now for at least one conclusion
to be evident: no single fruit or vegetable
offers the many kinds of protections that a
varied diet can provide.
So today’s provisional nutritional wisdom
goes like this: fruits and vegetables, herbs and
spices supply us with many different
beneficial substances. Within an otherwise
adequate diet, we should eat as much of them
as we can, and as great a variety as we can.