LESSONS FROM CHINA 89
cia ted with cancer in families? Absolutely. Every single animal protein-
related blood biomarker is significantly associated with the amount of
cancer in a family.lI-m
In this case, multiple observations, tightly networked into a web,
show that animal-based foods are strongly linked to breast cancer. What
makes this conclusion especially compelling are two kinds of evidence.
First, the individual parts of this web were consistently correlated and,
in most cases, were statistically significant. Second, this effect occurred
at unusually low intakes of animal-based foods.
Our investigation of breast cancer (detailed further in chapter seven)
is a perfect example of what makes the China Study so convincing.
Rather than a single, simple association of fat and breast cancer,! we were
able to construct a much more expansive web of information about how
diet affects breast cancer risk. We were able to examine in multiple ways
the role of diet and cholesterol, age of menarche and female hormone
levels, all of which are known risk factors for breast cancer. When each
new finding pointed in the same direction, we were able to see a picture
that was convincing, consistent and biologically plausible.THE IMPORTANCE OF FIBER
The late Professor Denis Burkitt, of Trinity College, Dublin, was un-
usually articulate. His common sense, scientific credibility and sense
of humor made quite an impression on me when 1 first met him at a
Cornell seminar. The subject of his work was dietary fiber. He had trav-
eled 10,000 miles in ajeep over rugged countryside to study the dietary
habits of Africans.
He asserted that even though fiber was not digested, it was vital for
good health. Fiber was able to pull water from the body into the intestines
to keep things moving along. These undigested fibers, like stick-urn pa-
per, also gather up nasty chemicals that find their way into our intestines
and that might be carcinogenic. If we don't consume enough fiber, we are
susceptible to constipation-based diseases. According to Burkitt, these in-
clude large bowel cancer, diverticulosis, hemorrhoids and varicose veins.
In 1993, Dr. Burkitt was awarded the prestigious Bower Award, the
richest award in the world next to the Nobel Prize. He invited me to
speak at his award ceremony at the Franklin Institute in Philadelphia,
only two months before his unfortunate passing. He offered his opinion
that our China Study was the most significant work on diet and health
in the world at that time.