Authors: T. Colin Campbell,Thomas M. Campbell
200 THE CHINA STUDY
to fish might have a protective effect. What is almost never mentioned,
however, is that dairy consumption (and saturated fat) was much lower
in the fish-eating areas. Is it possible that cow's milk and lack of sun-
s h i n e are having a similar effect on MS and other autoimmune diseases
because they operate through a similar mechanism? This could be very
interesting, if true.
As it turns out, the idea is not so crazy. This mechanism involves,
once again, vitamin D. There are experimental animal models of lupus,
MS, rheumatoid arthritis and inflammatory bowel disease (e.g., Crohn's
disease, ulcerative colitis), each of which is an autoimmune disease. 6 • 7. 68
Vitamin D, operating through a similar mechanism in each case, prevents
the experimental development of each of these diseases. This becomes
an even more intriguing story when we think about the effect of food on
vitamin D.
The first step in the vitamin D process occurs when you go outside
on a sunny day. When the sunshine hits your exposed skin, the skin
produces vitamin D. The vitamin D then must be activated in the kid-
ney in order to produce a form that helps repress the development of
autoimmune diseases. As we've seen before, this critically important
activation step can be inhibited by foods that are high in calcium and
by acid-producing animal proteins like cow's milk (some grains also
produce excess acid). Under experimental conditions, the activated
vitamin D operates in two ways: it inhibits the development of certain
T-cells and their production of active agents (called cytokines) that
initiate the autoimmune response, and/or it encourages the production
of other T-cells that oppose this effect. 69. 70 (An abbreviated schematic
of this vitamin D network is shown in Appendix C.) This mechanism
of action appears to be a strong commonality between all autoimmune
diseases so far studied.
Knowing the strength of the evidence against animal foods, cow's milk
in particular, for both MS and Type 1 diabetes, and knowing how much
in common all of the autoimmune diseases have, it is reasonable to be-
gin thinking about food and its relationship to a much broader group of
autoimmune diseases. ObViously caution is called for; more research is
needed to make conclusive statements about cross-autoimmune disease
similarities. But the evidence we have now is already striking.
Today almost no indication of the dietary connection to these dis-
eases has reached public awareness. The Web site of the Multiple Scle-
rosis International Federation, for example, reads, "There is no credible
AUTOIMMUNE DISEASES 201
evidence that MS is due to poor diet or dietary deficiencies." They warn
that dietary regimens can be "expensive" and "can alter the normal
nutritional balance."7l If changing your diet is expensive, I don't know
what they would say about being bedridden and incapacitated. As far as
altering the "normal nutritional balance" is concerned, what is normal?
Does this mean the diet that we now eat is "normal"-the diet that is
largely responsible for diseases that cripple, kill and make profoundly
miserable millions of Americans every year? Are massive rates of heart
disease, cancer, autoimmune diseases, obesity and diabetes "normal"? If
this is normal, I propose we start seriously considering the abnormal.
There are 400,000 Americans who are victims of multiple sclerosis,
and millions more with other autoimmune diseases. While statistics,
research results and clinical descriptions form the basis for much of my
discussion of diet and disease, the importance of the information comes
down to the intimate experience of individual people. Anyone of these
serious diseases I've talked about in this chapter can forever alter the
life of any person-a family member, a friend, a neighbor, a coworker
or you yourself.
It is time to sacrifice our sacred cows. Reason must prevail. Profes-
sional societies, doctors and government agencies need to stand up and
do their duty, so that children being born today do not face tragedies
that otherwise could be prevented.
__............... _........._........_.__.............____ ._ ._ ._._._.....___.........._..._ ___ ..........
....... .__ ..__ ..__ _ ._ 0 .____ . __ ... . . __ 1 . ._
Wide-Ranging Effects:
Bone, Kidney, Eye
and Brain Diseases
OF THE MOST CONVINCING ARGUMENTS for a plant-based diet is the fact
ONE
that it prevents a broad range of diseases. If I have a conversation with
someone about a single study showing the protective effect of fruits
and vegetables on heart disease, they may agree that it's all very nice for
fruits and vegetables, but they will probably still go home to meatloaf
and gravy. It doesn't matter how big the study, how persuasive the re-
s u l t s or how respectable the scientists who conducted the investigation.
The fact is that most people have a healthy skepticism about one study
standing alone-as well they should.
But if I tell them about dozens and dozens of studies showing that the
countries with low rates of heart disease consume low amounts of animal-
based foods, and dozens and dozens of studies showing that individuals
who eat more whole, plant-based foods get less heart disease, and I go on
to document still more studies showing that a diet low in animal-based
foods and high in unprocessed plant-based foods can slow or reverse
heart disease, then people are more inclined to pay some attention.
If I keep talking and go through this process not only for heart dis-
ease, but obesity, Type 2 diabetes, breast cancer, colon cancer, prostate
203
204 THE CHINA STUDY
cancer, multiple sclerosis and other autoimmune diseases, it's quite pos-
sible that people may never eat meatloaf and gravy again.
What has become so convincing about the effect of diet on health is
the breadth of the evidence. While a single study might be found to sup-
p o r t almost any idea under the sun, what are the chances that hundreds,
even thousands, of different studies show a protective benefit of plant-
based foods and/or harmful effects of animal-based foods for so many
different diseases? We can't say it's due to coincidence, bad data, biased
research, misinterpreted statistics or "playing with numbers." This has
got to be the real deal.
I have so far presented only a small sample of the breadth of evidence
that supports plant-based diets. To show you just how broad this evi-
dence is, I will cover five more seemingly unrelated diseases common
in America: osteoporosis, kidney stones, blindness, cognitive dysfunc-
t i o n and Alzheimer's disease. These disorders are not often fatal and are
often regarded as the inevitable consequences of aging. Therefore, we
don't think it's unnatural when grandpa gets blurry spots in his vision,
can't remember the names of his friends or needs a hip replacement op-
eration. But, as we shall see, even these diseases have a dietary link.
OSTEOPOROSIS
Did you ever have an elementary school teacher tell you that if you
didn't have bones, you would just be a shapeless blob on the floor? Or
maybe you learned about the human skeleton from that popular song,
" ... the ankle bone is connected to the shin bone, the shin bone is con-
n e c t e d to the knee bone," etc. At that same time in your life, you prob-
ably were told to drink milk to build strong bones and teeth. Because
none of us want to be shapeless blobs, and because our celebrities have
been paid to advertise milk's presumed benefits, we drank it. Milk is to
bone health as bees are to honey.
Americans consume more cow's milk and its products per person
than most populations in the world. So Americans should have wonder-
fully strong bones, right? Unfortunately not. A recent study showed that
American women aged fifty and older have one of the highest rates of hip
fractures in the world. l The only countries with higher rates are in Europe
and in the south Pacific (Australia and New Zealand)l where they con-
s u m e even more milk than the United States. What's going on?
An excess rate of hip fractures is often used as a reliable indicator of
osteoporosis, a bone disease that especially affects women after meno-
WIDE-RANGING EFFECTS: BONE, KIDNEY, EYE, BRAIN DISEASES 205
pause. It is often claimed to be due to an inadequate intake of calcium.
Therefore, health policy people often recommend higher calcium con-
s u m p t i o n . Dairy products are particularly rich in calcium, so the dairy
industry eagerly supports efforts to boost calcium consumption. These
efforts have something to do with why you were told to drink your milk
for strong bones-the politics of which are discussed in Part IV.
Something is amiss, though, because those countries that use the
most cow's milk and its products also have the highest fracture rates and
the worst bone health. One possible explanation is found in a report
showing an impressively strong association between animal protein
intake and bone fracture rate for women in different countries.2 Au-
t h o r e d in 1992 by researchers at Yale University School of Medicine, the
report summarized data on protein intake and fracture rates taken from
thirty-four separate surveys in sixteen countries that were published
in twenty-nine peer-reviewed research publications. All the subjects in
these surveys were women fifty years and older. It found that a very
impressive 70% of the fracture rate was attributable to the consumption
of animal protein.
These researchers explained that animal protein, unlike plant pro-
tein , increases the acid load in the body.3 An increased acid load means
that our blood and tissues become more acidic. The body does not like
this acidic environment and begins to fight it. In order to neutralize the
acid, the body uses calcium, which acts as a very effective base. This
calcium, however, must come from somewhere. It ends up being pulled
from the bones, and the calcium loss weakens them, putting them at
greater risk for fracture .
We have had evidence for well over a hundred years that animal pro-
tein decreases bone health. The explanation of animal protein causing
excess metabolic acid, for example, was first suggested in the 1880s4
and was documented as long ago as 1920.5 We also have known that
animal protein is more effective than plant protein at increasing the
metabolic acid load in the body.6. 7,8
When animal protein increases metabolic acid and draws calcium
from the bones, the amount of calcium in the urine is increased. This
effect has been established for over eighty years 5 and has been studied
in some detail since the 1970s. Summaries of these studies were pub-
lished in 1974,9 198po and 1990Y Each of these summaries clearly
shows that the amount of animal protein consumed by many of us on
a daily basis is capable of causing substantial increases in urinary cal-
~
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f
206 THE CHINA STUDY
CHART 10.1: ASSOCIATION OF URINARY CALCIUM EXCRETION
WITH DIETARY PROTEIN INTAKE
(2).
100
.(4)
E • (1)
::J
'u .(33)
m .(5)
u • (2)
~
rc
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§
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.~
OJ
Vl
Y=0.50X
rc
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u
r =0.85
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";R.
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100 200
% Increase in Protein Intake
cium. Chart 10.1 is taken from the 1981 publication. 10 Doubling protein
intake (mostly animal-based) from 35-78 glday causes an alarming 50%
increase in urinary calcium. This effect occurs well within the range
of protein intake that most of us consume; average American intake is
around 70-100 glday. Incidentally, as mentioned in chapter four, a six-
m o n t h study funded by the Atkins Center found that those people who
adopted the Atkins Diet excreted 50% more calcium in their urine after
six months on the diet. 12
The initial observations on the association between animal protein
consumption and bone fracture rates are very impressive, and now we
have a plausible explanation as to how the association might work, a
mechanism of action.
Disease processes are rarely as simple as "one mechanism does it all,"
but the work being done in this field makes a strong argument. A more
recent study, published in 2000, comes from the Department of Medi-
cine at the University of California at San Francisco. Using eighty-seven
surveys in thirty-three countries, it compared the ratio of vegetable to
animal protein consumption to the rate of bone fractures (Chart 10.2).1
A high ratio of vegetable to animal protein consumption was found to
be impressively associated with a virtual disappearance of bone frac-
tures.
These studies are compelling for several reasons. They were published
in leading research journals, the authors were careful in their analyses and
WID E- RAN GIN G EF FE CT S: BON E,K ION EY EYE BRA I N 0 I SE ASES 207
I I
CHART 10.2: ASSOCIATION OF ANIMAL VERSUS PLANT PROTEIN
INTAKE AND BONE FRACTURE RATES FOR DIFFERENT COUNTRIES
200
175
150
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Vegetable-to-Animal Protein Intake Ratio (gig)
interpretation of data, they included a large number of individual research
reports, and the statistical significance of the association of animal protein
with bone fracture rates is truly exceptional. They cannot be dismissed as
just another couple of studies; the most recent study represents a sum-
mary of eighty-seven separate surveys!
The Study of Osteoporotic Fractures Research Group at the Univer-
sity of California at San Francisco published yet another study13 of over
1,000 women aged Sixty-five and up. Like the multi-country study, re-
searchers characterized women's diets by the proportions of animal and
plant protein. After seven years of observations, the women with the
highest ratio of animal protein to plant protein had 3.7 times more bone
fractures than the women with the lowest ratio. Also during this time
the women with the high ratio lost bone almost four times as fast as the
women with the lowest ratio.
Experimentally, this study is high quality because it compared pro-
tein consumption, bone loss and broken bones for the same subjects.
This 3.7-fold effect is substantial, and is very important because the
I