Authors: T. Colin Campbell,Thomas M. Campbell
THE CHINA STUDY
208
women with the lowest bone fracture rates still consumed, on average,
about half of their total protein from animal sources. I can't help but
wonder how much greater the difference might have been had they con-
s u m e d not 50% but 0-10% of their total protein from animal sources. In
our rural China study, where the animal to plant ratio was about 10%,
the fracture rate is only one-fifth that of the U.S. Nigeria shows an ani-
m a l - t o - p l a n t protein ratio only about 10% that of Germany, and the hip
fracture incidence is lower by over 99%.1
These observations raise a serious question about the widely adver-
tised claim that protein-rich dairy foods protect our bones. And yet we
still are warned almost daily about our need for dairy foods to provide
calcium for strong bones. An avalanche of commentary warns that most
of us are not meeting our calcium requirements, especially pregnant and
lactating women. This calcium bonanza, however, is not justified. In
one study of ten countries,14 a higher consumption of calcium was as-
sociated with a higher-not lower-risk of bone fracture (Chart 10.3) .
Much of the calcium intake shown in this chart, especially in high con-
s u m p t i o n countries, is due to dairy foods, rather than calcium supple-
m e n t s or non-dairy food sources of calcium.
Mark Hegsted, who produced the results in Chart 10.3, was a long-
time Harvard professor. He worked on the calcium issue beginning in the
early 1950s, was a principal architect of the nation's first dietary guide-
lines in 1980 and in 1986 published this graph. Professor Hegsted be-
lieves that excessively high intakes of calcium consumed over a long time
impair the body's ability to control how much calcium it uses and when.
Under healthy conditions, the body uses an activated form of vitamin
D, calcitriol, to adjust how much calcium it absorbs from food and how
much it excretes and distributes in the bone. Calcitriol is considered a
hormone; when more calcium is needed, it enhances calcium absorption
and restricts calcium excretion. If too much calcium is consumed over a
long period of time, the body may lose its ability to regulate calcitriol, per-
manently or temporarily disrupting the regulation of calcium absorption
and excretion. Ruining the regulatory mechanism in this way is a recipe
for osteoporosis in menopausal and post-menopausal women. Women at
this stage of life must be able to enhance their utilization of calcium in a
timely manner, especially if they continue to consume a diet high in ani-
mal protein. The fact that the body loses its ability to control finely tuned
mechanisms when they are subjected to continuous abuse is a well-estab-
lished phenomenon in biology.
WID E- RAN GIN G EF FECT S: BON E,K I DNEY EY E BRA I N DIS EASE S 209
I I
CHART 10.3: ASSOCIATION OF RATES OF HIP FRACTURES
WITH CALCIUM INTAKE FOR DIFFERENT COUNTRIES
120
• UNITED STATES
100
• NEW ZEALAND
0
0
0 • SWEDEN
0"
0
80
(jj
"-
• JERUSALEM
Vl
~
~
• UNITED KINGDOM
t
60
~
L.L.
0-
£ • HOLLAND • FINLAND
'0
OJ
40
u
• YUGOSLAVIA
c
OJ
-c
·0
• HONG KONG
.E
20
• SINGAPORE
o
o 500 1,000 1,500
Calcium Consumption (mg/day)
Given these findings, it seems perfectly plausible that animal protein
and even calcium-when consumed at excessive levels-are capable of
increasing the risk of osteoporosis. Dairy, unfortunately, is the only food
that is rich in both of these nutrients. Hegsted, backed by his excep-
tional experience in calcium research, said in his 1986 paper, " . . . hip
fractures are more frequent in populations where dairy products are
commonly consumed and calcium intakes are relatively high."
Years later, the dairy industry still suggests that we should be consum-
i n g more of its products to build strong bones and teeth. The confusion,
conflict and controversy rampant in this area of research allow anybody
to say just about anything. And of course, huge amounts of money are at
stake as well. One of the most cited osteoporosis experts-one funded
by the dairy industry-angrily wrote in a prominent editoriaP5 that the
findings favoring a diet with a higher ratio of plant-to-animal protein
cited above could have been "influenced to some extent by currents in
210 THE CHINA STUDY
the larger society." The "currents" he was referring to were the animal
rights activists opposed to the use of dairy foods .
Much of the debate regarding osteoporosis, whether it is conducted
with integrity or otherwise, resides in the research concerning the de-
tails. As you shall see, the devil lurks in the details, the primary detail
being that of bone mineral density (BMD) .
Many scientists have investigated how various diet and lifestyle fac-
tors affect BMD. BMD is a measure of bone density that is often used to
diagnose bone health. If your bone density falls below a certain level,
you may be at risk for osteoporosis. In practical terms, this means that
if you have a low BMD , you are at a higher risk for a fracture. I 6-18 But
there are some devilishly contradictory and confUSing details in this
great circus of osteoporosis research. To name a few:
• A high BMD increases the risk of osteoarthritis. 19
• A high BMD has been linked to a higher risk of breast cancer.2 , 21
0
• Although high BMD is linked both to increased breast cancer risk
and decreased osteoporotic risk, breast cancer and osteoporosis
nonetheless cluster together in the same areas of the world and
even in the same individuals.22
• Rate of bone loss matters just as much as overall BMD.23
• There are places where overall bone mass, bone mineral density
or bone mineral content measurements are lower than they are in
"Western" countries, but the fracture rate also is lower, defying ac-
cepted logic of how we define "big, strong bones."24--26
• Being fat is linked to greater BMD,H, 27 even though areas of the
world that have higher rates of obesity also have higher rates of
osteoporosis.
Something is wrong with the idea that BMD reliably represents os-
teoporosis and, by inference, indicates the kind of diet that would lower
fracture rates. In contrast, an alternative, but much better, predictor
of osteoporosis is the dietary ratio of animal-to-plant protein. I, 13 The
higher the ratio, the higher the risk of disease. And guess what? BMD is
not significantly associated with this ratio.13
Clearly the conventional recommendations regarding animal foods,
dairy and bone mineral density, which are influenced and advertised by
the dairy industry, are besieged by serious doubts in the literature. Here
is what I would recommend you do, based on the research, to minimize
your risk of osteoporosis:
WIDE-RANGING EFFECTS: BONE, KIDNEY, EYE, BRAIN DISEASES 211
• Stay physically active. Take the stairs instead of the elevator, go for
walks, jogs, bicycle rides. Swim, do yoga or aerobics every couple
of days and don't be afraid to buy barbells to use once in a while.
Playa sport or join a social group that incorporates exercise. The
possibilities are endless, and they can be fun. You'll feel better, and
your bones will be much healthier for the effort.
• Eat a variety of whole plant foods, and avoid animal foods, includ-
ing dairy. Plenty of calcium is available in a wide range of plant
foods, including beans and leafy vegetables. As long as you stay
away from refined carbohydrates, like sugary cereals, candies,
plain pastas and white breads, you should have no problem with
calcium deficiency.
• Keep your salt intake to a minimum. Avoid highly processed and
packaged foods, which contain excess salt. There is some evidence
that excessive salt intake can be a problem.
KIDNEYS
At the Web site for the UCLA Kidney Stone Treatment Center,28 you will
discover that kidney stones may cause the following symptoms:
• Nausea, vomiting
• Restlessness (trying to find comfortable position to ease the pain)
• Dull pain (ill-defined, lumbar, abdominal, intermittent pain)
• Urgency (urge to empty the bladder)
• Frequency (frequent urination)
• Bloody urine with pain (gross hematuria)
• Fever (when complicated by infection)
• Acute renal colic (severe colicky flank pain radiating to groin, scro-
t u m , labia)
Acute renal colic deserves some explanation. This agonizing symp-
t o m is the result of a crystallized stone trying to pass through the thin
tube in your body (ureter) that transports urine from the kidney to the
bladder. In describing the pain involved, the Web site states, "This is
probably one of the worst pains humans experience. Those who have
had it will never forget it .... The severe pain of renal colic needs to be
controlled by potent pain killers. Don't expect an aspirin to do the trick.
Get yourself to a doctor or an emergency room. "28
I don't know about you, but just thinking about these things gives me
THE CHINA STUDY
212
a shiver. Unfortunately, up to 15% of Americans, more men than wom-
e n , will be diagnosed with having a kidney stone in their lifetime.29
There are several kinds of kidney stones. Although one is a geneti-
cally rare type 30 and another is related to urinary infection, the major-
ity involve stones made of calcium and oxalate. These calcium oxalate
stones are relatively common in developed countries and relatively rare
in developing countries. 3l Again, this illness falls into the same global
patterns as all the other Western diseases.
I first was made aware of the dietary connection with this disease at
the Faculty of Medicine of the University of Toronto. I was invited to
give a seminar on our China Study findings and while there I met Pro-
fessor W G. Robertson from the Medical Research Council in Leeds,
England. This chance encounter was extremely rewarding. Dr. Robert-
son, as I have come to learn, is one of the world's foremost experts on
diet and kidney stones. Dr. Robertson's research group has investigated
the relationship between food and kidney stones with great depth and
breadth, both in theory and in practice. Their work began more than
thirty years ago and continues to the present day. A search of the scien-
tific publications authored or co-authored by Robertson shows at least
100 papers published since the mid-1960s.
One of Robertson's charts depicts a stunning relationship between
animal protein consumption and the formation of kidney stones (Chart
10.4).32 It shows that consuming animal protein at levels above twenty-
o n e grams per person per day (slightly less than one ounce) for the
United Kingdom for the years of 1958 to 1973 is closely correlated with
a high number of kidney stones formed per 10,000 individuals per year.
This is an impressive relationship.
Few researchers have worked out the details of a research ques-
t i o n more thoroughly than Robertson and his colleagues. They have
developed a model for estimating the risk of stone formation with re-
markable accuracy.33 Although they have identified six risk factors for
kidney stones,34, 35 animal protein consumption was the major culprit.
Consumption of animal protein at levels commonly seen in affluent
countries leads to the development of four of the six risk factors ,34, 35
Not only is animal protein linked to risk factors for future formation
of stones, but it affects recurring stones as well. Robertson published
findings showing that, among the patients who had recurrent kidney
stones, he was able to resolve their problem simply by shifting their diet
away from animal protein foods,36