208 THE CHINA STUDYwomen 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-
sumed 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-
mal-to-plant 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-
sumption countries, is due to dairy foods, rather than calcium supple-
ments 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.