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WIDE-RANGING EFFECTS: BONE, KIDNEY, EYE, BRAIN DISEASES 205pause. It is often claimed to be due to an inadequate intake of calcium.
Therefore, health policy people often recommend higher calcium con-
sumption. 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-
thored 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 1880s^4
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-