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-
shine 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