The China Study
The authors argue that "most, but not all, of the
confusion about nutrition is created in legal, fully disclosed ways and is
disseminated by unsuspecting, well-intentioned people, whether they are
researchers, politicians or journalists," and that there are powerful
industries that stand to lose a lot if Americans shift to a plant base diet.
They write that those industries "do everything in their power
to protect their profits and their shareholders.
They argue that earlier studies of nutrition
(particularly the well-known Nursed' Health Study, which began in 1976) were
flawed because they focused on the effects of varying amounts of individual
nutrients among people who were consuming a uniformly high-risk, carnivorous
(animal-based) diet They write that "hardly any study has done
more damage to the nutritional landscape than the Nurses' Health Study,"
and that it should "serve as a warning for the rest of science for what not
to do.”
Background to the China-Cornell-Oxford Project
The China-Cornell-Oxford Project—the
"China-Oxford-Cornell Study on Dietary, Lifestyle and Disease Mortality
Characteristics in 65 Rural Chinese Counties," called in the book
"the China Study"—was a comprehensive study of dietary and lifestyle
factors associated with disease mortality in China, which compared the health
consequences of diets rich in animal-based foods to diets rich in plant-based
foods among people who are genetically similar.
The idea for the study began in 1980–81, during
discussions between T. Colin Campbell at his laboratory in Cornell and Chen
Junshi, Deputy Director of Institute of Nutrition and Food Hygiene at the
Chinese Academy of Preventive Medicine. They were later joined by Richard
Peto of the University of Oxford – Professor of Medical Statistics and
Epidemiology as of 2012 – and Li Junyao of the China Cancer Institute.
In 1983, two villages were chosen at random in each of
65 rural counties in China and 50 families were chosen at random in each village.
The dietary habits of one adult member of each family were examined – half
male, half female – and the results compared to the death rates in those
counties from around 48 forms of cancers and other diseases during 1973–75.
"Western" diseases correlated to
concentration of blood cholesterol
The study included a comparison of the prevalence of
Western diseases (coronary heart disease, diabetes, Leukemia , and
cancers of the colon, lung, breast, brain, stomach and liver) in each county,
using 1973–75 death rates. The study collected diet and lifestyle
variables (ignoring all other factors) from inhabitants of the same counties
approximately 10 years later, and found that, as blood cholesterol levels
rose, so did the prevalence of "Western" diseases recorded in those
counties in 1973–75.
The study linked lower blood cholesterol levels to
lower rates of heart disease and cancer. As blood cholesterol levels decreased
from 170 mg/dl to 90 mg/dl, the authors write that cancers of the
liver, rectum, colon, lung, breast, childhood and adult leukemia, brain,
stomach and esophagus(throat) decreased. Rates for some cancers varied by a
factor of 100 from those counties with the highest rates to the counties with
the lowest rates.
The authors write that "as blood cholesterol
levels in rural China rose in certain counties the incidence of 'Western'
diseases also increased. What made this so surprising was that Chinese levels
were far lower than we had expected. The average level of blood cholesterol was
only 127 mg/dl, which is almost 100 points less than the American average
(215 mg/dl). ...Some counties had average levels as low as 94 mg/dl.
...For two groups of about twenty-five women in the inner part of China,
average blood cholesterol was at the amazingly low level of 80 mg/dl."
Blood cholesterol levels correlated to diet,
particularly animal protein
The authors write that "several studies have now
shown, in both experimental animals and in humans, that consuming animal-based
protein increases blood cholesterol levels. Saturated fat and dietary
cholesterol also raise blood cholesterol, although these nutrients are not as
effective at doing this as is animal protein. In contrast, plant-based foods
contain no cholesterol and, in various other ways, help to decrease the amount
of cholesterol made by the body." They write that "these disease
associations with blood cholesterol were remarkable, because blood cholesterol
and animal-based food consumption both were so low by American standards. In
rural China, animal protein intake (for the same individual) averages only 7.1
grams per day whereas Americans average 70 grams per day."
They conclude that "the findings from the China
Study indicate that the lower the percentage of animal-based foods that are
consumed, the greater the health benefits—even when that percentage declines
from 10% to 0% of calories.
Mechanisms of action
Plants protect the body from disease, they argue,
because many of them contain both a large concentration of and a large variety
of antioxidants, which protect the body from damage caused by free radicals.
Western diseases are correlated with
growth, which is associated with the increased risk of initiation,
promotion and progression of disease, and that growth is correlated with a diet
high in animal protein. They argue that the consumption of animal protein
increases the acidity of blood and tissues and that to neutralize this
acid,calcium (a very effective base) is pulled from the bones. They also
state that higher concentrations of calcium in the blood inhibit the
process by which the body activates vitamin D in the kidneys to calcitriol, a
form that helps regulate the immune system.
The China study book could be find at;http://books.google.com/books/about/The_China_study.html?id=KgRR12F0RPAC
