From: wheeler@super.org (Ferrell S. Wheeler)
Subject: China Study
Organization: Supercomputing Research Center (Bowie, MD)
Date: Fri, 11 Sep 1992 16:34:44 GMT


The New York Times   SCIENCE   Tuesday, May 8, 1990

Huge Study of Diet Indicts Fat and Meat

By JANE E. BRODY

In the `Grand Prix' of epidemiology, scientists tracked eating habits of
6,500 Chinese.


    Early findings from the most comprehensive large study ever
undertaken of the relationship between diet and the risk of developing
disease are challenging much of American dietary dogma.  The study,
being conducted in China, paints a bold portrait of a plant-based eating
plan that is more likely to promote health than disease.

    The study can be considered the Grand Prix of epidemiology.
Sixty-five hundred Chinese have each contributed 367 facts about their
eating and other habits that could ultimately help them and Americans
preserve their health and prolong their lives.  The data alone fill a
volume of 920 pages, to be published next month by Cornell University
Press.

    Among the first tantalizing findings are these:
    Obesity is related more to what people eat then how much.  Adjusted
for height, the Chinese consume 20 percent more calories than Americans
do, but Americans are 25 percent fatter.  The main dietary differences
are fat and starch.  The Chinese eat only a third the amount of fat
Americans do, while eating twice the starch.  The body readily stores
fat but expends a larger proportion of the carbohydrates consumed as
heat.  Some of the differences may be attributable to exercise.  The
varying levels of physical activity among the Chinese were measured, but
the data have not yet been analyzed.

    Reducing dietary fat to less than 30 percent of calories, as is
currently recommended for Americans, may not be enough to curb the risk
of heart disease and cancer.  To make a significant impact, the Chinese
data imply, a maximum of 20 percent of calories from fat -- and
preferably only 10 to 15 percent -- should be consumed.

    Eating a lot of protein, especially animal protein, is also linked
to chronic disease.  Americans consume a third more protein than the
Chinese do, and 70 percent of American protein comes from animals, while
only 7 percent of Chinese protein does.  Those Chinese who eat the most
protein, and especially the most animal protein, also have the highest
rates of the "diseases of affluence" like heart disease, cancer and
diabetes.

    A rich diet that promotes rapid growth early in life may increase a
woman's risk of developing cancer of the reproductive organs and the
breast.  Childhood diets high in calories, protein, calcium and fat
promote growth and early menarche, which in turn is associated with high
cancer rates.  Chinese women, who rarely suffer these cancers, start
menstruating three to six years later than Americans.  Dairy calcium is
not needed to prevent osteoporosis.  Most Chinese consume no dairy
products and instead get all their calcium from vegetables.  While the
Chinese consume only half the calcium Americans do, osteoporosis is
uncommon in China despite an average life expectancy of about 70 years,
just five few years less than the American average.

    These findings are only the beginning.  Dr. T. Colin Campbell, a
nutritional biochemist from Cornell University and the American
mastermind of the Chinese diet study, predicts that this "living
laboratory" will continue to generate vital findings for the next 40 to
50 years.

    The study, started in 1983 to explore dietary causes of cancer, has
been expanded to include heart, metabolic and infectious diseases.  Dr.
Chen Junshi of the Chinese Institute of Nutrition and Food Hygiene
organized the survey to cover locations from the semitropical south to
the cold, arid north.

Extracting, Labor-Intensive Study

    The extensive volume of raw data and its counterpart on computer
tape will be available to any scientist to use as raw material for
medical research.

    It is an exacting, labor-intensive study, initially financed by the
National Cancer Institute, that probably could not have been done
anywhere except China.  For nowhere else can accurate mortality
statistics be combined with data from people who live the same way in
the same place and eat the same foods for virtually their entire lives.

    Nowhere else is there a genetically similar population with such
great regional differences in disease rates, dietary habits and
environmental exposures.  For example, cancer rates can vary by a factor
of several hundred from one region of China to another.  These large
regional variations in China highlight biologically important
relationships between diet and disease.

`The Whole Diet Panoply'

    And nowhere else could researchers afford to hire hundreds of
trained workers to collect blood and urine samples and spend three days
in each household gathering exact information on what and how much
people eat, then analyzing the food samples for nutrient content.

    "The total cost in U.S. dollars of this project -- $2.3 million plus
600 person-years of labor contributed by the Chinese Government -- is a
mere fraction of what it would have cost to do the same study here,"
Dr. Campbell noted.  And unlike typically circumscribed American studies
that examine one characteristic as a factor in one disease, the Chinese
investigation "covers the whole diet panoply as it relates to all
diseases."

    Dr. Mark Hegsted, emeritus professor of nutrition at Harvard
University and former administrator of human nutrition for the United
States Department of Agriculture, said: "This is a very, very important
study -- unique and well done.  Even if you could pay for it, you
couldn't do this study in the United States because the population is
too homogeneous.  You get a lot more meaningful data when the
differences in diet and disease are as great as they are in the various
parts of China."

    In the first part of the study, 100 people from each of 65 counties
throughout China each contributed 367 items of information about their
diets, lives and bodies.  The responses from residents of each county
were then pooled to derive county wide characteristics that could be
measured against the area's death rates for more than four dozen
diseases.

    By matching characteristics, researchers derived 135,000
correlations, about 8,000 of which are expected to have both statistical
and biological significance that could shed light on the cause of some
devastating disease.

    In the poorer parts of China, infectious diseases remain the leading
causes of death, but in the more affluent regions, heart disease,
diabetes and cancer are most prominent, Dr. Campbell said.

Adding Taiwan to the Research

    Although from an overall perspective of nutrient composition the
Chinese diet is more health-promoting than ours, he said, there are some
important limitations that result from a lack of economic development.

    "Food quality and variety are not as good as ours," he explained.
"With limited refrigeration, bacteria and mold contamination is more
common, large amounts of salt and nitrites are used to preserve foods
and hot spices are used to mask off-flavors."

    The study is now being expanded and revised.  New mortality rates
are being gathered to update the original mortality data from the early
1970's and to reflect causes of death for 100 million people in the late
1980's.  The original 6,500 participants are being resurveyed and people
from 12 counties in Taiwan are being included in the expanded survey,
which will also measure many socioeconomic characteristics.

    "We want to see how economics change and health factors follow," Dr.
Campbell explained in an interview.  "Taiwan should be interesting
because it is intermediate between the United States and China in
nutrient intake and plasma cholesterol levels.  And since the
Taiwanese gene pool is more like the Chinese, we can study the relative
contributions of genetics and diet to risk of disease."

Cholesterol as Disease Predictor

    Dr. Campbell continued:  "So far we've seen that plasma
cholesterol is a good predictor of the kinds of diseases people are
going to get.  Those with higher cholesterol levels are prone to the
diseases of affluence -- cancer, heart disease and diabetes."

    Contrary to earlier reports that linked low blood cholesterol levels
to colon cancer, the Chinese study strongly suggests that low cholesterol
not only protects against heart disease but also protects against cancer
of the colon, the most common life-threatening cancer among Americans.
In China, mortality rates from colon cancer are lowest where cholesterol
levels are lowest.

    Over all, cholesterol levels in China, which rage from 88 to 165
milligrams per 100 milliliters of blood plasma, much lower than those in
the United States, which range from 155 to 274 milligrams per 100
milliliters of plasma.

    "Their high cholesterol is our low," Dr. Campbell noted.  He said
the data strongly suggest that a major influence on cholesterol levels
and disease rates is the high consumption of animal foods, including
dairy products, by Americans.

`Basically a Vegetarian Species'

    "We're basically a vegetarian species and should be eating a wide
variety of plant foods and minimizing our intake of animal foods." he
said.

    The Chinese have already begun to capitalize on these findings,
using them to develop national food and agricultural policies that will
promote health.

    "Usually, the first thing a country does in the course of economic
development is to introduce a lot of livestock," Dr. Campbell said.
"Our data are showing that this is not a very smart move, and the
Chinese are listening.  They're realizing that animal-based agriculture
is not the way to go."

    The plant-rich Chinese diet contains three times more dietary fiber
than Americans typically consume.  The average intake in China is 33
grams of fiber a day, and it ranges as high as 77 grams in some regions.
Dr. Campbell found no evidence to suggest that diets very high in fiber
are in any way deleterious to nutritional well-being.

    While American scientists worry that fiber may interfere with the
absorption of essential minerals like iron, no reason for concern was
found among the Chinese.  Rather, those with the highest fiber intake
also had the most iron-rich blood.

Iron From Vegetables

    The study also showed that consumption of meat is not needed to
prevent iron-deficiency anemia.  The average Chinese adult, who shows no
evidence of anemia, consumes twice the iron Americans do, but the vast
majority of it comes from the iron in plants.

    Nor are animal products needed to prevent osteoporosis, the study
showed.  "Ironically," Dr. Campbell noted, "osteoporosis tends to occur
in countries where calcium intake is highest and most of it comes from
protein-rich dairy products.  The Chinese data indicate that people need
less calcium than we think and can get adequate amounts from
vegetables."

    Another common health concern that could prove to be a red herring
is the fear that aflatoxin, which is produced by a mold that grows on
peanuts, corn and other grains, causes liver cancer.  Rather, the
Chinese study strongly indicates that chronic infection with hepatitis B
virus and high serum cholesterol levels are the primary culprits.

    Among other intriguing findings are a relationship between infection
with herpes simplex virus and coronary heart disease and a relationship
between infection with the yeast candida and nasopharyngeal cancer.


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