The Scoop on Plant-Based Diets.
|Article Type:||Brief Article|
Cookery, Asian (Health aspects)
Diet in disease (Research)
|Publication:||Name: Human Ecology Publisher: Cornell University, Human Ecology Audience: Academic Format: Magazine/Journal Subject: Health; Science and technology; Social sciences Copyright: COPYRIGHT 2001 Cornell University, Human Ecology ISSN: 1530-7069|
|Issue:||Date: Summer, 2001 Source Volume: 29 Source Issue: 3|
|Geographic:||Geographic Scope: Asia; China Geographic Name: China Geographic Code: 90ASI Asia|
THE LONG-TERM health benefits to Chinese and other Asian people who
have traditionally existed on a primarily plant-based diet might be lost
as more people in Asia switch to a Western-style diet that is rich in
That conclusion is being drawn by some scientists after reviewing results from the latest survey of diets, lifestyles, and disease mortality among Chinese populations-this one comparing current dietary habits in Taiwan and mainland China-and measuring them against a time when fewer meat and dairy products were available in rural China.
Preliminary results of China Study II, the follow-up to the China-Oxford-Cornell Study on Dietary, Lifestyle, and Disease Mortality Characteristics in 65 Rural Chinese Counties, or China Study I, were discussed on June 16 at the Congress of Epidemiology 2001 in Toronto.
"With the new data from mainland China, along with the fascinating new data from Taiwan now in hand, we will have the opportunity to explore dietary and disease mortality trends," says T. Colin Campbell, the Jacob Gould Schurman Professor Emeritus of Nutritional Biochemistry. "We will see how fast dietary changes in rural China--preceded by earlier changes in Taiwan-result in the development of Western diseases."
Some analyses of data from China Study I linked that population's low incidence of such Western health problems as cardiovascular disease, some cancers, obesity, and diabetes to plant-based diets that were low in animal products. China Study I is now regarded as the most comprehensive study of diet, lifestyle, and disease ever completed.
Planned since 1987, China Study II was designed to re-survey the same mainland Chinese population as China Study I, in addition to a few new sites in mainland China and a new population of 16 counties in Taiwan.
Both surveys afford an opportunity to investigate the effect of dietary change from the typical plant-based diet of rural China to a Western-style diet that includes more animal-based foods, as consumed in urban China and in Taiwan. "Even small increases in the consumption of animal-based foods was associated with increased disease risk," Campbell told a symposium at the epidemiology congress, pointing to several statistically significant correlations from the China studies:
* Plasma cholesterol in the 90- 170 milligrams per deciliter range is positively associated with most cancer mortality rates. Plasma cholesterol is positively associated with animal protein intake and inversely associated with plant protein intake.
* Breast cancer is associated with dietary fat (which is associated with animal protein intake) and inversely with age at menarche (women who reach puberty at younger ages have a greater risk of breast cancer).
* For those at risk for liver cancer (for example, because of chronic infection with hepatitis B virus) increasing intakes of animal-based foods and/or increasing concentrations of plasma cholesterol are associated with a higher disease risk.
* Cardiovascular diseases are associated with lower intakes of green vegetables and higher concentrations of apo-B (a form of so-called bad blood cholesterol), which is associated with increasing intakes of animal protein and decreasing intakes of plant protein.
* Colorectal cancers are consistently inversely associated with in-takes of 14 different dietary fiber fractions (although only one is statistically significant). Stomach cancer is inversely associated with green vegetable intake and plasma concentrations of beta-carotene and vitamin C obtained only from plant-based foods.
* Western-type diseases, in the aggregate, are highly significantly correlated with increasing concentrations of plasma cholesterol, which are associated in turn with increasing intakes of animal-based foods.
Analyses of data from the China studies are leading to policy recommendations. Campbell mentioned three:
* The greater the variety of plantbased foods in the diet, the greater the benefit. Variety insures broader coverage of known and unknown nutrient needs. * Provided there is plant food variety, quality, and quantity, a healthful and nutritionally complete diet can be attained without animal-based food.
* The closer the food is to its native state-with minimal heating, salting, and processing-the greater will be the benefit.
|Gale Copyright:||Copyright 2001 Gale, Cengage Learning. All rights reserved.|