Dietary changes and disease transition in China.

Abstract

The patterns of food consumption in China have changed substantially over the past two decades, along with the continuous development of the national economy. From 1978 to 1987, the national food disappearance data showed a 2-fold increase in meat consumption, a 2.8-fold increase in egg consumption, and a 2.9-fold increase in fat and oil consumption.1 The same trend was clearly seen from the national nutrition survey data. Between 1982 and 1992, the national consumption of cereals and tubers decreased by 12 and 47% respectively, whereas meat, egg, and fat/ oil consumption increased by 38, 60, and 61%, respectively.2 The contribution of fat to the total dietary energy reached 28.4% in 1992, and in big cities like Beijing, Shanghai, and others, energy from fat has exceeded 30% of the total energy intake.2 The major dietary changes in China are the rapid increase of animal product and fat/oil consumption and, at the same time, the slight decrease of cereal and tuber consumption, although the average dietary pattern in China still consists mainly of a plant-food-based diet. On the other hand, China is also undergoing a rapid epidemiologic transition, that is a shift from a disease pattern dominated by infectious and deficiency diseases to an epidemic of non-communicable chronic diseases which will eventually dominate. Although nutritional deficiency diseases and infectious diseases have not been eradicated, these conditions are now largely confined to certain economic and age groups, and particular regions. At the same time, however, death from cancer, cardiovascular and cerebrovascular disease, and morbidity from diabetes, osteoporosis, and so on are increasing rapidly. By 1996, 66% of the total deaths in China were caused by chronic diseases, and in urban areas this figure was 76%.3 The main causes of death now in urban China are cancer, cardiovascular and cerebrovascular disease, and respiratory disease. The health implications of these dietary changes could be further illustrated by some results from a collaborative ecologic study on diet, lifestyle, and disease mortality.4 The study was carried out in 130 villages in 65 counties of rural China. A wide variety of dietary, lifestyle, and biochemical characteristics were recorded for a total of 6500 subjects, ages 35–64 y. Several relevant examples of study results will be presented here. Example 1: Based on the correlation of mortality between specific diseases, the diseases were geographically clustered into two groups, i.e., one associated with poor economic development—diseases of poverty (e.g., infectious diseases), and the other associated with the emergence of more wealth— diseases of affluence (e.g., most chronic diseases).5 It was found that the chief correlate of the latter disease group was plasma cholesterol (r 5 0.48, P , 0.01), even though the average county mean was only 127 mg/dL, ranged from 86 to 181 mg/ dL.4 Further analysis of the same data showed that the plasma cholesterol level was positively correlated with the consumption of meat (r 5 0.26, P , 0.05) and total fat (r 5 0.27, P , 0.05), and inversely correlated with the consumption of certain dietary fiber fractions, such as total neutral detergent fiber (r 5 20.34, P , 0.01).5 Example 2: Plasma Apo B was directly associated with mortality from coronary heart disease (r 5 0.39, P , 0.01); in turn, Apo B was significantly positively associated with animal protein intake (r 5 0.25, P , 0.05) and frequency of meat intake (r 5 0.32, P , 0.01), but significantly inversely associated with plant protein intake (r 5 20.37, P , 0.01) and selected carbohydrate intake, such as starch (r 5 20.40, P , 0.01) and pectin (r 5 20.26, P , 0.05).5 A repeat survey in the same 65 counties in 1989 showed that within 6 y the average contribution of dietary fat intake to the total dietary energy increased from 15 to 20%. At the same time, the average plasma total cholesterol level in males increased from 127 to 142 mg/dL, and in females from 127 to 143 mg/dL. It is quite obvious that this rapid epidemic transition is mainly caused by life-