Diet and chronic degenerative diseases: perspectives from China.

A comprehensive ecologic survey of dietary, life-style, and mortality characteristics of 65 counties in rural China showed that diets are substantially richer in foods of plant origin when compared with diets consumed in the more industrialized, Western societies. Mean intakes of animal protein (about one-tenth of the mean intake in the United States as energy percent), total fat (14.5% of energy), and dietary fiber (33.3 g/d) reflected a substantial preference for foods of plant origin. Mean plasma cholesterol concentration, at approximately 3.23-3.49 mmol/L, corresponds to this dietary life-style. The principal hypothesis under investigation in this paper is that chronic degenerative diseases are prevented by an aggregate effect of nutrients and nutrient-intake amounts that are commonly supplied by foods of plant origin. The breadth and consistency of evidence for this hypothesis was investigated with multiple intake-biomarker-disease associations, which were appropriately adjusted. There appears to be no threshold of plant-food enrichment or minimization of fat intake beyond which further disease prevention does not occur. These findings suggest that even small intakes of foods of animal origin are associated with significant increases in plasma cholesterol concentrations, which are associated, in turn, with significant increases in chronic degenerative disease mortality rates.

Association of dietary factors and selected plasma variables with sex hormone-binding globulin in rural Chinese women.

Sex hormone-binding globulin (SHBG) is an important regulator of plasma sex steroids as well as a sensitive indicator of insulin resistance. SHBG may be an important diagnostic measure of risk for pathologies associated with insulin resistance syndrome (IRS) such as non-insulin-dependent diabetes mellitus (NIDDM), obesity, hypertension, dyslipidemia, and atherosclerotic cardiovascular disease. In women, SHBG is also implicated in diverse pathologies such as cancers of steroid-sensitive tissues and hirsutism. Data from an ongoing ecological study linking diet and health in rural China were analyzed to determine the relation of selected plasma variables and diet to plasma concentrations of SHBG. All data represent county mean values, pooled by age and sex, to assess the relation between biochemical and lifestyle characteristics and disease-specific mortality rates at the county level. The study sample consisted of 3250 Chinese women between the ages of 35 and 64 y living in 65 widely dispersed rural counties. Consumption patterns for 21 different food groups were derived from a food-frequency questionnaire and a 3-d dietary survey and subsequently compared. Correlation analyses of county mean values demonstrated a significant association between SHBG and insulin, testosterone, triacylglycerols, body mass index, age at menarche, and several foods. In regression analyses, after adjustments, the strongest predictors of SHBG concentrations were the dietary intake of rice (beta = 0.42, P < 0.01), fish (beta = 0.34, P < 0.05), millet (beta = -0.27, P < 0.01), and wheat (beta = -0.34, P < 0.01). When insulin, testosterone, and triacylglycerols were added to the model only triacylglycerols (beta = -0.26, P < 0.05) remained a significant independent predictor of SHBG. Additional analyses suggested that the consumption of green vegetables was modestly positively correlated with SHBG and negatively with insulin values. Consumption of rice and fish in particular appeared to favorably influence the principle plasma variables associated with a reduction in the risk for IRS pathologies.

Molecular epidemiology of aflatoxin exposures: validation of aflatoxin-N7-guanine levels in urine as a biomarker in experimental rat models and humans.

Human epidemiology and experimental animal data have provided the statistical association and biological information necessary to propose that aflatoxins are risk factors for human liver cancer. As liver cancer causes at least 200,000 deaths per year, prevention measures must be developed to ameliorate this nearly always fatal disease. Preventive strategies will be facilitated by the identification of individuals at high risk. It is the goal of the molecular dosimetry field to provide facile and accurate biomarkers to identify people at high risk for carcinogen exposure and consequent adverse health effects. We have developed methods to defect the major aflatoxin DNA adduct, aflatoxin N7-guanine (AFB-N7-guanine), in urine, examined the dose-response characteristics in people living in China and The Gambia, and have found an excellent association of this biomarker with exposure. In addition to exposure studies in people, our laboratories have monitored AFB-N7-guanine excretion in the urine of rats whose risk for developing cancer has been modulated with dietary chemoprotective agents such that independent groups of animals receiving the same dosage of aflatoxin B1 were at either high or low risk for tumorigenesis. The production of DNA damage by aflatoxins is not the exclusive mechanism for liver cancer. Many other factors, including hepatitis B virus, cell proliferation, and nutritional status, can exert strong modification effects in human disease. Thus, molecular epidemiological investigations that examine only one biomarker may greatly underestimate or overestimate the risk for an individual.(ABSTRACT TRUNCATED AT 250 WORDS)