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Background: Glycation reactions of proteins and other compounds, depending on blood glucose concentrations, have a detrimental effect on health. Objective: The association of diet and other lifestyle factors with glycated hemoglobin (Hb A1c) values was examined in a nondiabetic population. Design: This was a cross-sectional study of 1773 middle-aged men and women. Mean Hb A1c values were calculated for categories of diet and lifestyle factors, and odds ratios (ORs) for the highest versus lowest tertiles of Hb A1c were determined and compared. Results: The OR of being in the highest Hb A1c tertile compared with the lowest increased with greater age [age 40-44 y compared with >60 y: men (OR: 2.86; 95% CI: 1.60, 5.20) and women: (6.11; 3.15, 12.30)] and greater obesity [body mass index (in kg/m2) >25 and waist-hip ratio >1.0 in men and >0.8 in women): men (2.80; 1.48, 5.45) and women (1.73; 1.15, 2.61)]. High energy and energy-adjusted saturated fat intakes were associated with increased risk of being in the highest tertile of Hb A1c [highest compared with lowest quintile: (1.53; 1.04, 2.26; P for trend = 0.013) and (1.98; 1.33, 2.95; P for trend = 0.003), respectively]. No significant associations were observed for intakes of carbohydrates, protein, dietary fiber, or ß-carotene; however, some of the associations were nearly significant. Alcohol, vitamin C, and vitamin E intakes were inversely related to risk [highest compared with lowest quintile: (0.56; 0.38, 0.83; P for trend = 0.001), (0.50; 0.33, 0.74; P for trend = 0.003), and (0.65; 0.43, 0.96; P for trend = 0.036), respectively]. Conclusion: Hb A1c values might be modifiable by diet and other lifestyle factors. Copyright © 2000 American Society for Clinical Nutrition [ABSTRACT FROM AUTHOR]

Epidemiological studies suggest that tea drinking may reduce the risk of cardiovascular diseases and cancers. Although tea is an important source of antioxidant phytochemicals, variation in preparation techniques may translate to variation in antioxidant capacity. However, most large-scale epidemiological studies use regular food frequency questionnaires to estimate tea intake, and nationally available nutrient analysis databases do not include levels of black tea polyphenols. The Arizona Tea Questionnaire (ATQ) was designed as a tool for collecting more complete dietary tea consumption information, and a database was developed after analyzing 40 black tea samples (brewed, instant, and sun tea) for polyphenols. This study assesses the reliability and relative validity of the ATQ and polyphenol database. Relative validity of estimates of black tea consumption was tested by comparing the ATQ with the traditional Arizona Food Frequency Questionnaire and four days of food records. The ATQ was tested for reproducibility of estimates of black (hot and iced) tea consumption and levels of black tea polyphenol intake. Correlations between two measures of intake taken 2 months apart ranged from 0.72 for black hot tea to 0.86 for black sun tea. Mean intakes (range) of total flavonoids for black tea consumers were 80.8 (3.0-588.0) mg/day at the first ATQ and 102.4 (4.5-802.3) mg/day at the second ATQ (r = 0.83, P < 0.001). The ATQ provided highly reproducible estimates of both total tea consumption and individual tea polyphenol intake. This instrument may be a useful tool in studies of the associations between tea consumption, tea polyphenols intake, and risk for chronic disease.

Differences in tea drinking habits are likely to vary by populations and could contribute to the inconsistencies found between studies comparing tea consumption and cancer risk. A population-based case-control study was used to evaluate how usual tea consumption patterns of an older population (n = 450) varied with history of squamous cell carcinoma (SCC) of the skin. A detailed tea questionnaire was developed to assess specific tea preparation methods and patterns of drinking. In this southwestern United States population, black tea was the predominant variety of tea consumed. We found no association between the broad definition of any tea consumption and skin SCC. However, the adjusted odds ratios (ORs) for hot and iced black tea intake were 0.63 [95% confidence interval (CI), 0.36-1.10] and 1.02 (95% CI, 0.64-1.63), respectively. Controls were more likely to report usually drinking strong hot tea (OR, 0.74; 95% CI, 0.53-1.03) with increased brewing time (P for trend = 0.03). Adjusting for brewing time, the association between skin SCC and hot black tea consumption suggests a significantly lower risk in consumers of hot tea compared to nonconsumers (OR, 0.33; 95% CI, 0.12-0.87). This is one of the first studies to explore the relation between different types of tea consumption and occurrence of human cancers. Our results show that tea concentration (strength), brewing time, and beverage temperature have major influences on the potential protective effects of hot black tea in relation to skin SCC. Further studies with increased sample sizes are needed to evaluate the interrelationships between preparation techniques, tea type, and other life-style factors.

Aims: Phytic acid, a major constituent of cereals, pulses, and seeds has been advocated as an important antioxidant component of dietary fibre that affords possible protection against colorectal cancer. This is supported by experimental studies showing it has antineoplastic activity in animal models of both colon and breast cancer. To date the concentration of faecal phytic acid in human clinical groups has not been evaluated. Therefore the faecal phytic acid content of adenoma patients drawn from a placebo controlled calcium intervention trial was evaluated., Methods: Phytic acid was measured in faecal extracts by an improved ion-pair high performance liquid chromatography method., Results: Phytic acid was detected in the range 0.68-4.00 mumol/g wet faeces and 55-2038 mumol/day. Linear regression analyses showed no association between stool phytic acid and lipid content. Strong correlations were seen, however, between phytic acid and iron content, both on a concentration (r = 0.52; p = 0.00004) and daily excretion (r = 0.76; p = 5.5 x 10(-12) basis. Phytic acid was also strongly correlated with the daily excretion of calcium (r = 0.59; p = 1.36 x 10(-6) and magnesium (r = 0.42; p = 0.001). Cell proliferation in the sigmoid colon, an intermediate biomarker of colorectal cancer was not significantly associated with faecal phytic acid, minerals or lipid content in this compromised clinical group., Conclusions: This improved method, developed for the determination of phytic acid in faeces should allow further studies on the role of phytic acid in the aetiology of colorectal cancer to be conducted on a population or case control basis.

A longterm, double blind intervention trial was undertaken in patients with sporadic adenoma treated by polypectomy to investigate the putative role of calcium as a protective factor in colon carcinogenesis. The aim of the study was to assess the effect of a daily dietary supplementation of 2 g calcium over nine months on cell proliferation measured as proliferation index in colonic mucosa. A total of 48 patients were entered into the study of which 30 were fully compliant. After intervention proliferation index % (mean (SEM) in colonic epithelium was decreased in both the calcium (13.5 (1.5) to 11.4 (1.2)) and the placebo group (13.7 (0.9) to 10.8 (1.1)). The difference in the change between the two groups was not significant (p = 0.7). Changes in proliferation index % of crypt compartments were also not significantly different between the two groups. A significantly positive correlation between soluble calcium in faeces and the total proliferation index % in colonic epithelium at baseline and after intervention (r = 0.54, p < 0.01, r = 0.50, p < 0.01 respectively) suggests that an increase of free luminal calcium alone is insufficient for inhibition of cellular proliferation.

Calcium is purported to prevent colorectal cancer by forming insoluble complexes with bile acids and long-chain fatty acids in the large bowel. Therefore, a method for analysing calcium-lipid complexes in faeces has been developed to investigate this. The calcium soaps of a long-chain fatty acid (calcium palmitate) and bile acids (calcium deoxycholate, chenodeoxycholate, cholate and lithocholate) were obtained by organic synthesis. Studies with the authentic soaps reveal that they exist in an empirical ratio of calcium-to-lipid of 1:2. On addition to lipid-free faeces, approximately 30% of calcium palmitate could be recovered and quantified in the authentic state by extraction with 72% ethanol and overnight precipitation at 0 degree C. In contrast, the calcium soaps of the bile acids could not be recovered in the authentic state but were quantified entirely as the free acids. The method was applied to the analyses of calcium-lipid complexes in the faeces of adenoma patients partaking in a placebo-controlled calcium-intervention study. The results show that human faeces contain appreciable amounts of calcium long-chain fatty acid soaps predominantly in the form of calcium palmitate and stearate. The faecal concentration of long-chain fatty acid soaps was increased significantly (P = 0.005) during calcium intervention but this did not have a statistically significant effect on the excretion of free long-chain fatty acids (P = 0.4). Calcium long-chain fatty acid soap formation was found by multiple regression to be equally dependent on stool long-chain fatty acid and calcium concentration. Calcium soaps of the bile acids were not detected by this method.(ABSTRACT TRUNCATED AT 250 WORDS)

Measurements of cell proliferation can be used as biomarkers of preneoplastic change. In this study, two immunocytochemical methods that measure different components of the cell cycle were compared to assess cell proliferation on biopsy samples from human colonic mucosa. These methods are based on a monoclonal antibody against 5-bromo-2-deoxyuridine (BrdU), which is confined to S phase cells, and a more broad assessment of proliferation based on an antibody against proliferating cell nuclear antigen (PCNA, clone 19A2). In the PCNA assay, only strongly immunostained nuclei were included. The proliferation index was assessed in colonic mucosa from patients with no colonic disorders. Correlation between individual total proliferation indices determined by either method was significant with rs = 0.6 (p < 0.05). The mean proliferation index in the study group was 7.79% using BrdU and 7.64% using PCNA immunocytochemistry. Distribution of labelled cells within crypts was similar with respect to the two methods with a peak at the 18th and the 24th percentile in the case of BrdU and at the 23rd percentile for PCNA. Variance component analysis showed that at least two biopsy specimens should be evaluated per subject to allow a precise individual characterisation. It is concluded that PCNA (19A2) immunocytochemistry may be used as an operational marker of cell proliferation in normal colonic mucosa. A significant correlation and an agreement in the mean proliferation index between PCNA (19A2) and BrdU can only be achieved by a strictly standardised enumeration of labelled cells limited to strongly stained nuclei in the PCNA evaluation.