Meat consumption, cooking practices, meat mutagens, and risk of prostate cancer

Consumption of red meat, particularly well-done meat, has been associated with increased prostate cancer risk. High-temperature cooking methods such as grilling and barbecuing may produce heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs), which are known carcinogens. We assessed the association with meat consumption and estimated HCA and PAH exposure in a population-based case-control study of prostate cancer. Newly diagnosed cases aged 40-79 years (531 advanced cases, 195 localized cases) and 527 controls were asked about dietary intake, including usual meat cooking methods and doneness levels. Odds ratios (OR) and 95% confidence intervals (CI) were calculated using multivariate logistic regression. For advanced prostate cancer, but not localized disease, increased risks were associated with higher consumption of hamburgers (OR = 1.79, CI = 1.10-2.92), processed meat (OR = 1.57, CI = 1.04-2.36), grilled red meat (OR = 1.63, CI = 0.99-2.68), and well-done red meat (OR = 1.52, CI = 0.93-2.46), and intermediate intake of 2-amino-1-methyl1-6-phenylimidazo[4,5-b]pyridine (PhIP) (Quartile 2 vs. 1: OR = 1.41, CI = 0.98-2.01; Quartile 3 vs. 1: OR = 1.42, CI = 0.98-2.04), but not for higher intake. White meat consumption was not associated with prostate cancer. These findings provide further evidence that consumption of processed meat and red meat cooked at high temperature is associated with increased risk of advanced, but not localized, prostate cancer.     

Meat cooking habits and risk of colorectal cancer in Córdoba, Argentina

OBJECTIVE: Colorectal cancer is the third cause of death among women and the fifth among men in Córdoba, Argentina. We previously reported colorectal cancer to be associated with a high intake of fatty meats and bovine viscera and inversely associated with dietary fiber intake. In this study, we investigated the role of method of cooking meat and preferences in browned surfaces in the risk of colorectal cancer. METHODS: A case-control retrospective study was carried out by interviewing 296 patients and 597 control subjects with a food-frequency questionnaire. Meat consumption and preferred cooking procedures (boiled, roasted, barbecued, cooked in a flat iron-pan without fat, and fried) were investigated. Odds ratios and 95% confidence intervals were obtained by unconditional logistic regression analysis. RESULTS: Barbecuing was the cooking method preferred by men, whereas iron-pan cooking was favored by women; frying was the least favored method. Fatty beef, sausages, and bovine viscera were preferentially barbecued or boiled, whereas lean beef was mainly roasted, iron-pan cooked, or fried. Chicken was barbecued or roasted. The multivariate relative risks (adjusted by age, sex, social stratum, and total energy intake) for preferring darkly browned surfaces were significantly associated with an increased risk for all cooking procedures (odds ratio, 4.57; 95% confidence interval, 3.10 to 6.73). No associations were found for red roasted or for boiled meats. CONCLUSION: Increased risk seems to be related to cooking temperature and close contact of the food to the heating source, because higher risks were observed for heavily browned surfaces when meats were barbecued or iron-pan cooked.     

Well-Done Meat Intake,Heterocyclic Amine Exposure,and Cancer Risk

High intake of meat, particularly red and processed meat, has been associated with an increased risk of a number of common cancers such as breast, colorectum, and prostate in many epidemiological studies. Heterocyclic amines (HCAs) are a group of mutagenic compounds found in cooked meats, particularly well-done meats. HCAs are some of most potent mutagens detected using the Ames/salmonella tests and have been clearly shown to induce tumors in experimental animal models. Over the past 10 years, an increasing number of epidemiological studies have evaluated the association of well-done meat intake and meat carcinogen exposure with cancer risk. The results from these epidemiologic studies were evaluated and summarized in this review. The majority of these studies have shown that high intake of well-done meat and high exposure to meat carcinogens, particularly HCAs, may increase the risk of human cancer.     

天津市区胃癌危险因素的配对病例对照研究

目的 进一步探讨各危险因素与胃癌的关系。方法 选取天津市市内六区1998年和1999年的189例新发胃癌病人并按性别、年龄、民族等配比条件选取该市189名健康人群进行1：1配对的病例对照研究,资料处理采用条件logistic回归分析。结果 多因素条件logistic回归分析显示胃癌的发病与下列4种因素关节密切：烟熏食品OR=2.34,95%CI：1.60-4.98;吸烟量OR=6.07,95%CI：1.26-7.16;喜食重盐饮食OR=1.95,95%CI：1.27-3.23;过量摄入动物肉类OR=1.46,95%CI：1.05-2.02。结论 经常食用烟熏食品、吸烟量大、喜食重盐饮食、过量摄入动物肉类可能是胃癌的危险因素。     

Fruits, vegetables, soy foods and breast cancer in pre- and postmenopausal Korean women: a case-control study

We carried out a case-control study to examine the relationship between fruits, vegetables, and soy foods intake with breast cancer risk in Korean women. Incident cases (n = 359) were identified through cancer biopsies and hospital-based controls (n = 708) were selected in the same hospitals. Subjects were asked to indicate usual dietary habits, which were assessed using a semi-quantitative food frequency questionnaire (98 items). Odds ratio (OR) and 95% confidence intervals (95% CI) were calculated by unconditional logistic regression after adjustment for additional confounding factors according to the menopausal status. High grape intake showed an inverse association of breast cancer in postmenopausal women (OR = 0.59, 95% CI = 0.35-0.95; p for trend = 0.05). High tomato intake was associated with reduced breast cancer risk in premenopausal women (OR = 0.59, 95% CI = 0.38-0.89, p for trend = 0.04). In postmenopausal women, green pepper intake showed an inverse association of breast cancer risk (OR = 0.60, 95% CI = 0.43-0.96, p for trend = 0.03). High soybean intake showed an inverse association of breast cancer in postmenopausal women (OR = 0.61, 95% CI = 0.34-0.89, p for trend = 0.02). Our study suggests that high intake of some fruits, vegetables, and soybeans may be associated with a reduced breast cancer risk.     

Polymorphisms in Xenobiotic Metabolizing Genes,Intakes of Heterocyclic Amines and Red Meat,and Postmenopausal Breast Cancer

Heterocyclic amines (HCAs) are mutagenic compounds generated when meats are cooked at high temperature and for long duration. The findings from previous studies on the relation between HCAs and breast cancer are inconsistent, possibly because of genetic variations in the enzymes metabolizing HCAs. To evaluate whether the associations of intakes of estimated HCAs, meat-derived mutagenicity (MDM), and red meat with risk of postmenopausal breast cancer were modified by N-acetyltransferase 2 (NAT2) acetylator genotype or cytochrome P450 1A2-164 A/C (CYP1A2) polymorphism, we conducted a nested case-control study with 579 cases and 981 controls within a prospective cohort, the Nurses’ Health Study. HCAs and MDM intakes were derived using a cooking method questionnaire administered in 1996. NAT2acetylator genotype, the CYP1A2 polymorphism, and intakes of HCAs, MDM, and red meat were not associated with risk of postmenopausal breast cancer. There was also no interaction between NAT2 acetylator genotype or CYP1A2 polymorphism and HCAs and MDM and red meat intake in relation to breast cancer. These results do not support the hypothesis that genetic polymorphisms of xenobiotic enzymes involved in the metabolism of HCAs may modify the associations between intakes of red meat or meat-related mutagens and breast cancer risk.     

Meat consumption and risk of stomach cancer in Uruguay: a case-control study

We previously reported an association between meat intake and stomach cancer in Uruguay: in that analysis, we did not control for total energy intake. To better study the relationship between intake of meat and meat constituents and gastric cancer, we conducted a further case-control study including 123 cases and 282 controls who were enrolled between September 1997 and August 1999. Total meat intake (highest tertile) was associated with an odds ratio (OR) of 4.6 [95% confidence interval (CI) = 2.3-9.0]. After adjustment for total energy intake and intake of proteins and total fat by the residuals method, the OR was 1.7 (95% CI = 0.7-4.0). The energy-adjusted OR for high intake of processed meat was 1.9 (95% CI = 1.1-3.5). Intake of fried, barbecued, and salted meat and 2-amino-1-methyl-6-phenyl-imidazo[4,5-b]pyridine was not associated with risk of gastric cancer. The energy-adjusted OR of high intake of nitrosodimethylamine was 1.5 (95% CI = 0.9-2.8). These results suggest that, in a country with elevated meat consumption, total energy intake and intake of proteins and fat are powerful confounders in the relationship between meat intake and gastric cancer risk. However, a modest independent effect of meat, in particular of processed meat, is suggested.     

Heterocyclic amines,meat intake,and association with colon cancer in a population-based study

The authors examined the association between colon cancer and meat intake categorized by level of doneness, cooking method, and estimated levels of heterocyclic amines (HCAs), benzo[a]pyrene, and mutagenicity. Data were collected as part of a population-based, case-control study of colon cancer in North Carolina between 1996 and 2000 that included 701 African-American (274 cases, 427 controls) and 957 White (346 cases, 611 controls) participants. Odds ratios were calculated by using unconditional logistic regression, comparing the fifth to the first quintile levels of intake or exposure. Intake of red meat was positively associated with colon cancer (odds ratio (OR) = 2.0, 95% confidence interval (CI): 1.3, 3.2). Associations with meat intake by cooking method were strongest for pan-fried red meat (OR = 2.0, 95% CI: 1.4, 3.0). Associations with meat intake by doneness were strongest for well-/very well done red meat (OR = 1.7, 95% CI: 1.2, 2.5). The strongest association for individual HCAs was reported for 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (DiMeIQx) across all levels of exposure, with odds ratios of 1.8-2.0. Overall, sophisticated exposure measures were used to report modest, positive associations between red meat intake and colon cancer consistent with the hypothesis that HCAs may be among the etiologically relevant compounds in red meat.     

Cigarette smoking and breast cancer.

An epidemiological case-control study was conducted in New York State, with 1617 primary breast cancer patients and an equal number of controls, to examine the relationship between cigarette smoking and breast cancer. Results showed no overall association between ever smokers versus never smokers and breast cancer risk (odds ratio [OR] = 1.03, 95% confidence interval [CI]: 0.90-1.19), nor was there any dose response trend observed with increased levels of smoking. In addition, no association was found with risk and age started smoking, age stopped smoking, amount smoked or total years smoked. Controlling for previously identified risk factors for breast cancer in the analysis did not significantly alter these relationships. Previous studies have found a difference in menopausal age among smokers compared to nonsmokers. The mean menopausal age was only slightly lower in smokers than in never smokers for both cases and controls. Breast cancer risk was observed to be close to unity for premenopausal women (OR = 0.97, 95% CI: 0.74-1.34) and postmenopausal women (OR = 1.06, 95% CI: 0.91-1.26). A recent study suggested breast cancer risk was more strongly related to starting smoking at a young age among women who smoked at least 25 or more cigarettes per day in the most recent year of smoking. This hypothesis was not supported by these data.     

Impact of barbecued meat consumed in pregnancy on birth outcomes accounting for personal prenatal exposure to airborne polycyclic aromatic hydrocarbons: Birth cohort study in Poland

ObjectiveWe previously reported an association between prenatal exposure to airborne polycyclic aromatic hydrocarbons (PAH) and lower birth weight, birth length, and head circumference. The main goal of the present analysis was to assess the possible impact of coexposure to PAH-containing barbecued meat consumed during pregnancy on birth outcomes.Materials and methodsThe birth cohort consisted of 432 pregnant women who gave birth at term (>36 wk of gestation). Only non-smoking women with singleton pregnancies, 18–35 y of age, and who were free from chronic diseases such as diabetes and hypertension, were included in the study. Detailed information on diet over pregnancy was collected through interviews and the measurement of exposure to airborne PAHs was carried out by personal air monitoring during the second trimester of pregnancy. The effect of barbecued meat consumption on birth outcomes (birth weight, length, and head circumference at birth) was adjusted in multiple linear regression models for potential confounding factors such as prenatal exposure to airborne PAHs, child's sex, gestational age, parity, size of mother (maternal prepregnancy weight, weight gain in pregnancy), and prenatal environmental tobacco smoke.ResultsThe multivariable regression model showed a significant deficit in birth weight associated with barbecued meat consumption in pregnancy (coeff = ?106.0 g; 95%CI: ?293.3, ?35.8). The effect of exposure to airborne PAHs was about the same magnitude order (coeff. = ?164.6 g; 95%CI: ?172.3, ?34.7). Combined effect of both sources of exposure amounted to birth weight deficit of 214.3 g (95%CI: ?419.0, ?9.6). Regression models performed for birth length and head circumference showed similar trends but the estimated effects were of borderline significance level. As the intake of barbecued meat did not affect the duration of pregnancy, the reduced birth weight could not have been mediated by a shortened gestation period.ConclusionIn conclusion, the study results provided epidemiologic evidence that prenatal PAH exposure from diet including grilled meat might be hazardous for fetal development.     

Usual Cruciferous Vegetable Consumption and Ovarian Cancer: A Case-Control Study

Ovarian cancer is the fifth leading cause of cancer-related deaths among women, primarily due to diagnosis at late stages. Therefore, identification of modifiable risk factors for this disease is warranted. Using the Patient Epidemiology Data System (PEDS), collected from 1981 to 1998 at Roswell Park Cancer Institute, Buffalo, NY, we conducted a hospital-based, case-control analysis of self-reported cruciferous vegetable intake and ovarian cancer among 675 women with primary, incident ovarian cancer, and 1275 without cancer. Cruciferous vegetable intake was queried using a 44-item food frequency questionnaire (FFQ). Odds ratios (OR) and 95% confidence intervals (CI) were estimated with logistic regression, adjusting for age, body mass index (BMI), education, smoking status, parity, family history of ovarian cancer, total fruit consumption, total meat consumption, and total noncruciferous vegetable consumption. We observed a significant inverse association for women with highest vs. lowest intakes of total vegetables (OR = 0.65, 95% CI = 0.46–0.92), cooked cauliflower (OR = 0.82, 95% CI = 0.67–0.99), and cooked greens (OR = 0.63, 95% CI = 0.46–0.86) and an inverse, dose-dependent association between cooked cruciferous vegetables intake and ovarian cancer (for each additional ten servings per month, OR = 0.85, 95% CI = 0.76–0.96). These findings suggest that a diet that includes cruciferous vegetables could be an important modifiable risk factor for ovarian cancer.     

Case-control study of lifetime physical activity and breast cancer risk

A population-based case-control study of 1,233 incident breast cancer cases and 1,237 controls was conducted in Alberta, Canada, in 1995-1997 to examine the effect of lifetime physical activity patterns on breast cancer risk. No associations between physical activity and breast cancer were found for premenopausal women. For postmenopausal women in the highest quartile (> or =161 metabolic equivalent (MET)-hours/week per year) versus the lowest quartile (<104.8 MET-hours/week per year) of lifetime total physical activity, the adjusted odds ratio was 0.70 (95% confidence interval (CI): 0.52, 0.94). When the risks associated with each type of activity were examined for postmenopausal women, household and occupational activity conferred the largest risk reductions (odds ratio (OR) = 0.57, 95% CI: 0.41, 0.79 and OR = 0.59, 95% CI: 0.44, 0.81, respectively, for highest vs. lowest quartiles of activity), while recreational activity was not associated with any risk reductions. For postmenopausal women, the authors found stronger risk reductions for those who were also nonsmokers (OR = 0.64, 95% CI: 0.46, 0.88), non-alcohol-drinkers (OR = 0.39, 95% CI: 0.11, 0.77), or nulliparous (OR = 0.22, 95% CI: 0.07, 0.70) when they compared the highest with the lowest quartile of lifetime total physical activity. This study provides evidence that lifetime total activity reduces risk of postmenopausal breast cancer.     

Cruciferous vegetables, the GSTP1 Ile105Val genetic polymorphism, and breast cancer risk

BACKGROUND: Cruciferous vegetables are the primary source of isothiocyanates and other glucosinolate derivatives that are known to induce phase II detoxifying enzymes, including glutathione S-transferases (GSTs). OBJECTIVE: We investigated the independent and combined effects of cruciferous vegetable intake and the GSTP1 Ile(105)Val genetic polymorphism on breast cancer risk. DESIGN: Analyses included 3035 cases and 3037 population controls who were participating in the Shanghai Breast Cancer Study and for whom diet and genetic data were complete (87% of cases and 85% of controls). RESULTS: With the use of multivariate logistic regression, the GSTP1 Val/Val genotype was significantly associated with greater breast cancer risk (OR = 1.50; 95% CI: 1.12, 1.99). The association was significantly greater in premenopausal women (OR = 1.69; 95% CI: 1.17, 2.43) than in postmenopausal women (OR = 1.20; 95% CI: 0.74, 1.92). Total cruciferous vegetable intake was not significantly associated with breast cancer risk, although subjects reporting greater turnip (P for trend < 0.001) and Chinese cabbage (P for trend = 0.049) intakes had a significantly lower postmenopausal breast cancer risk. Women with the GSTP1 Val/Val genotype and low cruciferous vegetable intake had a breast cancer risk 1.74-fold (95% CI: 1.13, 2.67) that of women with the Ile/Ile or Ile/Val genotype. This effect of low cruciferous vegetable intake and the Val/Val genotype was seen predominantly among premenopausal women (OR = 2.08; 95% CI = 1.20, 3.59). CONCLUSIONS: Cruciferous vegetable intake consistent with high isothiocyanate exposure may reduce breast cancer risk. Cruciferous vegetable intake also may ameliorate the effects of the GSTP1 genotype.     

Effects of Dietary Fiber,Fats, and Meat Intakes on the Risk of Barrett's Esophagus

Animal and human models suggest associations between fat intake, fiber intake, and the risk of esophageal adenocarcinoma. We evaluated whether these factors may act early in the carcinogenic pathway as a risk factor for Barrett's esophagus, a potentially premalignant precursor to esophageal adenocarcinoma using a case-control design within the Kaiser Permanente, Northern California population. Incident Barrett's esophagus cases (n = 296) were matched to persons with gastroesophageal reflux disease (GERD) (n = 308) and to population controls (n = 309). Higher intakes of omega-3-fatty-acids [cases vs. population controls; OR = 0.46, 95% CI = 0.22–0.97, 4th vs. 1st quartiles of intake], polyunsaturated fat, total fiber (OR = 0.34, 95% CI = 0.15–0.76), and fiber from fruits and vegetables (OR = 0.47 95% CI = 0.25–0.88) were associated with a lower risk of Barrett's esophagus. Higher meat intakes were associated with a lower risk of long-segment Barrett's esophagus (OR = 0.25, 95% CI = 0.09–0.72). In contrast, higher trans-fat intakes were associated with increased risk (OR = 1.11; 95% CI = 1.03–1.21 per g/day). Total fat intake, barbecued foods, and fiber intake from sources other than fruits and vegetables were not associated with Barrett's esophagus. Future studies to evaluate whether dietary interventions might influence the risk of Barrett's esophagus or esophageal adenocarcinoma in high risk persons are needed.     

Raw and cooked vegetables, fruits, selected micronutrients, and breast cancer risk: a case-control study in Germany

In 1998-2000, a case-control study of breast cancer was conducted in Heidelberg, Germany. Three hundred ten consecutively recruited cases with primary breast cancer were matched according to 10-yr age groups to 353 controls with conditions unrelated to diet or endocrine disorders. Intake of raw vegetables, total vegetables, and whole-grain products was inversely associated with breast cancer risk (highest vs. lowest quartile adjusted odds ratio [OR] 0.51, 95% confidence interval [CI] 0.31-0.84; OR = 0.62, 95% CI = 0.38-1.02; and OR = 0.57; 95% CI = 0.34-0.95, respectively). Also, high intake of some selected vitamins and minerals possessing putative DNA-stabilizing properties displayed significant inverse risk associations. Adjusted ORs were as follows: vitamin C (OR = 0.49, 95% CI = 0.2-0.88), folate equivalents (OR = 0.47, 95% CI = 0.25-0.88), b-carotene (OR = 0.46, 95% CI = 0.27-0.80), zinc (OR = 0.35, 95% CI = 0.15-0.78), and copper (OR = 0.51, 95% CI = 0.31-1.03). In contrast, no significant association with risk was seen for an increased intake of fruits, cooked vegetables, fiber, calcium, manganese, or iron. In this population of German women, components of raw vegetables and some micronutrients appear to decrease breast cancer risk.     

Red Meat-Derived Heterocyclic Amines Increase Risk of Colon Cancer: A Population-Based Case-Control Study

Formation of mutagenic heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs) is one pathway believed to drive the association of colon cancer with meat consumption. Limited data exist on the associations of individual HCAs and PAHs in red or white meat with colon cancer. Analyzing data from a validated meat preparation questionnaire completed by 1062 incident colon cancer cases and 1645 population controls from an ongoing case-control study, risks of colon cancer were estimated using unconditional logistic regression models, comparing the fourth to the first quartile of mutagen estimates derived from a CHARRED based food frequency questionnaire. Total dietary intake of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) [adjusted odds ratio (aOR) = 1.87, 95% confidence interval (CI) = 1.44–2.44, P _trend < 0.0001], 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (DiMeIQx) (aOR = 1.68, 95% CI = 1.29–2.17, P _trend = 0.001) and meat-derived mutagenic activity (aOR = 1.77, 95% CI = 1.36–2.30, P _trend < 0.0001) were statistically significantly associated with colon cancer risk. Meat type specific analyses revealed statistically significant associations for red meat-derived MeIQx, DiMeIQx, and mutagenic activity but not for the same mutagens derived from white meat. Our study adds evidence supporting red meat-derived, but not white-meat derived HCAs and PAHs, as an important pathway for environmental colon cancer carcinogenesis.     

The effect of rosemary on the mutagenic activity of heterocyclic amines extracted from common food consumed in Saudi Arabia

Meat intake may increase cancer risk as heterocyclic amines (HCAs) are one of the food mutagens produced in meat cooked at high temperature. The consumption of meat in Saudi Arabia is high compared with other developing countries and the incidence of cancer has been increasing during the past 30 years. The present study aimed to quantitatively determine the effect of rosemary on the mutagenic activity and the amount of HCAs formed in beef Shawerma, grilled chicken and fried liver as an attempt to minimize the carcinogenic risk of HCAs formed in these commonly consumed meat dishes. Surprisingly, rosemary extracts (2%, 5%, 10% and 15%) apparently enhanced the total amount of HCAs measured in beef Shawerma, whereas 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) was the only mutagenic amine inhibited by 2% rosemary with a reduction up to 61.6% compared with control. In grilled chicken, the total amount of HCAs measured in 2% rosemary samples was reduced seven-fold lower than the control level, whereas PhIp and 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (TrpP1) were inhibited to non-detectable levels. These data demonstrate that 2% rosemary may play an important role in attenuating the production of PhIP in both Shawerma and fried chicken. In fried liver, HCAs were not detected either in the control or in 2% treated samples whereas augmented levels of TrpP1 were measured in 5%, 10% and 15% rosemary. The mutagenic activity of HCAs extracted from all beef Shawerma and grilled chicken treated samples increased over the control sample using Salmonella typhimurium TA100. In fried liver, the mutagenic activity detected in the control sample was higher than treated samples, which suggests that S. typhimurium TA100 might be less sensitive in detecting the mutagenic response of TrpP1 extracted from the real food system. We believe more research is needed to assess the role of antioxidants in the formation of HCAs in order to optimize both safety and quality of our diets.     

Carnosine concentration of ingested meat affects carnosine net release into the portal vein of minipigs

Because of its physiological effects, carnosine (beta-alanyl-L-histidine) can be considered as a bioactive food component. The objective of this study was to assess the quantitative significance of intact carnosine absorption after ingestion of different beef meats, using the minipig as animal model. In a preliminary experiment, we evaluated the level of dietary carnosine in intestinal digesta of pigs (n = 4) after a meat meal (0.94 g protein/kg body weight) of grilled top loin (TL) or stewed shoulder (S). In accordance with meat carnosine concentration (20.7 and 7.2 micromol/g for TL and S, respectively), intestinal carnosine concentration was greater for TL than S. For both meats, carnosine flow to mid-jejunum was almost completed in the first 3 h following intake, and about one-half of the ingested carnosine disappeared from the intestinal lumen before the mid-jejunum. In catheterized minipigs (n = 4), we assessed the portal net release of dietary carnosine after a meat meal (1.4 g protein/kg body weight) of TL, S, and a blend of grilled neck and brisket (NB; 12.2 micromol carnosine/g). Postprandial carnosine plasma concentration and portal net release were not affected after an S meal, but they increased, proportionally to meat carnosine content, with NB and TL. For these meats, carnosine net release throughout the whole postprandial period accounted for 22% of the ingested carnosine. These results indicated that meat carnosine can be absorbed across the intestinal wall and that carnosine bioavailability depends on carnosine content of cooked meat.     

Serum polychlorinated biphenyls, cytochrome P-450 1A1 polymorphisms, and risk of breast cancer in Connecticut women

Recent epidemiologic studies have suggested that genetic polymorphisms in the cytochrome P-450 1A1 gene (CYP1A1) may affect the relation between environmental exposure to polychlorinated biphenyls (PCBs) and breast cancer risk. The authors report results from a case-control study evaluating the potential effect of gene-environment interaction between CYP1A1 and serum PCB levels on breast cancer risk among Caucasian women in Connecticut. The study included 374 case women with histologically confirmed breast cancer and 406 noncancerous controls with information on both serum PCB level and CYP1A1 genotype (1999-2002). Compared with women who had the homozygous wild-type CYP1A1 m2 genotype, significantly increased risks of breast cancer were found for women with the CYP1A1 m2 variant genotype (odds ratio (OR) = 2.1, 95% confidence interval (CI): 1.1, 3.9), especially postmenopausal women (OR = 2.4, 95% CI: 1.1, 5.0). Risks associated with the CYP1A1 m2 variant genotype were highest for all women (OR = 3.6, 95% CI: 1.5, 8.2) and postmenopausal women (OR = 4.3, 95% CI: 1.6, 12.0) with higher serum PCB levels (611-2,600 ng/g). The CYP1A1 m1 and m4 genotypes were not associated with breast cancer risk independently or in combination with PCB exposure. In summary, the CYP1A1 m2 genetic polymorphism was associated with increased risk of female breast cancer and may modify the relation between PCB exposure and breast cancer risk.     

Characterization of meat consumption and risk of colorectal cancer in Cordoba,Argentina

BACKGROUND: The Argentinean food pattern, rich in beef and fats and poor in fibers, may be related to an risk of increased colorectal cancer (CRC). To examine the relation between CRC risk and meat type, we carried out a case-control study in Córdoba, Argentina. METHODS: We interviewed 287 patients with colorectal adenocarcinomas and 566 control subjects admitted to the largest hospitals in greater Córdoba. Dietary habits were assessed by a food-frequency questionnaire, and different meat types were evaluated. Regression analyses determined the contribution of meat to total energy and macronutrients. Unconditional multiple logistic regression was performed to calculate odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Median intake of all meats, predominantly bovine, was high, reaching almost 300 g/d in men. Meats provided approximately 50% of total energy intake and 64% to 67% of total protein. Patients obtained significantly more cholesterol and total lipids from meats than did controls. Consumption of total meat, red meat, and other types of meat were not related to increased risk of CRC. However, an increased risk of CRC was found for those consuming relatively large amounts of cold cuts and sausages (OR, 1.47; CI, 1.02-2.15) and bovine viscera (OR, 1.73; CI, 1.18-2.54). Lean beef was associated with a decreased risk of CRC at the second (OR, 0.64; CI, 0.43-0.94) and third (OR, 0.67; CI, 0.40-0.97) tertiles. CONCLUSIONS: Red meat produced a different pattern of risk according to its fat content. Further studies should assess the possible role of cooking meat and other non-nutritional components.