Meat Intake In Relation Research Articles

Red and White Meat Intake in Relation to Gut Flora in Obese and Non-Obese Arab Females.

high meat intake may contribute to several chronic diseases including obesity. However, evidence is insufficient on the relation between red/white meat intake and gut flora among individuals with varying degrees of adiposity. investigate the association of red/white meat intake with gut flora in Saudi Arabian females with/without obesity. this observational study involved 92 females with and without obesity (n = 44, 48, respectively) aged 19-25 years. The whole-genome shotgun technique was used to analyze the gut flora. Shannon alpha and Bray-Curtis beta diversity as well as correlation coefficients were used. in the total sample, there were positive correlations between Actinobacteria, Bacteroides (p ≤ 0.05), Flavonifractor plautii (p ≤ 0.0001), and total red meat intake. There were also positive correlations between total white meat intake, Bacteroides, and Faecalibacterium prausnitzii (p ≤ 0.05) in the total sample. In the group without obesity, there was a positive correlation between low white meat intake and Actinobacteria (p = 0.05). In the group with obesity, there was a positive correlation between high white meat intake and Bacteroides (p ≤ 0.001). our findings suggest that meat intake had an impact on the gut flora of Arab adult females, independent of adiposity. Specific strains identified in this study need further investigation to determine their relation to meat intake and obesity.

Red and White Meat Intake in Relation to Gut Flora in Obese and non-Obese Arab Females

Red and White Meat Intake in Relation to Gut Flora in Obese and non-Obese Arab Females

A Prospective Analysis of Red and Processed Meat Intake in Relation to Colorectal Cancer in the Black Women's Health Study

BackgroundBlack Americans have the highest incidence of colorectal cancer (CRC) of any racial/ethnic group in the United States. High intake of red and processed meats has been associated with an increased CRC risk in predominately White populations. However, 3 prior studies in Black populations, who have been reported to have high intakes of red and processed meats, have reported no associations. Data on a possible association between CRC risk and SFAs and MUFAs, the primary types of fat in red and processed meats, are inconclusive. ObjectivesWe prospectively assessed intakes of processed and unprocessed red meat, SFAs, and MUFAs in relation to CRC risk, utilizing data from the Black Women's Health Study (BWHS, 1995–2018). MethodsDietary data were derived from validated FFQs completed in 1995 and 2001. Multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards regression. ResultsAmong 52,695 BWHS participants aged 21–69 y at baseline and followed for ≤22 y, 564 women developed incident CRC. Unprocessed red meat intake was associated with a 33% increased CRC risk per 100 g/d (HR: 1.33; 95% CI: 1.03–1.71). Examination of CRC anatomic sites revealed that unprocessed red meat was associated with 2-times increased rectal cancer risk (HR: 2.22; 95% CI: 1.15–4.26). There was no evidence of an interaction with age (pinteraction = 0.4), but unprocessed red meat intake was only associated with a significant increased risk of late-onset CRC (≥50 y of age, HR: 1.41; 95% CI: 1.05–1.88). Processed red meat and total SFA and MUFA intakes were not associated with CRC risk. ConclusionsUnprocessed red meat intake was associated with an increased CRC risk in the present study, the first positive evidence that red meat plays a role in the etiology of CRC in Black women. The findings suggest prevention opportunities.

Red and Processed Meat Intake in Relation to Non-Alcoholic Fatty Liver Disease Risk: Results from a Case-Control Study.

Data on the association between dietary red meat intake and non-alcoholic fatty liver disease (NAFLD) are limited. We designed this case-control study to determine the association between red and processed meat consumption and risk of NAFLD in Iranian adults. A total of 999 eligible subjects, including 196 NAFLD patients and 803 non-NAFLD controls were recruited from hepatology clinics in Tehran, Iran. A reliable and validated food frequency questionnaire was used to evaluate the red and processed meat intakes. The analyzes performed showed that in an age- and gender-adjusted model, patients with the highest quartile of red meat intake had an approximately three-fold higher risk of NAFLD than those with the lowest quartile of intake (odds ratio [OR], 3.42; 95% confidence interval [CI], 2.16–5.43; p value < 0.001). Moreover, patients in the highest quartile of processed meat intake had a 3.28 times higher risk of NAFLD, compared to the lowest quartile(OR, 3.28; 95% CI, 1.97–5.46; p value < 0.001).Both these associations remained significant by implementing additional adjustments for body mass index, energy intake, dietary factors, diabetes, smoking, and physical activity (OR, 3.65; 95% CI, 1.85–7.18; p value < 0.001 and OR, 3.25; 95% CI, 1.57–6.73; p value = 0.002, respectively).Our findings indicate that both red and processed meat intakes are related to the increased odds of NAFLD; however, prospective studies are needed to confirm these results.

Red and White Meat Intake in Relation to Mental Disorders in Iranian Adults.

Background: The association between meat consumption and mental disorders is less investigated in Iranian population. We examined the association between meat consumption and prevalence of symptoms of depression, anxiety, and psychological distress in Iranian adults.Methods: This cross-sectional study included 3,362 participants aged 18–55 years old. A dish-based 106-item semiquantitative food frequency questionnaire (FFQ) was used to assess usual dietary intake of study population. Hospital Anxiety and Depression Scale (HADS) and General Health Questionnaire (GHQ), all validated in Iranian population, were applied to collect data on symptoms of anxiety, depression, and psychological distress, respectively.Results: The prevalence of symptoms of depression, anxiety, and psychological distress in the study population was 28.6, 13.6, and 22.6%, respectively. After considering potential confounders, individuals in the top quartile of red meat intake had 43% increased risk of depression symptoms [odds ratio (OR) = 1.43; 95% CI: 1.09–1.89] compared to those in the first quartile. No significant relation was observed between red meat intake and anxiety or psychological distress symptoms. White meat consumption was not associated with mental disorders. Stratified analysis by sex showed that male participants in the highest quartile of red meat intake had 92% greater risk of depression symptoms (95% CI: 1.17–3.15) than those individuals in the lowest category. Red and white meat intake was not associated with mental disorders in women. In overweight or obese individuals, despite lack of any association between red meat intake and mental disorders, high intake of white meat was associated with a lower odds of psychological distress symptoms (OR = 0.64; 95% CI: 0.42–0.99) and a lower risk of depression symptoms (OR = 0.68; 95% CI: 0.45–1.00). In normal-weight participants, those in the highest quartile of red meat intake had greater odds for depression symptoms than those in the lowest quartile (OR = 1.66; 95% CI: 1.14–2.42).Conclusions: We found that red meat consumption was associated with increased risk of depression symptoms, especially in men, and normal-weight participants. In overweight or obese participants, white meat intake was inversely associated with psychological distress symptoms.

A Prospective Analysis of Red and Processed Meat Intake in Relation to Colorectal Cancer Incidence in the Black Women’s Health Study

Abstract Objectives African Americans have the highest incidence of colorectal cancer (CRC) of any racial/ethnic group in the US. High intake of red and processed meats has been shown to increase CRC risk in populations of European ancestry, but evidence in African American populations is limited. The association between saturated and monounsaturated fatty acid intakes, the primary types of fat in red and processed meat, and CRC is inconclusive. Thus, we prospectively assessed the intake of red and processed meats and dietary saturated and monounsaturated fatty acids in relation to CRC risk, utilizing the Black Women's Health Study (BWHS, 1995–2018). Methods Dietary data were derived from validated food frequency questionnaires completed in 1995 and 2001 by 52,695 BWHS participants. Multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards regression adjusted for energy, fiber, and discretionary fat. Results Over a median follow-up of 22 years, 564 women developed incident CRC. Total red meat intake was associated with a 25% increased risk of CRC per 100 g/day (HR = 1.25; 95% CI: 0.94–1.66), which was primarily due to intake of unprocessed red meat (HR = 1.33, 95% CI: 1.05–1.70). Processed meat and total saturated and monounsaturated fatty acid intakes were not associated with an increased risk of CRC. Conclusions Unprocessed red meat intake was associated with an increased risk of CRC in this cohort of African American women. The strong evidence, now including African American women, that red meat plays a role in the etiology of CRC suggests opportunities for prevention. Funding Sources This research was funded by National Institutes of Health grants U01 CA164974 and R01 CA058420, the Karin Grunebaum Cancer Research Foundation, and the Boston University Peter Paul Career Development Professorship.

Processed meat intake in relation to semen quality indicators among men attending a fertility clinic

AbstractIt is estimated that in Central and Eastern Europe 8–12% of men are infertile, and in the case of 20% of infertile couples in the region, indicates a 56% part of the malefactor in the occurrence of infertility. Numerous studies have shown that a healthy diet with a high intake of fish and seafood, poultry, vegetables, fruits, legumes, through the high content of antioxidants are associated with better parameters of semen quality and reduced risk of asthenozoospermia. Men's diets may affect spermatogenesis as reflected in semen quality indicators, but the literature on the relation between meat intake and semen quality is limited. Our objective was to prospectively examine the relation between meats including red, poultry, proceesed and fish and indicators of semen quality. Men in subfertile couples presenting for evaluation at the Olsztyn Hospital Fertility Center were invited to participate in an ongoing study of environmental factors and fertility. This cross-sectional study was carried out in 208 men aged 18–55 years from Northern-Eastern Poland. Semen samples were collected at the clinic and analyses were performed by an experienced technician. Semen microscopic measurements were determined with the use of computer-aided semen analysis (CASA) and evaluated according to the World Health Organization (WHO) guidelines. A total of men completed a validated food-frequency questionnaire and subsequently provided semen samples. We used linear mixed regression models to examine the relation between meat intake and semen quality indicators (total sperm count, sperm concentration, progressive motility, morphology, and semen volume) while adjusting for potential confounders. After adjustment for age, BMI, physical activity, residence place and education, one serving increase in intake of processed meat was associated with a 56% higher risk of abnormal progressive sperm motility (OR = 1.56 95%CI:1.09–2.21). Consuming processed meat may have a negative impact on sperm counts and morphology. Potentially, these products may be a significant source of saturated and trans fatty acids, xenobiotics, mainly xenoestrogen, and steroids. Is need to clarify the potential effect of meat products, especially processed meat, on male reproductive potential in RCTs or longitudinal studies. Future findings may be useful to establish a more precise recommendation connected with red and processed meat intake in the context of reproductive health.

Meat intake and risk of colorectal polyps: results from a large population-based screening study in Germany ,

Background: Red and processed meats have been shown to be associated with colorectal adenomas in many, but not all, studies, and the association according to the type of colorectal adenoma or the location in the colorectum is unclear.Objectives: We investigated the association of meat intake in relation to colorectal polyps and further investigated the association according to histologic subtypes and subsites in a large population-based screening study in Germany.Design: In this cross-sectional study, 15,950 participants aged ≥55 y underwent a screening colonoscopy. We calculated prevalence ratios (PRs) and 95% CIs for associations between meat intake and the most-advanced findings from a colonoscopy with the use of log binomial regression.Results: Overall, 3340 participants (20.4%) had nonadvanced adenomas, 1643 participants (10.0%) had advanced adenomas, and 189 participants (1.2%) had colorectal cancer. We observed no statistically significant association between red or processed meat consumption and the prevalence of any adenomas or advanced adenomas [highest compared with lowest: red meat, PR: 1.07 (95% CI: 0.83, 1.37); processed meat, PR: 1.11 (95% CI: 0.91, 1.36)]. In site-specific analyses, although no dose-response relation was observed, processed meat was positively associated with the prevalence of advanced adenomas in the rectum only (multiple times per day compared with <1 time/wk, PR: 1.87; 95% CI: 1.19, 2.95). Poultry intake was not associated with any outcome.Conclusions: On the basis of this large colonoscopy-based study, there are no significant associations between red or processed meat intake and the prevalence of any adenomas or advanced adenomas. However, processed meat may be positively associated with the prevalence of advanced adenomas in the rectum, but prospective cohort studies are needed to further clarify this association. There is no association between poultry consumption and the prevalence of colorectal polyps in this study.

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.

Low ABCB1 Gene Expression Is an Early Event in Colorectal Carcinogenesis

The ABCB1/MDR1 gene product ABCB1/P-glycoprotein is implicated in the development of colorectal cancer (CRC). NFKB1 encodes transcription factors regulating expression of a number of genes including ABCB1. We have previously found association between the ABCB1 C-rs3789243-T polymorphism and CRC risk and interactions between the ABCB1 C-rs3789243-T and C3435T polymorphisms and meat intake in relation to CRC risk (Andersen, BMC Cancer, 2009, 9, 407). ABCB1 and NFKB1 mRNA levels were assessed in intestinal tissue from 122 CRC cases, 101 adenoma cases (12 with severe dysplasia, 89 with mild-moderate dysplasia) and from 18 healthy individuals, together with gene polymorphisms in ABCB1 and NFKB1. ABCB1 mRNA levels were highest in the healthy individuals and significantly lower in mild/moderate and severe dysplasia tissue (P<0.05 for both), morphologically normal tissues close to the tumour (P<0.05), morphologically normal tissue at a distance from the tumour (P<0.05) and CRC tissue (P<0.001). Furthermore, ABCB1 mRNA levels were lower in adenomas and carcinomas compared to morphologically normal tissue from the same individuals (P<0.01). The ABCB1 C-rs3789243-T and NFKB1 -94ins/del homozygous variant genotypes were associated with low ABCB1 mRNA levels in morphologically normal sigmoid tissue from adenoma cases (P<0.05 for both). NFKB1 mRNA levels were lower in both tumour and normal tissue from cancer patients (P<0.001) as compared to healthy individuals but we were unable to show association between NFKB1 -94ins/del genotype and NFKB1 mRNA levels. This study suggests that low ABCB1 mRNA levels are an early event in CRC development and that the two polymorphisms affect ABCB1 mRNA levels whereas low NFKB1 mRNA levels occur later in carcinogenesis. Low ABCB1 protein levels may promote colorectal carcinogenesis through increasing intracellular exposure to carcinogenic ABCB1 substrates.

Systematic review: diet–gene interactions and the risk of colorectal cancer

BackgroundDiet contributes significantly to colorectal cancer (CRC) aetiology and may be potentially modifiable.AimTo review diet–gene interactions, aiming to further the understanding of the underlying biological pathways in CRC development.MethodsThe PubMed and Medline were systematically searched for prospective studies in relation to diet, colorectal cancer and genetics.ResultsIn a meta-analysis, no interaction between NAT1 phenotypes and meat intake in relation to risk of CRC was found (P-value for interaction 0.95). We found a trend towards interaction between NAT2 phenotypes and meat intake in relation to risk of CRC. High meat intake was not associated with risk of CRC among carriers of the slow NAT2 phenotype, whereas NAT2 fast acetylators with high meat intake were at increased risk of CRC (OR = 1.25; 95% confidence interval (CI): 0.92–2.01) compared with slow acetylators with low meat intake (reference), P-value for interaction = 0.07. Low meat intake in the studied populations may influence the result. Interactions between meat, cruciferous vegetables, fibres, calcium, vitamins, and alcohol and ABCB1,NFKB1,GSTM1, GSTT1, CCND1, VDR, MGTM, IL10 and PPARG are suggested.ConclusionsA number of interactions between genetic variation and diet are suggested, but the findings need replication in independent, prospective, and well-characterised cohorts before conclusions regarding the underlying biological mechanisms can be reached. When the above criteria are met, studies on diet–gene interactions may contribute valuable insight into the biological mechanisms underlying the role of various dietary items in colorectal carcinogenesis.

Red and processed meat consumption and risk of stroke: a meta-analysis of prospective cohort studies

Epidemiological evidence is suggestive, but inconclusive, for an association between consumption of red and processed meat and risk of stroke. We aimed to assess this association by conducting a meta-analysis of prospective cohort studies. We performed a literature search on PubMed database through June 2012 to identify prospective cohort studies of red and processed meat intake in relation to risk of stroke. Reference lists of the retrieved articles were also reviewed. Both fixed-effects and random-effects model were assumed to compute the summary risk estimates. Five large independent prospective cohort studies were identified. These studies contained a total of 2 39 251 subjects and 9593 stroke events. Comparing the highest category of consumption with lowest category, the pooled relative risks (RRs) of total stroke were 1.15 (95% confidence interval (CI), 1.05-1.25) for total meat (red and processed meat combined) (n=4), 1.09 (95% CI, 1.01-1.18) for red meat (n=5) and 1.14 (95% CI, 1.05-1.25) for processed meat (n=5); the corresponding RRs of ischemic stroke (highest vs lowest quintile) were 1.15 (95% CI, 1.04-1.28), 1.13(95% CI, 1.01-1.25) and 1.19 (95% CI, 1.08-1.31). Consumption of red and/or processed meat was not associated with hemorrhagic stroke. In the dose-response analysis, the risk of stroke increased significantly by 10% and 13% for each 100 g per day increment in total and red meat consumption, respectively, and by 11% for each 50 g per day increment in processed meat consumption. Findings from this meta-analysis indicate that consumption of red and/or processed meat increase risk of stroke, in particular, ischemic stroke.

Long-term dietary heme iron and red meat intake in relation to endometrial cancer risk

Heme and total iron, present in meat, have been hypothesized to promote carcinogenesis. Few prospective studies have examined the associations between intakes of heme and total iron, types of meat, and endometrial cancer risk. We evaluated the associations between intakes of heme and total iron, types of meat, and risk of endometrial cancer in a large cohort of women. Among 60,895 women in the Swedish Mammography Cohort, 720 endometrial cancer cases were confirmed during 21 y of follow-up. RRs and 95% CIs were calculated by Cox proportional hazards models. A comparison of the highest with the lowest quartile showed a 20-30% higher risk of endometrial cancer for higher intakes of heme iron (RR: 1.24; 95% CI: 1.01, 1.53 for ≥1.63 compared with <0.69 mg/d), total iron (RR: 1.31; 95% CI: 1.07, 1.61 for ≥15.09 compared with <12.27 mg/d), and liver (RR: 1.29; 95% CI: 1.06, 1.56 for ≥100 compared with <100 g/wk). No statistically significant associations were observed between intakes of red and processed meats and endometrial cancer risk. RRs did not greatly differ when we stratified by BMI, parity, and intakes of alcohol, vitamin C, or zinc or when we excluded patients with diabetes. Our study suggests a modest positive association between heme iron, total iron, and liver intakes and endometrial cancer risk; no statistically significant associations were observed for intakes of other red and processed meats and endometrial cancer risk.

Abstract B110: Polymorphisms in xenobiotic metabolizing genes, intakes of heterocyclic amines and red meat, and postmenopausal breast cancer

Abstract Background: Heterocyclic amines (HCAs) are mutagenic compounds generated when meats are cooked at high temperature and for long duration. Evidence from animal studies has pointed towards a possible role of HCAs in breast carcinogenesis. However, findings from previous studies on HCAs and breast cancer are inconsistent, possibly due to genetic variations in the enzymes metabolizing HCAs. Methods: 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 (NAT 2) 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 (NHS). HCAs and MDM intakes were derived using a cooking method questionnaire administered in 1996. Results: NAT2 acetylator 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 and HCAs and MDM and red meat intake in relation to breast cancer. There was no interaction between the CYP1A2 genotype and HCAs and MDM and red meat intake in relation to breast cancer. Conclusion: 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 risk of breast cancer. Citation Information: Cancer Prev Res 2011;4(10 Suppl):B110.

Polymorphisms in NFkB, PXR, LXR and risk of colorectal cancer in a prospective study of Danes

BackgroundTranscription factors and nuclear receptors constitute a link between exposure to heterocyclic amines and polycyclic aromatic hydrocarbons from meat and tobacco smoke and colorectal cancer (CRC) risk. The aim of this study was to investigate if polymorphisms in nuclear factor kappa-B, pregnane X receptor, and liver X receptor were associated with risk of CRC, and to investigate possible interactions with lifestyle factors such as smoking, meat consumption, and NSAID use.MethodsThe polymorphisms nuclear factor kappa-B (NFkB, NFKB1) -94 insertion/deletion ATTG (rs28362491), pregnane X receptor (PXR, NR1I2) A-24381C (rs1523127), C8055T (rs2276707), A7635G (rs6785049), liver X receptor (LXR-β, NR1H3) C-rs1405655T, T-rs2695121C were assessed together with lifestyle factors in a nested case-cohort study of 378 CRC cases and 756 random participants from the Danish prospective Diet, Cancer and Health study of 57,053 persons.ResultsCarriers of NFkB -94deletion were at 1.45-fold higher risk of CRC than homozygous carriers of the insertion allele (incidence rate ratio (IRR) = 1.45, 95% confidence interval (95% CI): 1.10-1.92). There was interaction between this polymorphism and intake of red and processed meat in relation to CRC risk. Carriers of NFkB -94deletion were at 3% increased risk pr 25 gram meat per day (95% CI: 0.98-1.09) whereas homozygous carriers of the insertion were not at increased risk (p for interaction = 0.03). PXR and LXR polymorphisms were not associated with CRC risk. There was no interaction between use of nonsteroid antiinflammatory drugs (NSAID) or smoking status and NFkB, PXR or LXR polymorphisms.ConclusionsA polymorphism in NFkB was associated with CRC risk and there was interaction between this polymorphism and meat intake in relation to CRC risk. This study suggests a role for NFkB in CRC aetiology.

Polymorphisms in the xenobiotic transporter Multidrug Resistance 1 (MDR1) and interaction with meat intake in relation to risk of colorectal cancer in a Danish prospective case-cohort study

BackgroundThe xenobiotic transporters, Multidrug Resistance 1 (MDR1/ABCB1) and Breast Cancer Resistance Protein (BCRP/ABCG2) may restrict intestinal absorption of various carcinogens, including heterocyclic amines (HCA) and polycyclic aromatic hydrocarbons (PAH). Cyclooxygenase-2 (COX-2) derived prostaglandins promote gastrointestinal carcinogenesis, affecting angiogenesis, apoptosis, and invasiveness.The aim of this study was to investigate if polymorphisms in these genes were associated with risk of colorectal cancer (CRC), and to investigate possible interactions with lifestyle factors such as smoking, meat consumption, and NSAID use.MethodsThe following polymorphisms were analyzed; a synonymous MDR1 C3435T (rs1045642) in exon26, G-rs3789243-A in intron3, the functional BCRP C421A (rs2231142), the two COX-2 A-1195G (rs689466) and G-765C (rs20417) in the promoter region, and the COX-2 T8473C (rs5275) polymorphisms in the 3'-untranslated region. The polymorphisms were assessed together with lifestyle factors in a nested case-cohort study of 359 cases and a random cohort sample of 765 participants from the Danish prospective Diet, Cancer and Health study.ResultsCarriers of the variant allele of MDR1 intron 3 polymorphism were at 1.52-fold higher risk of CRC than homozygous wild type allele carriers (Incidence rate ratio (IRR) = 1.52, 95% Confidence Interval (CI): 1.12-2.06). Carriers of the variant allele of MDR1 C3435T exon 26 had a lower risk of CRC than homozygous C-allele carriers (IRR = 0.71 (CI:0.50-1.00)). There was interaction between these MDR1 polymorphisms and intake of red and processed meat in relation to CRC risk. Homozygous MDR1 C3435T C-allele carriers were at 8% increased risk pr 25 gram meat per day (CI: 1.00-1.16) whereas variant allele carriers were not at increased risk (p for interaction = 0.02). COX-2 and BCRP polymorphisms were not associated with CRC risk. There was interaction between NSAID use and MDR1 C3435T and COX-2 T8473C (p-values for interaction 0.001 and 0.04, respectively).ConclusionTwo polymorphisms in MDR1 were associated with CRC risk and there was interaction between these polymorphisms and meat intake in relation to CRC risk. Our results suggest that MDR1 polymorphisms affect the relationship between meat and CRC risk.

Long-term meat intake and risk of breast cancer by oestrogen and progesterone receptor status in a cohort of Swedish women

Red meat intake has been postulated to increase the risk of breast cancer but epidemiologic studies have yielded inconsistent results. Data on meat intake in relation to hormone receptor-defined breast cancer are sparse. We examined the association of meat intake with incidence of breast cancer defined by oestrogen receptor (ER) and progesterone receptor (PR) status in the Swedish Mammography Cohort, a population-based cohort of 61,433 women. Dietary intake was assessed at baseline in 1987–1990 and again in 1997. Cox proportional hazards models were used to estimate relative risks for the association between long-term meat intake and breast cancer risk. During a mean follow-up of 17.4 years, 2952 incident cases of invasive breast cancer were ascertained. We found no association of total red meat, fresh red meat or processed meat intake with breast cancer risk. The multivariate relative risks (95% confidence interval) for the highest quintile of total red meat intake (⩾98 g/d) compared with the lowest quintile (<46 g/d) were 0.98 (0.86–1.12) for overall breast cancer, 1.10 (0.90–1.34) for ER+/PR+ tumours, 0.86 (0.60–1.23) for ER+/PR– tumours and 1.12 (0.70–1.79) for ER–/PR– tumours. Intake of pan-fried meat was positively associated with a risk of ER+/PR– tumours; the multivariate relative risk for the highest compared with the lowest quartile of intake was 1.45 (95% confidence interval 1.03–2.03; P trend = 0.03). These results do not support an association between red meat intake and overall breast cancer risk but suggest that fried meat intake may increase the risk of ER+/PR– breast cancer.

Dietary Meat Intake in Relation to Colorectal Adenoma in Asymptomatic Women

No previous study has concurrently assessed the associations between meat intake, meat-cooking methods and doneness levels, meat mutagens (heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons), heme iron, and nitrite from meat and colorectal adenoma in asymptomatic women undergoing colonoscopy. Of the 807 eligible women in a cross-sectional multicenter colonoscopy screening study, 158 prevalent colorectal adenoma cases and 649 controls satisfactorily completed the validated food frequency and meat questionnaires. Using an established meat mutagen database and new heme iron and nitrite databases, we comprehensively investigated the components of meat that may be involved in carcinogenesis. Using logistic regression, we estimated odds ratios (ORs) and 95% confidence intervals (CIs) within quartiles of meat-related variables. Red meat was associated positively with colorectal adenoma (OR fourth vs. first quartile = 2.02; 95% CI = 1.06-3.83; P trend = 0.38). Intake of pan-fried meat (OR = 1.72; 95% CI = 0.96-3.07; P trend = 0.01) and the HCA: 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) (OR = 1.90; 95% CI = 1.05-3.42; P trend = 0.07) were also associated with an increased risk of colorectal adenoma. The new databases yielded lower estimates of heme iron and nitrite than previous assessment methods, although the two methods were highly correlated for both exposures. Although not statistically significant, there were positive associations between iron and heme iron from meat and colorectal adenoma. In asymptomatic women undergoing colonoscopy, colorectal adenomas were associated with high intake of red meat, pan-fried meat, and the HCA MeIQx. Other meat-related exposures require further investigation.

A Prospective Study of Red and Processed Meat Intake in Relation to Cancer Risk

BackgroundRed meat and processed meat have been associated with carcinogenesis at several anatomic sites, but no prospective study has examined meat intake in relation to a range of malignancies. We investigated whether red or processed meat intake increases cancer risk at a variety of sites.Methods and FindingsThe National Institutes of Health (NIH)-AARP (formerly the American Association for Retired Persons) Diet and Health Study is a cohort of approximately 500,000 people aged 50–71 y at baseline (1995–1996). Meat intake was estimated from a food frequency questionnaire administered at baseline. Cox proportional hazards regression was used to estimate hazard ratios and 95% confidence intervals within quintiles of red and processed meat intake. During up to 8.2 y of follow-up, 53,396 incident cancers were ascertained. Statistically significant elevated risks (ranging from 20% to 60%) were evident for esophageal, colorectal, liver, and lung cancer, comparing individuals in the highest with those in the lowest quintile of red meat intake. Furthermore, individuals in the highest quintile of processed meat intake had a 20% elevated risk for colorectal and a 16% elevated risk for lung cancer.ConclusionsBoth red and processed meat intakes were positively associated with cancers of the colorectum and lung; furthermore, red meat intake was associated with an elevated risk for cancers of the esophagus and liver.

Epoxide hydrolase polymorphisms, cigarette smoking and risk of colorectal adenoma in the Nurses' Health Study and the Health Professionals Follow-up Study.

Microsomal epoxide hydrolase (mEH) is involved in the bioactivation and detoxification of polycyclic aromatic hydrocarbons derived from tobacco smoke and charred meat intake. Two coding region mEH variants located in exon 3 (Tyr113His) and exon 4 (His139Arg) have been described and may affect the enzyme's specific activity. We investigated these polymorphisms and tested interactions with smoking and charred meat intake in relation to risk of colorectal adenoma in two case-control studies nested in the Nurses' Health Study (NHS) and Health Professionals Follow-up Study (HPFS) cohorts. mEH exon 3 and exon 4 polymorphisms were not associated with overall risk of adenoma among 556 incident cases and 557 controls from the NHS or 376 prevalent cases and 725 controls from the HPFS. A statistically significant interaction was found between the exon 4 polymorphism and smoking for men (P = 0.03) and a borderline significant interaction was found between the exon 3 polymorphism and smoking for women (P = 0.06). Women having the exon 3 'rapid' Tyr/Tyr genotype were at increased risk when exposed to either > or =25 pack-years smoking [relative risk (RR) = 2.43, 95% confidence interval (CI) 1.47-4.01] or <25 pack-years of smoking (RR = 1.73, 95% CI 1.10-2.73) relative to non-smokers. Men with the exon 4 'slow' His/His genotype were at increased risk when exposed to > or =25 pack-years smoking (RR = 2.21, 95% CI 1.43, 3.41) or <25 pack-years smoking (RR = 1.71, 95% CI 1.13-2.59) relative to non-smokers. Charred meat intake was not associated with adenoma risk and there was no significant interaction with either mEH polymorphism. Our results indicate that individuals exposed to > or =25 pack-years smoking were at increased risk for colorectal adenoma and that risk is related to dose of tobacco carcinogens and mEH activity level, but the results were not consistent between men and women.