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PubMed2004

Effect of electron beam irradiation and storage at 5 degrees C on thiobarbituric acid reactive substances and carbonyl contents in chicken breast meat infused with antioxidants and selected plant extracts.

This study evaluated the effectiveness of synthetic and natural antioxidants, green tea, commercial grape seed extracts/combinations, and TBHQ, with varying concentrations of lipid oxidation of nonirradiated and irradiated chicken breast meats stored at 5 degrees C for 12 days. Fresh boneless and skinless chicken breast meats were vacuum-infused with varying concentrations of antioxidants: green tea, grape seed extracts alone/in combination, and TBHQ. The irradiation dosage was 3.0 kGy. Carbonyl values of raw chicken meat and thiobarbituric acid reactive substances (TBARS) values of raw and cooked chicken meat were determined for 0-12 days at 5 degrees C storage. TBARS values for 0-12 days of storage at 5 degrees C ranged from 1.21 to 7.3 and 1.22 to 8.51 mg malondialdehyde/100 g chicken for nonirradiated and irradiated raw chicken, respectively. TBARS values of cooked chicken ranged from 2.19 to 35.83 and 2.45 to 45.72 mg malondialdehyde/100 g chicken for nonirradiated and irradiated chicken, respectively. Irradiation increased TBARS values of both controls and plant extracts. The carbonyl content in meat lipid ranged from 1.7 to 2.9 and 1.7 to 4.41 micromol acetophenone/10 g of nonirradiated and irradiated chicken meat, respectively, and meat protein ranged from 1.4 to 2.07 and 1.41 to 2.72 micromol/10 g meat. Infusion of chicken meat with selected plant extracts is an effective method to minimize lipid oxidation and volatiles developments caused by irradiation.

Acetophenones↗
PubMed2000

Investigation on the possible formation of N-nitroso-N-methylurea by nitrosation of creatinine in model systems and in cured meats at gastric pH.

N-Nitroso-N-methylurea (NMU) is a highly potent direct-acting carcinogen that has been shown to induce cancer in a number of animal species. Although previous research has indicated that nitrosation of creatinine (CRN), a common constituent of meats, dried fish, and seafoods, can form traces of NMU, there is uncertainty as to (1) the yield of NMU and (2) whether detectable amounts of NMU can be formed from cured meats following nitrosation under acidic conditions given the low residual levels of nitrite found in cured meats at the present time. Lack of sensitive and specific analytical methods most likely has hindered progress in research in these areas. An HPLC postcolumn denitrosation-thermal energy analyzer technique and a GC-MS confirmation technique were developed for the determination of NMU in cured meats. Both techniques are highly sensitive (0.5 and 0.03 ppb, respectively) and specific. The optimum pH for NMU formation from CRN ranged between pH 1 and pH 3, and the yields of NMU under variable reactant concentrations ranged between 0.00004 and 0.0046%. When 27 samples of various cured meats (10 g aliquots each) were acidified with HCl (final pH values of 0.8-2.5) and incubated at room temperature for 2 h, without any additional nitrite, 24 gave results below detectable levels but 3 formed 2-26 ng of NMU/10 g of meat. Incubation of the negative meats with additional nitrite (50-500 microg/g of meat) formed 0.6-176 ng of NMU/10 g of sample. Although the amounts of NMU formed were extremely small, this seems to be the first reported formation of NMU from cured meats with and without additional nitrite.

Creatinine↗
PubMed1999

The association of diet and thrombotic risk factors in healthy male vegetarians and meat-eaters.

OBJECTIVE: The aim of this study was to assess thrombosis tendency in subjects who were habitual meat-eaters compared with those who were habitual vegetarians. DESIGN: Cross-sectional comparison of habitual meat-eaters and habitual vegetarians. SETTING: Free living subjects. SUBJECTS: One hundred and thirty-nine healthy male subjects (vegans n = 18, ovolacto vegetarians n = 43, moderate-meat-eaters n = 60 and high-meat-eaters n = 18) aged 20-55 y who were recruited in Melbourne. OUTCOME MEASURES: Dietary intake was assessed using a semi-quantitative Food Frequency Questionnaire. The parameters of thrombosis were measured by standard methods. RESULTS: Saturated fat and cholesterol intakes were significantly higher and polyunsaturated fat (PUFA) was significantly lower in the meat-eaters compared with vegetarians. In the meat-eaters, the platelet phospholipids AA levels were significantly higher than in the vegetarians, but there was no increase in ex vivo platelet aggregation and plasma 11-dehydro thromboxane B2 levels. Vegetarians, especially the vegans, had a significantly increased mean collagen and ADP stimulated ex vivo whole blood platelet aggregation compared with meat-eaters. The vegan group had a significantly higher mean platelet volume than the other three dietary groups. However, meat-eaters had a significantly higher cluster of cardiovascular risk factors compared with vegetarians, including increased body mass index, waist to hip ratio, plasma total cholesterol (TC), triacylglycerol and LDL-C levels, ratio of TC/HDL-C and LDL-C/HDL-C and plasma factor VII activity. CONCLUSIONS: Consumption of meat is not associated with an increased platelet aggregation compared with vegetarian subjects.

Adult↗
PubMed2001

The influence of fish, meat and polyunsaturated fat intakes on platelet phospholipid polyunsaturated fatty acids in male Melbourne Chinese and Caucasian.

OBJECTIVE: The aims of this study were to investigate (1) platelet phospholipid (PL) polyunsaturated fatty acid (PUFA) composition in subjects who were the Melbourne Chinese migrants, compared with those who were the Melbourne Caucasians and (2) the relationship between platelet PL PUFA and intake of fish, meat and PUFA. DESIGN: Cross-sectional comparison of the Melbourne Chinese and Caucasians. SETTING: Free-living male subjects. SUBJECTS: Ninety-seven Melbourne Chinese migrants and 78 Melbourne Caucasians who were recruited in Melbourne. OUTCOME MEASURES: Dietary intake was assessed using a semi-quantitative food frequency questionnaire. The platelet PUFA was measured by gas-liquid chromatography. RESULTS: The Melbourne Chinese had significantly higher proportions of platelet PL 20:5n-3 (P=0.006), 22:6n-3 (P<0.0001), total n-3 (P=0.027) and 22:5n-6 (P=0.0002), and a significantly higher intake of fish (P=0.012) and white meat (P=0.0045) compared with the Melbourne Caucasians. In addition, the Melbourne Chinese had significantly lower proportions of 20:3n-6 (P=0.023), 20:4n-6 (P<0.002), 22:4n-6 (P<0.0001), total n-6 (P=0.037), 22:5n-3 (P<0.0001) and ratio of n-6/n-3 (P=0.011), and a significantly lower intake of red and total meat (P<0.0001) than the Melbourne Caucasians. Fish consumption was significantly positively correlated with platelet PL 20:5n-3 and 22:6n-3, and significantly negatively correlated with 22:5n-3 (P<0.05). Meat consumption was significantly positively correlated with 22:5n-3 and significantly negatively correlated with 22:5n-6, 20:5n-3 and 22:6n-3 (P<0.05). Dietary PUFA intake was significantly positively correlated with 20:3n-6, 22:4n-6 and 22:5n-3, and significantly negatively correlated with 22:5n-6, 20:5n-3 and 22:6n-3 (P<0.05). CONCLUSIONS: Compared with Caucasians, the Melbourne Chinese had a significantly higher level of platelet PL n-3 PUFA, which might contribute to the low CVD mortality in this population. Platelet PL 20:5n-3 and 22:6n-3 were significantly positively correlated with fish intake, and negatively significantly correlated with dietary intake of meat and PUFA, while 22:5n-3 was significantly positively correlated with dietary meat and PUFA intake, and significantly negatively correlated with fish intake. Dietary intake of PUFA and fish are potential confounding factors for assessing the effects of meat consumption on platelet PL individual PUFA. Dietary intake of PUFA and meat did not influence the incorporation of fish long chain n-3 PUFA to platelet PL in this study population. SPONSORSHIP: Palm Oil Research Institute of Malaysia, Meat Research Corporation Australia.

Adult↗
PubMed1990

Review of current techniques for the verification of the species origin of meat.

An overview of developments that have occurred in meat species identification over the last decade is presented. It starts by noting the different requirements for speciation techniques over the period, describes the complex nature of meat in terms of chemical composition and shows how the chain of events from slaughter to retail gives rise to opportunities for deliberate adulteration or innocent contamination. The limitations of techniques such as electrophoresis and isoelectrofocusing are pointed out where the analysis of mixed meats is concerned; attention then focuses on the range of techniques based on antigen-antibody interactions: agar gel immunodiffusion, counter immuno-electrophoresis and enzyme-linked immunosorbent assay (ELISA) in three formats. The choice of analyte is discussed, firstly for the analyses of raw meat materials and secondly, for heat-processed meat products. In the first example, blood serum proteins are used almost exclusively despite the limitation that their presence does not necessarily denote the presence of the corresponding muscle tissue (meat). For cooked products, a new range of antisera are necessary, based on thermally stable components derived from the tissues. By using different formats of ELISA, it is demonstrated that different responses can be obtained for heat-processed meat versus processed offal, and that determination of a species meat content in a cooked mixed meat product is possible. Techniques for improving the specificity and performance of antisera are discussed briefly, with the future introduction of thermally stable, muscle-specific monoclonal antisera being seen as the way forward.

Animals↗
PubMed1983

Availability of iron from chicken meat and liver given to rats.

The concentration and distribution of iron in 59Fe-labelled chicken leg and breast meat and liver were determined by gel filtration. In all samples approximately 50% of the Fe was insoluble (haemosiderin) and the haemoproteins (haemoglobin and myoglobin) constituted from 15% (liver) to 25% (leg meat) of the total Fe. Ferritin accounted for from 12% (leg meat) to 27% (liver) of the total Fe. A technique was developed which enabled the time-course of the passage of 59Fe-labelled whole and fractionated meat and liver through the gastrointestinal tract of Fe-replete and Fe-deficient rats to be followed and it was found that the rate of stomach emptying appeared to be a function of the viscosity of the meal. In Fe-replete rats approximately 71% of a meal of raw chicken meat had left the stomach within 1 h of administration and by 2 h the stomach was almost empty and much of the unabsorbed 59Fe was in the ileum. By 4 h the ileum and colon contained almost equal amounts of 59Fe. Between different test meals there were only slight differences in gastrointestinal distribution and these reflected the different rates of stomach emptying. Stomach emptying was slower in Fe-deficient compared with Fe-replete rats. In Fe-replete, but not Fe-deficient, rats it was found that the amount of 59Fe lost (absorbed) from the gastrointestinal tract 2 h after administration of a test meal was not significantly different from the value found using a 7 d faecal collection technique. Comparison of the 2 h absorption values for several test meals indicated that 59Fe absorption from raw whole meat was significantly higher than from the soluble extract and the residue after extraction (haemosiderin). Heat treatment caused a significant decrease in the absorption of Fe in whole meat and the soluble meat extract but a significant increase in the liver absorption values. It is suggested that denatured haemoproteins are less available for absorption than their native forms but that heating increases the availability of the Fe of haemosiderin or ferritin or both. Isolated muscle ferritin was poorly absorbed but on the addition of excess bovine serum albumin the absorption of the Fe was markedly increased. It is concluded that, to estimate the Fe availability of a food such as chicken meat or liver one must not only take account of the concentration and type of each Fe-containing compound present but also such factors as their possible synergistic effects, the presence of chelating agents, the extent of cooking and the concentration and type of proteinaceous digestion products.

Animals↗
PubMed2005

Meat consumption reduces the risk of nutritional rickets and osteomalacia.

Endogenous vitamin D deficiency (low serum 25(OH)D3) is a necessary but insufficient requirement for the genesis of vitamin D-deficiency rickets and osteomalacia. The magnitude of the independent contributions of dietary factors to rachitic and osteomalacic risk remains uncertain. We reanalysed two weighed dietary surveys of sixty-two cases of rickets and osteomalacia and 113 normal women and children. The independent associations of four dietary variables (vitamin D, Ca, fibre and meat intakes) and daylight outdoor exposure with rachitic and osteomalacic relative risk were estimated by multivariate logistic regression. Meat and fibre intakes showed significant negative and positive associations respectively with rachitic and osteomalacic relative risk (RR; zero meat intake: RR 29.8 (95 % CI 4.96, 181), P<0.001; fibre intake: RR 1.53 (95 % CI 1.01, 2.32), P=0.043). The negative association of meat intakes with rachitic and osteomalacic relative risk was curvilinear; relative risk did not fall further at meat intakes above 60 g daily. Daylight outdoor exposure showed a significant negative association with combined relative risk (RR 0.33 (95 % CI 0.17, 0.66), P<0.001). Operation of the meat and fibre risk factors was related to sex, age and dietary pattern (omnivore/lactovegetarian), mainly determined by religious affiliation. The mechanism by which meat reduces rachitic and osteomalacic risk is uncertain and appears independent of revised estimates of meat vitamin D content. The meat content of the omnivore Western diet may explain its high degree of protection against nutritional rickets and osteomalacia from infancy to old age in the presence of endogenous vitamin D deficiency.

Adolescent↗
PubMed1998

Effect of dietary administration of oil extracts from rosemary and sage on lipid oxidation in broiler meat.

1. Oxidation of meat and membrane from broilers fed on a diet containing 500 mg/kg rosemary and sage extracts was compared to meat and membrane oxidation from broilers receiving a control diet (not enriched with antioxidants) and a diet enriched in alpha-tocopheryl acetate (200 mg/kg). 2. After 9 d of refrigerated storage, thiobarbituric acid reactive substances of white meat from broilers fed on the control and the alpha-tocopheryl acetate-enriched diets were 0.51 and 0.25 mg malonaldehyde/kg meat, respectively. Values for meat from broilers fed on the diets containing the rosemary and sage extracts were in the range 0.30 to 0.35 mg malonaldehyde/kg meat, significantly lower than those from birds fed on the control diet. A similar trend was observed in the dark meat but differences were not significant at 9 d of storage. Similar trends were observed in raw samples stored at -20 degrees C for up to 4 months and in samples cooked at 70 degrees C and kept stored under refrigeration for up to 4 d. 3. The meat from broilers fed on the diet containing spice extracts had smaller concentrations of total cholesterol oxidation products (COPS) than meat from the control group (P < 0.05). Supplemental alpha-tocopheryl acetate reduced the COPS concentrations to a greater extent than did spice extracts (P < 0.05). 4. A similar trend was observed in microsomal fraction isolates, in which the rate of metmyoglobin/hydrogen peroxide-catalysed lipid peroxidation was lower in animals receiving spice extracts than in those fed on the basal diet.

Abattoirs↗
PubMed1997

Effect of technological treatments on digestibility and allergenicity of meat-based baby foods.

OBJECTIVE: When suitability prepared according to particular characteristics of hygiene and digestibility, meat is an important food for human weaning. The present knowledge on meat digestibility and allergenicity are not enough to justify removal of meat from a child's diet when there is risk but no clinical evidence of allergy. Based on these considerations, the role of technological treatments on digestibility and allergenicity of meat-based baby foods is considered. SUBJECTS: Eight children (five males and three females) suffering from atopic dermatitis (AD), aged 3.8 to 7.1 years (mean age 4.86 +/- 1.10 years). STUDY DESIGN AND METHODS: An in vitro multienzymatic digestibility assay was used to evaluate proteolysis in meat samples (from four different animal species). The experimental design included raw, steam-cooked (home-made and industrial cooking), homogenized (strained) and freeze-dried meat samples. Skin prick test (SPT) was performed to evaluate positive responses to meat samples (raw, cooked, strained and freeze-dried) from four animal species. RESULTS: Our data indicate that enzymatic attack is strongly affected by heat treatment as shown in steam-cooked meat samples. On the other hand, blending, homogenization and freeze-drying processes are able to partially reverse the phenomenon. Data on modification of sodium dodecyl sulfate-polyacrylamide gel rlectrophoresis (SDS-PAGE) protein pattern during the multienzymatic assay are reported. Cooking and technological treatments reduce positive responses obtained in SPT. CONCLUSIONS: Technological treatments improve digestibility and reduce antigenicity of meat products.

Animals↗
PubMedDate not supplied

Health communication and consumer behavior on meat in Belgium: from BSE until dioxin.

This article focuses on the impact of mass media meat-health information on consumer perception, attitude, and behavior toward fresh meat in Belgium. In a situation similar to that which occurred in most other European countries, Belgian fresh meat consumption fell considerably during 1995-1999. A multitude of messages linking meat consumption to human health risks were reported by mass media. Bovine Spongiform Encephalopathy (BSE) since 1996 and dioxin in 1999 constituted the major issues. Empirical research, conducted in April 1998, revealed the tremendous negative impact of mass media coverage of meat-health issues on consumer risk perception, health concern, and attitude and behavior toward fresh meat. Oppositely, personal communication through butchers had only a small effect on consumer decision-making in this era dominated by alarming meat-health press. Implications are threefold. First, mass media should be aware of its social responsibilities, which include spreading reliable and correct information to the society. This is especially the case as human health risks are involved. Second, the meat industry urgently needs to reorient itself toward quality, safety, and transparency. Finally, future communication dealing with similar crises situations requires cooperation across the meat chain, government, and those who are responsible for public health promotion and communication.

Animals↗
PubMed2002

Analysis of soyabean proteins in meat products: a review.

The use of soyabean proteins as meat extenders has spread significantly due to the interesting nutritional and functional properties that are present in soyabean proteins. Together with these, health and economical reasons are the major causes for the addition of soyabean proteins to meat products. Nevertheless, despite the good properties associated to soyabean proteins, there are many countries in which the addition of these proteins is forbidden or in which the addition of soyabean proteins is allowed up to a certain extent. Thus, the need of analytical methods enabling the detection of added soyabean proteins in meat products is obvious. Microscopic, electrophoretic, immunologic, and chromatographic methods are the most widely used for this purpose. However, the detection of soyabean proteins in meat products presents difficulties related to the composition (meat species, meat quality, soyabean protein source, presence of other non-meat proteins, etc.) and the processing of the meat products, and, although these analytical methods have tried to overcome all these difficulties, there is still not a method enabling quantitative assessment of soyabean proteins in all kinds of meat products.

Humans↗
PubMed2006

Meat intake and bladder cancer risk in 2 prospective cohort studies.

BACKGROUND: Nitrosamines, which are known bladder carcinogens, or their precursors are found in certain meat items, and concentrations of these compounds are especially high in bacon. Only 3 cohort studies, all with <100 case subjects, have examined the relation between meat intake and bladder cancer, and few studies have examined the relation of different meat types with bladder cancer. OBJECTIVE: The aim was to examine the association between specific meat items and bladder cancer in 2 large prospective studies. DESIGN: We analyzed data from 2 cohorts with up to 22 y of follow-up and 808 incident bladder cancer cases. Detailed data on meat were obtained from multiple food-frequency questionnaires administered over time. Multivariate relative risks (RRs) and 95% CIs were estimated by using Cox proportional hazards models with control for potential confounders, including detailed smoking history. RESULTS: Men and women with a high intake of bacon (>/=5 servings/wk) had an elevated risk of bladder cancer compared with those who never ate bacon (multivariate RR = 1.59; 95% CI = 1.06, 2.37), although the overall association was not statistically significant (P for trend = 0.06). However, the association with bacon was stronger and became statistically significant after the removal of individuals who indicated having "greatly" changed their red meat (men) or bacon (women) intake during the 10 y before baseline (multivariate RR = 2.10; 95% CI = 1.24, 3.55; P for trend = 0.006). A positive association was also detected for intake of chicken without skin, but not for chicken with skin or for other meats, including processed meats, hot dogs, and hamburgers. CONCLUSIONS: In these 2 cohorts combined, frequent consumption of bacon was associated with an elevated risk of bladder cancer. Other studies with data on specific meat items are necessary to confirm our findings.

Adult↗
PubMed2000

Breast cancer, heterocyclic aromatic amines from meat and N-acetyltransferase 2 genotype.

Breast cancer risk has been hypothesized to increase with exposure to heterocyclic aromatic amines (HAAs) formed from cooking meat at high temperature. HAAs require enzymatic activation to bind to DNA and initiate carcinogenesis. N-acetyltransferase 2 (NAT2) enzyme activity may play a role, its rate determined by a polymorphic gene. We examined the effect of NAT2 genetic polymorphisms on breast cancer risk from exposure to meat by cooking method, doneness and estimated HAA [2-amino-1-methyl-6-phenylimidazole[4,5-b]pyridine (PhIP), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) and 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (DiMeIQx)] intake. Women were recruited with suspicious breast masses and questionnaire data were collected prior to biopsy to blind subjects and interviewers to diagnoses. For 114 cases with breast cancer and 280 controls with benign breast disease, NAT2 genotype was determined using allele-specific PCR amplification to detect slow acetylator mutations. HAAs were estimated from interview data on meat type, cooking method and doneness, combined with a quantitative HAA database. Logistic regression models controlled for known risk factors, first including all controls, then 108 with no or low risk (normal breast or no hyperplasia) and finally 149 with high risk (hyperplasia, atypical hyperplasia, complex fibroadenomas). Meat effects were examined within NAT2 strata to assess interactions. We found no association between NAT2 and breast cancer. These Californian women ate more white than red meat (control median 46 versus 8 g/day). There were no significant associations of breast cancer with red meat for any doneness. White meat was significantly protective (>67 versus <26 g/day, OR 0.46, 95% CI 0.23-0.94, P for trend = 0.02), as was chicken, including well done, pan fried and barbecued chicken. MeIQx and DiMeIQx were not associated with breast cancer. A protective effect of PhIP was confounded after controlling for well done chicken. Results were unchanged using low or high risk controls or dropping 30 in situ cases. There was no interaction between NAT2 and HAAs. These findings do not support a role for HAAs from meat or NAT2 in the etiology of breast cancer. Further research is needed to explain the white meat association.

Adult↗
PubMed2004

Meat intake, cooking-related mutagens and risk of colorectal adenoma in a sigmoidoscopy-based case-control study.

Reported habits of red meat consumption, particularly red meat that has been cooked to the degree termed 'well-done', is a positive risk factor for colorectal cancer. Under high, pyrolytic temperatures, heterocyclic amines (HCA) and benzo[a]pyrene (BP) molecules can form inside and on the surface of red meat, respectively. These compounds are precursors that are metabolically converted to compounds known to act as mutagens and carcinogens in animal models, yet their role in human colorectal carcinogenesis remains to be clarified. We investigated whether intake of these compounds is associated with risk of colorectal adenoma in the context of a polyp-screening study conducted in Southern California. Using a database of individual HCAs and BP in meats of various types and subjected to specified methods and degrees of cooking, we estimated nanogram consumption of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine, 2-amino-3,4,8-trimethylimidazo[4,5-f] quinoxaline, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline and benzo[a]pyrene (BP). We observed a 6% increased risk of large (>1 cm) adenoma per 10 ng/day consumption of BP [OR = 1.06 (95% CI, 1.00-1.12), P (trend) = 0.04]. A major source of BP is red meat exposed to a naked flame, as occurs during the barbecuing process. Consistent with this finding an incremental increase of 10 g of barbecued red meat per day was associated with a 29% increased risk of large adenoma [OR = 1.29 (95% CI, 1.02-1.63), P (trend) = 0.04]. Individuals in the top quintile of barbecued red meat intake were at increased risk of large adenoma [OR = 1.90 (95% CI, 1.04-3.45)], compared with never consuming barbecued red meat. The consumption of oven-broiled red meat was inversely related to adenoma risk compared with non-consumers [OR = 0.49 (95% CI, 0.28-0.85)]. We did not identify any association with consumption of individual HCAs and colorectal adenoma risk. These results support the hypothesis that BP contributes to colorectal carcinogenesis.

Adenoma↗
PubMed2002

Effect of white versus red meat on endogenous N-nitrosation in the human colon and further evidence of a dose response.

N-nitroso compounds are found in the colon and are formed endogenously because amines and amides are produced by bacterial decarboxylation of amino acids in the large gut. They can be N-nitrosated in the presence of a nitrosating agent. To test the hypothesis that increased nitrogenous residues from red meat would increase endogenous N-nitrosation, thus accounting for the epidemiologic association between red meat consumption and colorectal cancer, we fed increased levels of red meat and measured apparent total N-nitroso compounds (ATNCs) in fecal samples in a series of studies of volunteers maintained under controlled conditions. A result of these studies is that we have shown a consistent dose response to red meat consumption. Fiber, in the form of vegetables, bran or resistant starch, does not reduce the level of ATNCs formed, although transit time is reduced and fecal weight are increased. Here we show that the equivalent amount (420-600 g) of meat as white meat has no effect on fecal ATNCs in 12 volunteers (P = 0.338). At dosages of 0, 60, 120, 240 and 420 g of red meat/d, mean levels of ATNC output are highly correlated with dose of meat: for concentration ATNC versus dose of meat in g/d, r = 0.972, beta = 0.252 ng/g (SE 0.035); for total ATNC output versus dose of meat in g/d, r = 0.963, beta = 2.605 microg/d (SE 0.419). The effects of nonmeat protein and of heme on increased N-nitrosation and the genotoxic effects of the ATNCs produced are presently being investigated.

Adult↗
PubMed2003

Controlled high meat diets do not affect calcium retention or indices of bone status in healthy postmenopausal women.

Calcium balance is decreased by an increased intake of purified proteins, although the effects of common dietary sources of protein (like meat) on calcium economy remain controversial. We compared the effects of several weeks of controlled high and low meat diets on body calcium retention, using sensitive radiotracer and whole body scintillation counting methodology. Healthy postmenopausal women (n = 15) consumed diets with similar calcium content (approximately 600 mg), but either low or high in meat (12 vs. 20% of energy as protein) for 8 wk each, in a randomized crossover design. After 4 wk of equilibration of each diet, calcium retention was measured by extrinsically labeling the 2-d menu with (47)Ca, followed by whole body scintillation counting for 28 d. Urinary and blood indicators of bone metabolism were also determined for each diet. Calcium retention was not different during the high and low meat dietary periods (d 28, mean +/- pooled SD: 17.1 and 15.6%, +/-0.6%, respectively; P = 0.09). An initially higher renal acid excretion in subjects consuming the high meat compared with the low meat diet decreased significantly with time. The diets did not affect urinary calcium loss or indicators of bone metabolism. In conclusion, under controlled conditions, a high meat compared with a low meat diet for 8 wk did not affect calcium retention or biomarkers of bone metabolism in healthy postmenopausal women. Calcium retention is not reduced when subjects consume a high protein diet from common dietary sources such as meat.

Aged↗
PubMed2004

Meat consumption patterns and preparation, genetic variants of metabolic enzymes, and their association with rectal cancer in men and women.

Meat consumption, particularly of red and processed meat, is one of the most thoroughly studied dietary factors in relation to colon cancer. However, it is not clear whether meat, red meat, heterocyclic amines (HCA), or polycyclic aromatic hydrocarbons (PAH) are associated with the risk for rectal cancer. Rectal cancer cases (n = 952) and controls (n = 1205) from Utah and Northern California were recruited from a population-based case-control study between September 1997 and February 2002. Detailed in-person interviews regarding lifestyle, medical history, and diet were conducted. DNA was extracted from peripheral lymphocytes obtained from whole-blood samples, and glutathione S-transferase (GST)M1 enzyme and N-acetyl transferase (NAT)2 enzyme genotypes were assessed. Although energy and cholesterol intakes were higher among cases than controls, adjustment for confounders accounted for the differences. Increased consumption of well-done red meat [odds ratio (OR) 1.33 95% CI 0.98, 1.79] was associated with an (P = 0.04) increase in risk for rectal cancer among men. The mutagen index, calculated on the bases of reported amount, doneness, and method of cooking meat, was also positively but not significantly (P = 0.24) associated with risk of rectal cancer for men (OR 1.37 95% CI 0.98, 1.92). NAT2-imputed phenotype and GSTM1 did not consistently modify rectal cancer risk associated with meat intake. These data suggest that mutagens such as HCA that form when meat is cooked may be culpable substances in rectal cancer risk, not red meat itself.

Adult↗
PubMed2005

Meat and fat intake as risk factors for pancreatic cancer: the multiethnic cohort study.

BACKGROUND: Meat intake has been associated with risk of exocrine pancreatic cancer, but previous findings have been inconsistent. This association has been attributed to both the fat and cholesterol content of meats and to food preparation methods. We analyzed data from the prospective Multiethnic Cohort Study to investigate associations between intake of meat, other animal products, fat, and cholesterol and pancreatic cancer risk. METHODS: During 7 years of follow-up, 482 incident pancreatic cancers occurred in 190,545 cohort members. Dietary intake was assessed using a quantitative food frequency questionnaire. Associations for foods and nutrients relative to total energy intake were determined by Cox proportional hazards models stratified by gender and time on study and adjusted for age, smoking status, history of diabetes mellitus and familial pancreatic cancer, ethnicity, and energy intake. Statistical tests were two-sided. RESULTS: The strongest association was with processed meat; those in the fifth quintile of daily intake (g/1000 kcal) had a 68% increased risk compared with those in the lowest quintile (relative risk = 1.68, 95% confidence interval = 1.35 to 2.07; Ptrend < .01). The age-adjusted yearly incidence rates per 100,000 persons for the respective quintiles were 41.3 and 20.2. Intakes of pork and of total red meat were both associated with 50% increases in risk, comparing the highest with the lowest quintiles (both Ptrend < .01). There were no associations of pancreatic cancer risk with intake of poultry, fish, dairy products, eggs, total fat, saturated fat, or cholesterol. Intake of total and saturated fat from meat was associated with statistically significant increases in pancreatic cancer risk but that from dairy products was not. CONCLUSION: Red and processed meat intakes were associated with an increased risk of pancreatic cancer. Fat and saturated fat are not likely to contribute to the underlying carcinogenic mechanism because the findings for fat from meat and dairy products differed. Carcinogenic substances related to meat preparation methods might be responsible for the positive association.

Adult↗