We used factorial design to ascertain the influence of dietary fat source (linseed, sunflower and oxidized sunflower oils, and beef tallow) and the dietary supplementation with alpha-tocopheryl acetate (alpha-TA) (225 mg/kg of feed) and ascorbic acid (AA) (110 mg/kg) on dark chicken meat oxidation (lipid hydroperoxide and TBA values and cholesterol oxidation product content). alpha-TA greatly protected ground and vacuum-packaged raw or cooked meat from fatty acid and cholesterol oxidation after 0, 3.5, or 7 mo of storage at -20 C. In contrast, AA provided no protection, and no synergism between alpha-TA and AA was observed. Polyunsaturated fatty acid-enriched diets (those containing linseed, sunflower, or oxidized sunflower oils) increased meat susceptibility to oxidation. Cooking always involved more oxidation, especially in samples from linseed oil diets. The values of all the oxidative parameters showed a highly significant negative correlation with the alpha-tocopherol content of meat.

The cardiovascular actions of a commercial chicken-meat extract known as Brand's Essence of Chicken (Cerebos Pacific Ltd, Singapore; BEC) were investigated in normo- and hypertensive rats. The spontaneously-hypertensive rat (SHR), Wistar Kyoto rat (WKY) and Sprague Dawley rat (SD) were used. The effect of oral feeding of BEC on hypertension, cardiac hypertrophy and arteriosclerosis in these animals was studied. The data showed the following effects of oral feeding of BEC: (1) feeding for 30 d did not affect the blood pressure and heart rate (determined telemetrically) of adult SHR and WKY; (2) feeding for 90 d did not affect the development of hypertension in 1-month-old prehypertensive SHR; (3) feeding for 4 d dose-dependently (0.2--3.2 ml/kg per d) attenuated cardiac hypertrophy in experimentally-induced (coarctation of the abdominal aorta) cardiac hypertrophic SD; (4) feeding to 1-month-old prehypertensive SHR for 11 months did not affect the age-related development of hypertension in this animal; (5) there was significant attenuation of the age-related development of hypertension (determined by tail-cuff plethysmography) in the WKY (P = 0.011) when the animals drank an average of 7.5 ml BEC/kg body weight per d, measured during the last 2 months of the 11-month treatment period; (6) there was chronic, as in the previous treatment, attenuation of the age-related development of cardiac hypertrophy and arteriosclerosis (quantified morphometrically) in the SHR when the animals drank an average of 2.4 ml BEC/kg per d, measured during the last 2 months of the 11-month treatment period. A parallel study using laboratory-prepared chicken-meat and pork extracts showed that the former, but not the latter, attenuated cardiac hypertrophy in experimentally-induced cardiac hypertrophic SD. These findings, showing that chicken-meat extract (both BEC and laboratory prepared) could have anti-cardiac hypertrophic, anti-hypertensive and anti-arteriosclerotic actions, were unexpected and provoking, and would challenge nutritional scientists with an interest in meat consumption and cardiovascular diseases.

High intake of red meat or processed meat is associated with increased risk of colon cancer. In contrast, consumption of white meat (chicken) is not associated with risk and might even reduce the occurrence of colorectal cancer. We speculated that a diet containing beef or bacon would increase and a diet containing chicken would decrease colon carcinogenesis in rats. One hundred female Fischer 344 rats were given a single injection of azoxymethane (20 mg/kg i.p.), then randomized to 10 different AIN-76-based diets. Five diets were adjusted to 14% fat and 23% protein and five other diets to 28% fat and 40% protein. Fat and protein were supplied by 1) lard and casein, 2) olive oil and casein, 3) beef, 4) chicken with skin, and 5) bacon. Meat diets contained 30% or 60% freeze-dried fried meat. The diets were given ad libitum for 100 days, then colon tumor promotion was assessed by the multiplicity of aberrant crypt foci [number of crypts per aberrant crypt focus (ACF)]. The ACF multiplicity was nearly the same in all groups, except bacon-fed rats, with no effect of fat and protein level or source (p = 0.7 between 8 groups by analysis of variance). In contrast, compared with lard- and casein-fed controls, the ACF multiplicity was reduced by 12% in rats fed a diet with 30% bacon and by 20% in rats fed a diet with 60% bacon (p < 0.001). The water intake was higher in bacon-fed rats than in controls (p < 0.0001). The concentrations of iron and bile acids in fecal water and total fatty acids in feces changed with diet, but there was no correlation between these concentrations and the ACF multiplicity. Thus the hypothesis that colonic iron, bile acids, or total fatty acids can promote colon tumors is not supported by this study. The results suggest that, in rats, beef does not promote the growth of ACF and chicken does not protect against colon carcinogenesis. A bacon-based diet appears to protect against carcinogenesis, perhaps because bacon contains 5% NaCl and increased the rats' water intake.

High cholesterol saturated lipids ingestion has been linked to the increment of coronary diseases, particularly atherosclerosis. In this study, samples of viscera and chicken meat, as well as manufactured chicken products are characterized from the point of view of their sterol content, specially cholesterol, with the purpose to determine their nutritional quality and to contribute with the development of Venezuelan food composition tables. Gas-liquid chromatography was the method chosen for the separation and quantification of cholesterol and fitosterols eventually present. The method involves lipids extraction, direct saponification, extraction of the unsaponifiable matter and its injection in the gas chromatograph. The average cholesterol values in mg/100 g. wet sample were: 31.13 (manufactured chicken breast); 57,35 (ham like type of product made with chicken); 69.02 (chicken sausages); 60.46 (chicken "bologna").

Chicken meat labeled in vivo with radio-B12 was ingested by normal volunteers. The absorption, measured by the fecal excretion method, was similar to that reported for crystalline radiocyanocobalamin and for mutton, but exceeded that from eggs. Parenteral injection of 1000 microgram of nonlabeled vitamin B12 did not interfere with the absorption of the radio-B12 from the meat. The urinary radioactivities, which were as low as those after oral administration of radioactive hydroxocobalamin and vitamin B12 coenzyme, suggested that the radio-B12 was present in meat in coenzyme form or was converted into the stable hydroxoform during the process of cooking and digestion. Patients with pernicious anemia showed insignificant urinary radioactivities in a standardized urinary excretion test using chicken meat whereas subjects with simple gastric achlorhydria and partial gastrectomy had subnormal values although their absorption of crystalline radiocyanocobalamin was normal. The subnormal serum vitamin B12 concentration seen in these latter subjects may, therefore, be due to impaired assimilation of vitamin B12 from food.

The contents of cholesterol oxides, cholesterol, and total lipid, and the fatty acid composition were determined in frozen turkey meat. The 7-ketocholesterol content varied from 33 microg/100 g in the breast to 765 microg/100 g in the skin, and the levels of 7 beta-hydroxycholesterol varied from not detected in the leg, breast, and skin to 370 microg/100 g in the skin. The values for total lipid (g/100 g) in the wings, legs, breast, and skin were 0.9 +/- 0.4, 1.1 +/- 0.2, 0.5 +/- 0.1, and 12 +/- 3, respectively. The contents for cholesterol (mg/100 g) were 46 +/- 5, 35 +/- 2, 27 +/- 3, and 81 +/- 6 in the wing, legs, breast, and skin, respectively. The main fatty acids identified in all cuts were C18:2n6, C18:1n9, C16:0, C18:0, and C20:4n6.

Br Poult Sci. 1987 Mar;28(1):3-13
Gordon memorial lecture. Poultry disease and public health.
Kampelmacher EH.

The development of the poultry industry and the consumption of poultry meat is traced over the past quarter of a century and related to the increased incidence of food poisoning in man. Factors affecting the spread of the main poultry pathogens which are of human significance are discussed. The pathogens considered are salmonella, campylobacter, staphylococci and clostridia. Various preventative measures are considered including rearing procedures for poultry, decontamination methods and education of the public. It is concluded that one of the most effective measures is irradiation of poultry and poultry products. The difficulties of introducing this control measure are recognised. It is concluded that more effective application of existing control methods would greatly reduce the hazards to public health.

Using cross-sectional data from the longitudinal Coronary Artery Risk Development in Young Adults (CARDIA) study, we assessed associations between meat consumption and other dietary- and health-status indicators. Less than one percent of this sample (n = 32) ate no red meat or poultry, and another 1% (n = 47) ate red meat or poultry less than once per week. Individuals who ate red meat and poultry less than once per week were less likely to drink alcohol (P = 0.003); reported more physical activity (P less than or equal to 0.001); had lower [corrected] Keys scores (P less than or equal to 0.001); consumed diets higher in carbohydrates, starch, fiber, vitamins A and C, and calcium and lower in energy, fat, and protein (P less than or equal to 0.001); had smaller body sizes as indicated by the body mass index [calculated as wt(kg)/ht(m2)] (P = 0.01); and had lower concentrations of total serum cholesterol (P = 0.001), low-density-lipoprotein cholesterol (P = 0.001), and triglycerides (P = 0.015) compared with individuals who consumed meat more frequently.

Some evidence suggests that diets high in animal fat or red meat may increase the risk of colon cancer, whereas high intake of fiber or vegetables may be protective. Frequently, intake of red meat has been a stronger risk factor than total fat. Because data from prospective cohort studies are sparse, we examined fat, meat, fiber, and vegetable intake in relation to risk of colon cancer in a cohort of 47,949 U.S. male health professionals who were free of diagnosed cancer in 1986. At baseline, these men, 40 to 75 years of age, completed a validated food frequency questionnaire and provided detailed information on other lifestyle and health-related factors. Between 1986 and 1992, 205 new cases of colon cancer were diagnosed in these men. Intakes of total fat, saturated fat, and animal fat were not related to risk of colon cancer. However, an elevated risk of colon cancer was associated with red meat intake (relative risk, 1.71; 95% confidence interval, 1.15-2.55 between high and low quintiles; P = 0.005 for trend). Men who ate beef, pork, or lamb as a main dish five or more times per week had a relative risk of 3.57 (95% confidence interval, 1.58-8.06; P = 0.01 for trend) compared to men eating these foods less than once per month. The association with red meat was not confounded appreciably by other dietary factors, physical activity, body mass, alcohol intake, cigarette smoking, or aspirin use. Other sources of animal fat, including dairy products, poultry, and fish as well as vegetable fat, were slightly inversely related to risk of colon cancer. No clear association existed between fiber or vegetable intake and risk of colon cancer. These data support the hypothesis that intake of red meat is related to an elevated risk of colon cancer.

OBJECTIVE: To document the contribution of meat consumption to the overall nutritional quality of the diet and assess its impact on cardiovascular risk factors in young adults. DESIGN AND SETTING: A cross-sectional survey of young adults in Bogalusa, La. SUBJECTS: We collected 24-hour dietary recalls from 504 19- to 28-year-olds from 1988 through 1991. STATISTICAL ANALYSES: We examined dietary composition by meat consumption quartiles. Analysis of variance and Newman-Keuls range tests were performed. RESULTS: Young adults consume an average of 6.5 oz meat daily; whites most often consumed beef and blacks most often consumed pork and poultry. Persons in the < 25th percentile for meat consumption consumed a diet closest to recommended levels--with 11% of energy from protein, 55% from carbohydrate, 32% from fat, 11% from saturated fatty acids, and 264 mg dietary cholesterol. In contrast, persons in the > 75th percentile for meat consumption consumed a diet with 18% of energy from protein, 40% from carbohydrate, 41% from fat, 13% from saturated fatty acids, and 372 mg dietary cholesterol. Intakes of heme iron and phosphorus were lower and calcium intake higher in persons in the < 25th percentile compared with those in the > 75th percentile for meat consumption. The percent of persons meeting two thirds of the Recommended Dietary Allowances for vitamin B-12, niacin, and zinc was greater in the > 75th percentile for meat consumption compared with the < 25th percentile for meat consumption. We noted no differences across meat consumption quartiles in blood lipids and lipoproteins, anthropometric measurements, and hemoglobin levels. APPLICATIONS/CONCLUSIONS: Consumption of moderate amounts of lean meat, along with healthier choices in other food groups, may be necessary to meet the current dietary recommendations.

Based on epidemiological studies it is assumed that meat, especially red meat, enhances risk for cancer, particularly of the colon, breast and prostate. Meat and meat products are important sources of protein, some micronutrients and fat. High fat intake has been blamed for correlation with different diseases, including cancer. Meat protein is reported to contribute to cancer formation. However, meat, including liver, is not only composed of fat and protein, it contains essential nutrients which appear exclusively in meat (vitamin A, vitamin B12) and micronutrients for which meat is the major source because of either high concentrations or better bioavailability (folate, selenium, zinc). In particular, vitamin A, folate and selenium are reported to be cancer-preventive, with respect to colon, breast and prostate cancer. Taken together, meat consists of a few, not clearly defined cancer-promoting and a lot of cancer-protecting factors. The latter can be optimized by a diet containing fruit and vegetables, which contain hundreds of more or less proven bioactive constituents, many of them showing antioxidative and anticarcinogenic effects in vitro.

Up to 80% of breast, bowel and prostate cancers are attributed to dietary practices, and international comparisons show strong positive associations with meat consumption. Estimates of relative risk obtained from cohort investigations are in the same direction, although generally weak, and red and processed meats rather than white meat seem to be associated with elevated risk of colon cancer. In breast cancer, there are consistent associations with total meat intake and there is evidence of a dose response. Despite these associations with meat, existing studies suggest that vegetarians do not have reduced risk of breast, bowel or prostate cancer, but there are no quantitative estimates of amounts of meat consumed by meat eaters in these cohort studies. Possible mechanisms underlying epidemiological associations include the formation of heterocyclic amines in meat when it is cooked. These heterocyclic amines require acetylation by P450 enzymes, and individuals with the fast-acetylating genotype who eat high amounts of meat may be at increased risk of large-bowel cancer. NH3 and N-nitroso compounds (NOC) formed from residues by bacteria in the large bowel and probably also important. NH3 is a promotor of large-bowel tumours chemically induced by NOC, and some of the chromosomal mutations found in human colo-rectal cancer are consistent with effects of NOC and heterocyclic amines. However, the type, amount, and cooking method of meat or protein associated with increased risk are not certain. The effects of high levels of meat on NH3 and NOC output are not reduced by increasing the amount of fermentable carbohydrate in the diet, but interaction between meat, NSP and vegetable intakes on the risk of cancer has not been studied comprehensively. The interaction between dietary low-penetrance genetic polymorphic and somatic mutation factors has also been investigated to a limited extent. Current Department of Health (1998) recommendations are that meat consumption should not rise, and that consumers at the top end of the distribution should consider a reduction in intakes.

A randomised crossover dietary intervention study was performed to evaluate the effects of replacing meat protein in the diet with a soyabean product, tofu, on blood concentrations of testosterone, dihydrotestosterone, androstanediol glucuronide, oestradiol, sex hormone-binding globulin (SHBG), and the free androgen index (total testosterone concentration/SHBG concentration x 100; FAI). Forty-two healthy adult males aged 35-62 years were studied. Diets were isoenergetic, with either 150 g lean meat or 290 g tofu daily providing an equivalent amount of macronutrients, with only the source of protein differing between the two diets. Each diet lasted for 4 weeks, with a 2-week interval between interventions. Fasting blood samples were taken between 07.00 and 09.30 hours. Urinary excretion of genistein and daidzein was significantly higher after the tofu diet (P < 0.001). Blood concentrations of sex hormones did not differ after the two diets, but the mean testosterone:oestradiol value was 10% higher (P = 0.06) after the meat diet. SHBG was 3% higher (P = 0.07), whereas the FAI was 7% lower (P = 0.06), after the tofu diet compared with the meat diet. There was a significant correlation between the difference in SHBG and testosterone:oestradiol and weight change. Adjusting for weight change revealed SHBG to be 8.8% higher on the tofu diet (mean difference 3 (95% CI 0.7, 5.2) nmol/l; P = 0.01) and testosterone:oestradiol to be significantly lower, P = 0.049). Thus, replacement of meat protein with soyabean protein, as tofu, may have a minor effect on biologically-active sex hormones, which could influence prostate cancer risk. However, other factors or mechanisms may also be responsible for the different incidence rates in men on different diets.

Canadians are becoming increasingly aware of the importance of nutrition in their long-term health prospects. With this increased awareness, however, has come an abundance of misconceptions including the notion that meat is "bad" for you. In their haste to avoid saturated fat, physicians and the public alike have lost sight of the fact that lean meat in reasonable serving sizes poses no threat to health and is an extremely important source of many nutrients. The mistaken notion that only animal fats are saturated has resulted in a change in the source of fat but not the quantity. Health professionals must work together to educate the public about the many nutrient-dense, low-fat food choices available in a well-balanced diet.

From the point of view of the nutritionist, meat has an important role to play in supplying the body with proteins (essential amino acids, vitamins and minerals). There is no doubt that meat is the most valuable source of dietary iron. These facts make meat an important constituent of a balanced diet in a range of age and performance groups, including children and adolescents, pregnant women and nursing mothers, senior citizens and athletes. In the discussion about the nutritional/physiological quality of meat and meat products, total fat, cholesterol and purines must also be considered. About 80 g of lean meat per day, or a portion of about 150 g three times a week in patients with disorders of fat metabolism or elevated uric acid levels complies with the recommendations for low-fat and low-cholesterol alimentation, and helps ensure a balanced diet.

Scientific evidence is accumulating that meat itself is not a risk factor for Western lifestyle diseases such as cardiovascular disease, but rather the risk stems from the excessive fat and particularly saturated fat associated with the meat of modern domesticated animals. In our own studies, we have shown evidence that diets high in lean red meat can actually lower plasma cholesterol, contribute significantly to tissue omega-3 fatty acid and provide a good source of iron, zinc and vitamin B12. A study of human and pre-human diet history shows that for a period of at least 2 million years the human ancestral line had been consuming increasing quantities of meat. During that time, evolutionary selection was in action, adapting our genetic make up and hence our physiological features to a diet high in lean meat. This meat was wild game meat, low in total and saturated fat and relatively rich in polyunsaturated fatty acids (PUFA). The evidence presented in this review looks at various lines of study which indicate the reliance on meat intake as a major energy source by pre-agricultural humans. The distinct fields briefly reviewed include: fossil isotope studies, human gut morphology, human encephalisation and energy requirements, optimal foraging theory, insulin resistance and studies on hunter-gatherer societies. In conclusion, lean meat is a healthy and beneficial component of any well-balanced diet as long as it is fat trimmed and consumed as part of a varied diet.

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.

BACKGROUND: More than 20 studies have investigated the relation between meat and dairy food consumption and breast cancer risk with conflicting results. Our objective was to evaluate the risk of breast cancer associated with meat and dairy food consumption and to assess whether non-dietary risk factors modify the relation. METHODS: We combined the primary data from eight prospective cohort studies from North America and Western Europe with at least 200 incident breast cancer cases, assessment of usual food and nutrient intakes, and a validation study of the dietary assessment instrument. The pooled database included 351,041 women, 7379 of whom were diagnosed with invasive breast cancer during up to 15 years of follow-up. RESULTS: We found no significant association between intakes of total meat, red meat, white meat, total dairy fluids, or total dairy solids and breast cancer risk. Categorical analyses suggested a J-shaped association for egg consumption where, compared to women who did not eat eggs, breast cancer risk was slightly decreased among women who consumed < 2 eggs per week but slightly increased among women who consumed > or = 1 egg per day. CONCLUSIONS: We found no significant associations between intake of meat or dairy products and risk of breast cancer. An inconsistent relation between egg consumption and risk of breast cancer merits further investigation.

Interviews undertaken in a study of consumers' views on food quality were re-analysed with special reference to the narrative themes raised by consumers when describing their views on the quality of meat and meat products. Negative attitudes towards meat were frequently expressed, and with more emotion than comments about any other food. Being based on interviews made prior to the BSE crisis, the study gives evidence that the popularity of meat was in a process of decline already before this crisis. It was found that critical attitudes centred around the following four themes: the manner in which meat is produced and processed in modern agriculture and industry, the fact that meat derives from animals, the food culture associated with meat eating and the perceived unhealthiness of meat. In spite of their critical attitudes, the interviewees nevertheless consumed meat on a daily basis. This study suggests that negative attitudes towards meat are not necessarily associated with decreased meat consumption, but are associated with a tendency to re-structure meals with special reference to the role assigned to meat.