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Objective: Association between animal products and prostate cancer have been observed in numerous observational studies, but it is not clear whether the high fat content of these foods or some other component accounts for these associations. We examine these associations among 51,529 men who contributed detailed dietary data., Methods: Participants of the Health Professionals Follow-Up Study completed a semiquantitative food-frequency questionnaire in 1986, and subsequently in 1990 and 1994. Other data on potential risk factors were collected at baseline and in subsequent questionnaires during follow-up. Between 1986 and 1996, 1897 total cases of prostate cancer (excluding stage A1) and 249 metastatic cancers were identified. We used pooled logistic regression for analyses of diet and prostate cancer., Results: Intakes of total meat, red meat, and dairy products were not associated with risk of total or advanced prostate cancer. An elevated risk for metastatic prostate cancer was observed with intake of red meat (relative risk (RR)= 1.6 for top vs. bottom quintile comparison, 95% confidence interval (CI) = 1.0-2.5); this association was slightly attenuated after controlling for saturated and alpha-linolenic fatty acids (RR = 1.5, 95% CI = 0.88-2.5). Processed meats, bacon and beef, pork or lamb as a main dish each contributed to an elevated risk of metastatic prostate cancer. Dairy product intake increased risk of metastatic prostate cancer (RR = 1.4, 95% CI = 0.91-2.2 for top vs. bottom quintile comparison), but no association remained after controlling for calcium and other fatty acids. A high intake in both red meat and dairy product was associated with a statistically significant two-fold elevation in risk of metastatic prostate cancer, compared to low intake of both products; however, most of the excess risk could be explained by known nutritional components of these foods., Conclusions: Intakes of red meat and dairy products appear to be related to increased risk of metastatic prostate cancer. While known nutrients, such as calcium and fatty acids, may explain most of the dairy association observed, it appears that a portion of the risk of metastatic prostate cancer associated with red meat intake remains unexplained.

Frequent consumption of meat has been associated with an increased risk of colorectal cancer. Such a risk may be due to naturally occurring compounds in the meat, substances added to the meat, or agents formed during cooking. Concerning the latter alternative, mutagenic heterocyclic amines are multi-site animal carcinogens, but their relevance to human cancer has yet to be determined. In the present study, we made a population-based inventory of cooked meat dishes consumed in the county of Stockholm, ranked dishes according to cooking method and frequency of consumption and, in addition, determined levels of mutagenic activity in six commonly consumed fried meat dishes. Meat was consumed, on average, 493 times per year, giving 1.4 daily servings. Frying was the most common way to cook meat. When ranking meat dishes according to intake frequency, the top eight dishes were as follows: sausage, steak casserole, meatballs, pork chops, pork belly, bacon, ground beef patties, and finally, mince-meat sauce. The frying sessions were performed under controlled conditions at four different temperatures, and we documented the degree of surface browning and measured mutagenic activity in six frequently eaten dishes (sausage, meatballs, pork chops, pork belly, ground beef patties, and minute beef). We found extracts from all six dishes to be mutagenic, and a mean daily dose of exposure was calculated, giving 862 revertants. This investigation leaves no doubt that a major portion of the total meat consumption is fried before ingestion and that fried meat dishes frequently consumed by an elderly population in Stockholm contain mutagenic substances. Furthermore, the study provides usable information for future epidemiological research in which it is necessary to disentangle the effect of meat per se from the effect of potentially carcinogenic heterocyclic amines.