The introduction of the habit of daily beef consumption among Japanese immigrants and their descendants may be associated with stomach cancer risk. The protective effect of fruit consumption was confirmed in this population.

Heterocyclic amine (HCA) concentrations were measured in meat and fish samples cooked by panfrying, grilling and churrasco (Brazilian barbecue) to various levels of doneness in accordance with the cooking methods most commonly used in Brazil. HCAs were extracted by the Blue-rayon absorption method and measured by liquid chromatography-mass spectrometry. 2-Amino-1-, and 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx) were sharply increased in very well-done meats and fish. HCA levels varied somewhat across cooking methods: levels of PhIP (ng/g) in very well-done, non-marinated samples were particularly high for churrasco (31.8 in the exterior of the sample), compared to lower levels for grilled (16.3), and panfried beef (0.58). On comparison across foods, chicken contained higher HCA levels than other nonmarinated samples. For example, PhIP levels (ng/g) in very well-done pan-fried foods were 34.6 for chicken with the skin, 0.58 for beef, 7.25 for pork, 2.28 for sardines, and 7.37 for salmon cooked with the skin. HCA levels were lower in marinated meats and fish than in non-marinated samples, except for pan-fried salmon. This study provides valuable information which will allow the estimation of dietary HCA exposure using an epidemiologic questionnaire and the investigation of the association of HCA intake with cancer risk in Brazil.

BackgroundSeveral studies have determined that dietary intake of B vitamins may be associated with breast cancer risk as a result of interactions between 5,10-methylenetetrahydrofolate reductase (MTHFR) and methionine synthase (MTR) in the one-carbon metabolism pathway. However, the association between B vitamin intake and breast cancer risk in Brazilian women in particular has not yet been investigated.MethodsA case-control study was conducted in São Paulo, Brazil, with 458 age-matched pairs of Brazilian women. Energy-adjusted intakes of folate, vitamin B6, and vitamin B12 were derived from a validated Food Frequency Questionnaire (FFQ). Genotyping was completed for MTHFR A1298C and C677T, and MTR A2756G polymorphisms. A logistical regression model was used to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs).ResultsNeither dietary intake of folate, vitamin B6, or vitamin B12 nor MTHFR polymorphisms were independently associated with breast cancer risk. Analysis stratified by menopausal status showed a significant association between placement in the highest tertile of folate intake and risk of breast cancer in premenopausal women (OR = 2.17, 95% CI: 1.23–3.83; Ptrend = 0.010). The MTR 2756GG genotype was associated with a higher risk of breast cancer than the 2756AA genotype (OR = 1.99, 95% CI = 1.01–3.92; Ptrend = 0.801), and statistically significant interactions with regard to risk were observed between the MTHFR A1298C polymorphism and folate (P = 0.024) or vitamin B6 (P = 0.043), and between the MTHFR C677T polymorphism and folate (P = 0.043) or vitamin B12 (P = 0.022).ConclusionMTHFR polymorphisms and dietary intake of folate, vitamin B6, and vitamin B12 had no overall association with breast cancer risk. However, increased risk was observed in total women with the MTR 2756GG genotype and in premenopausal women with high folate intake. These findings, as well as significant interactions between MTHFR polymorphisms and B vitamins, warrant further investigation.

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