BACKGROUND: A beneficial role of fish consumption on the risk of myocardial infarction (MI) has been reported, mostly ascribed to n-3 (omega-3) fatty acids. However, fish also contains methylmercury, which may increase the risk of MI.

OBJECTIVE: The objective was to determine how fish consumption and erythrocyte concentrations of mercury (Ery-Hg) and selenium (Ery-Se) are related to the risk of MI and whether n-3 fatty acids (eicosapentaenoic and docosahexaenoic acids) in plasma phospholipids (P-EPA+DHA) are protective.

DESIGN: This was a case-control study nested within the northern Sweden cohort, in which data and samples were collected prospectively. The study included 431 cases with an MI after data and sample collection, including 81 sudden cardiac deaths (SCDs) and 499 matched controls. Another 69 female cases with controls from a breast cancer screening registry were included in sex-specific analyses.

RESULTS: Odds ratios for the third compared with the first tertile were 0.65 (95% CI: 0.46, 0.91) for Ery-Hg, 0.75 (95% CI: 0.53, 1.06) for Ery-Se, and 0.78 (95% CI: 0.54, 1.11) for P-EPA+DHA. Ery-Hg and P-EPA+DHA were intercorrelated (Spearman’s R = 0.34). No association was seen for reported fish consumption. Multivariate modeling did not change these associations significantly. Sex-specific analyses showed no differences in risk associations. High concentrations of Ery-Se were associated with an increased risk of SCD.

CONCLUSIONS: The biomarker results indicate a protective effect of fish consumption. No harmful effect of mercury was indicated in this low-exposed population in whom Ery-Hg and EPA+DHA were intercorrelated.

Wennberg M, Bergdahl IA, Hallmans G, Norberg M, Lundh T, Skerfving S, Strömberg U, Vessby B, Jansson JH.

Department of Medicine, Skellefteå Hospital, Skellefteå, Sweden.

m J Clin Nutr. 2010 Nov 3.

Prostate cancer has become a major public health problem worldwide. Yet, the etiology of prostate cancer remains largely unknown. Dietary factors, dietary supplements, and physical activity might be important in the prevention of the disease. In the majority of studies, it was observed that high consumption of meat and dairy products has been linked to a greater risk. In contrast, frequent consumption of fatty fish and tomato products has been associated with a reduced risk. It has been shown consistently that high levels of circulating insulin-like growth factor 1 (IGF-1) are associated with an increased risk of prostate cancer. Dietary factors are also recognized as determinants of circulating IGF-1, thus changes in diet may influence IGF-1 concentrations in serum. Furthermore, increased intake of vitamin E and selenium (from supplements) has been shown in intervention studies to decrease the risk. Possibly, high level of physical activity is also associated with decreased risk of prostate cancer. The accumulated scientific evidence concerning the associations between diet, lifestyle, and risk of prostate cancer development suggests that there are some identified modifiable risk factors that it might be recommended to change in order to decrease the risk for this common cancer site.

Wolk A.

Division of Nutritional Epidemiology, the National Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden. Alicja.Wolk@imm.ki.se

Acta Oncol. 2005;44(3):277-81.Links