Antti Aro

BACKGROUND: It has been suggested that mercury, a highly reactive heavy metal with no known physiologic activity, increases the risk of cardiovascular disease. Because fish intake is a major source of exposure to mercury, the mercury content of fish may counteract the beneficial effects of its n-3 fatty acids. METHODS: In a case-control study conducted in eight European countries and Israel, we evaluated the joint association of mercury levels in toenail clippings and docosahexaenoic acid (C22:6n-3, or DHA) levels in adipose tissue with the risk of a first myocardial infarction among men. The patients were 684 men with a first diagnosis of myocardial infarction. The controls were 724 men selected to be representative of the same populations. RESULTS: The average toenail mercury level in controls was 0.25 microg per gram. After adjustment for the DHA level and coronary risk factors, the mercury levels in the patients were 15 percent higher than those in controls (95 percent confidence interval, 5 to 25 percent). The risk-factor-adjusted odds ratio for myocardial infarction associated with the highest as compared with the lowest quintile of mercury was 2.16 (95 percent confidence interval, 1.09 to 4.29; P for trend=0.006). After adjustment for the mercury level, the DHA level was inversely associated with the risk of myocardial infarction (odds ratio for the highest vs. the lowest quintile, 0.59; 95 percent confidence interval, 0.30 to 1.19; P for trend=0.02). CONCLUSIONS: The toenail mercury level was directly associated with the risk of myocardial infarction, and the adipose-tissue DHA level was inversely associated with the risk. High mercury content may diminish the cardioprotective effect of fish intake.

The 4th edition of the Nordic Nutrition Recommendations, NNR 2004, gives the proportions between energy yielding nutrients, recommended daily intakes (RI) of certain vitamins and minerals, and reference values for energy intakes in different age and sex groups. Recommendations are also given for dietary fibre, salt and alcohol. Recommendations on daily physical activity are now included and interaction with physical activity has been taken into account for the individual nutrient recommendations wherever appropriate. For adults 30minutes of daily physical activity of at least moderate intensity is recommended. More physical activity (about60 minutes daily) with a moderate and/or vigorous intensity may be needed for prevention of weight gain. For children a minimum of 60 minutes of physical activity every day is recommended. As in the 3rd edition, the recommendation is to limit of the intake of saturated plus trans fatty acids to about 10% of the total energy intake (E%) and of the total fat intake to 30 E%. The intake of carbohydrate and dietary fibres should increase, while the intake of refined sugars should not exceed 10 E%. The RI for vitamin A (women) has been lowered, while it has been increased for vitamin D (children and adults up to 60 y), vitamin C (adults) and folate (women of reproductive age; pregnant and lactating women).NNR is to be used for planning and evaluation of diets, and as a basis for food and nutrition policy, teaching and dietary information. Keywords: nutrition recommendations; physical activity; vitamins; minerals; Nordic countries

BACKGROUND: Fat accumulation in the liver has been shown to be closely correlated with hepatic insulin resistance and features of insulin resistance, even independent of body weight. The reason for interindividual variation in liver fat content is unknown. Cross-sectional data suggest that dietary fat content may influence liver fat, but this possibility has not been directly tested in humans. DESIGN AND METHODS: Liver fat (proton spectroscopy), intraabdominal and sc fat (magnetic resonance imaging), and markers of insulin sensitivity (insulin, free fatty acids, and lipids) were determined in 10 normal, obese women (age, 43 +/- 5 yr, mean +/- sd; body mass index, 33 +/- 4 kg/m2; range, 27-38 kg/m2) at baseline and after two 2-wk isocaloric periods containing either 16% (low-fat diet) or 56% (high-fat diet) of total energy as fat. RESULTS: Liver fat at baseline averaged 10 +/- 7%. It decreased by 20 +/- 9% during the low-fat diet and increased by 35 +/- 21% during the high-fat diet (P = 0.014 for liver fat after low- vs. high-fat diets; P = 0.042 for change in liver fat by the low- vs. high-fat diet). Fasting serum insulin averaged 70 +/- 41 pmol/liter at baseline. It decreased to 60 +/- 24 pmol/liter during the low-fat diet (P = 0.007 vs. before low-fat diet) and increased to 81 +/- 44 pmol/liter during the high-fat diet (P = 0.040 vs. before high-fat diet; P = 0.005 for change in serum insulin during low- vs. high-fat diet). Serum lipids, free fatty acids, and intraabdominal and sc fat masses were unchanged. CONCLUSION: These data suggest that the amount of dietary fat influences liver fat content.