The intake of polyunsaturated fatty acids and cardiovascular diseases

Background Despite a large amount of research in the past decades, the role of polyunsaturated fatty acids (PUFA) in the prevention of coronary heart disease (CHD) and stroke is still debated. Inconsistent findings in epidemiological studies may be due to methodological limitations of dietary assessment, which could be overcome by using PUFA levels in blood as a biomarker of intake. This thesis investigates dietary intake and plasma levels of various n-6 and n-3 PUFA in relation to CHD and stroke within a population-based sample in the Netherlands. Methods The associations of dietary intake of PUFA (assessed by food-frequency questionnaire) with incident CHD and stroke were examined in cohort studies. PUFA levels in plasma cholesteryl esters were measured in nested case-control studies. N-6 PUFA included linoleic acid and arachidonic acid and the n-3 PUFA included the marine-derived eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and the plant-derived alpha-linolenic acid (ALA). We used the “Monitoring Project on Cardiovascular Disease Risk Factors“ and the “Monitoring Project on Risk Factors for Chronic Diseases” (MORGEN study), two large similar population-based cohorts with baseline measurements in 1987-1997 and follow-up for CHD and stroke incidence. Additionally, we performed a meta-analysis of prospective epidemiological studies on PUFA in cholesteryl esters and CHD risk. Results A 4-5 en% difference in linoleic acid intake was not associated with incident CHD, whereas plasma linoleic acidwas inversely, but statistically non-significantly, associated with fatal CHD. In the meta-analysis, a 5% higher plasma linoleic acid level was related to a significant 9% lower CHD risk. Both ALA intake and status were not associated with CHD. The top quartiles of EPA-DHA (~250 mg/d) and fish intake (~1 fish meal/week) were related to a ~50% lower risk of fatal CHD compared to the bottom quartiles. However, this was not confirmed in plasma EPA-DHA. An ALA intake ≥1.1 g/d was associated with a 35-50% lower stroke incidence, compared with lower intakes. In women, but not in men, a significantly inverse relation was observed for EPA-DHA and fish intake with incident stroke, with a ~50% lower risk in the top quartile compared with the bottom quartile. Plasma PUFA levels were, however, not related to incident stroke. Conclusion The hypothesis of a beneficial effect of linoleic acid on CHD was confirmed in our biomarker study, but not in the study that used dietary intake data. For EPA-DHA, on the other hand, dietary intake was inversely related to fatal CHD and incident stroke, whereas cholesteryl ester EPA-DHA were not associated. The same applied to ALA intake in relation to incident stroke. Inconsistencies between PUFA intake and status with cardiovascular diseases could be attributed to the limited range of variation in PUFA intake in combination with measurement error. </p

Linoleic acid intake, plasma cholesterol and 10-year incidence of CHD in 20.000 middle-aged men and women in the Netherlands

We studied the associations of a difference in linoleic acid or carbohydrate intake with plasma cholesterol levels and risk of CHD in a prospective cohort study in the Netherlands. Data on diet (FFQ) and plasma total and HDL-cholesterol were available at baseline (1993–7) of 20 069 men and women, aged 20–65 years, who were initially free of CVD. Incidence of CHD was assessed through linkage with mortality and morbidity registers. During an average of 10 years of follow-up, 280 CHD events occurred. The intake of linoleic acid ranged from 3·6 to 8·0 % of energy (en%), whereas carbohydrate intake ranged from 47·6 to 42·5 en% across quintiles of linoleic acid intake. Linoleic acid intake was inversely associated with total cholesterol and HDL-cholesterol in women but not in men. Linoleic acid intake was not associated with the ratio of total to HDL-cholesterol. No association was observed between linoleic acid intake and CHD incidence, with hazard ratios varying between 0·83 and 1·00 (all P>0·05) compared to the bottom quintile. We conclude that a 4–5 en% difference in linoleic acid or carbohydrate intake did not translate into either a different ratio of total to HDL-cholesterol or a different CHD incidenc

Soil biological quality of grassland fertilized with adjusted cattle manure slurries in comparison with organic and inorganic fertilizers

We studied the effect of five fertilizers (including two adjusted manure slurries) and an untreated control on soil biota and explored the effect on the ecosystem services they provided. Our results suggest that the available N (NO3- and NH4+) in the soil plays a central role in the effect of fertilizers on nematodes and microorganisms. Microorganisms are affected directly through nutrient availability and indirectly through grass root mass. Nematodes are affected indirectly through microbial biomass and grass root mass. A lower amount of available N in the treatment with inorganic fertilizer was linked to a higher root mass and a higher abundance and proportion of herbivorous nematodes. A higher amount of available N in the organic fertilizer treatments resulted in a twofold higher bacterial activity (measured as bacterial growth rate, viz. thymidine incorporation), a higher proportion of bacterivorous nematodes, a 30% higher potential N mineralization (aerobic incubation), and 25–50% more potentially mineralizable N (anaerobic incubation). Compared to inorganic fertilizer, organic fertilization increased the C total, the N total, the activity of decomposers, and the supply of nutrients via the soil food web. Within the group of organic fertilizers, there was no significant difference in C total, abundances of soil biota, and the potential N mineralization rate. There were no indications that farmyard manure or the adjusted manure slurries provided the ecosystem service “supply of nutrients” better than normal manure slurry. Normal manure slurry provided the highest bacterial activity and the highest amount of mineralizable N and it was the only fertilizer resulting in a positive trend in grass yield over the years 2000–2005. The number of earthworm burrows was higher in the treatments with organic fertilizers compared to the one with the inorganic fertilizer, which suggests that organic fertilizers stimulate the ecosystem service of water regulation more than inorganic fertilizer. The trend towards higher epigeic earthworm numbers with application of farmyard manure and one of the adjusted manure slurries, combined with the negative relation between epigeic earthworms and bulk density and a significantly lower penetration resistance in the same fertilizer types, is preliminary evidence that these two organic fertilizer types contribute more to the service of soil structure maintenance than inorganic fertilize

In the Shadow of Asylum Decision-Making: The Knowledge Politics of Country-of-Origin Information

Country-of-origin information has secured a central place in European asylum systems, underpinning state decisions on the asylum status of refugee populations. All European states produce this type of information, and dedicated country-of-origin information units are increasingly common. This article analyzes the knowledge politics of country-of-origin information, with a focus on the relation between knowledge and decision. We are interested in this type of knowledge precisely because it is uneasily positioned in-between social scientific methodology and policy decision-making and is infused with a “pulsional normativity.” We distinguish three phases of country-of-origin information production: first, a phase of investigation, where foreign lands are reduced to stable and mobile forms so that they can be studied as research units; second, the concordance of information production, relying on standardized instruments and practical skill; and third, the consolidation phase, which involves the return of country information constructed inside research units back into the administrative and regulatory world. The final section of the article examines how complex and frail information about countries of origin becomes deployed as valid grounds for asylum decision-making