The National Food Administration has long been aware of the problem of dioxins in foodstuff. As early as the beginning of the 1980s, dietary recommendations were introduced concerning fish with elevated levels of organochlorine environmental toxins. Commercial- and recreational fishermen and their families have been identified as possible risk groups with a high consumption of dioxin-contaminated fish. Among these, above all children and women in their childbearing years should limit their consumption.
Dietary recommendations for groups at risk
Threshold values for dioxins in food are one tool for measures against the sale of foodstuff contaminated with high levels of dioxins. However, the limits do not prevent the group at most risk (girls and women of commercial- and recreational fishing families) from eating fish caught by their families. Following the dietary recommendations concerning contaminated fish will give these risk groups adequate protection from a high dioxin intake, at the same time as retaining the nutritional advantages of having fish in their diet. From a public health standpoint, the consumption of fish is generally beneficial.
Decrease average dioxin intake by half
Emissions of dioxins from combustion processes and the chemicals industry have been significant sources of contamination to Swedish foodstuff. Owing to decisive steps taken against emissions, today’s population is exposed to considerably fewer dioxins than in the beginning of the 1970s.
National Food Administration investigations of dioxin intake from food suggest that the average intake has decreased by half over the past 15 years (Darnerud et al., 2000a). Dioxin levels in breast milk, which is a measure of the dioxin concentration in a woman’s body during pregnancy, have fallen to one fifth of the levels measured in the 1970s in the Stockholm-Uppsala area (Norén and Meironyté, 2000; Glynn et al., 2001).
Low consumption of herring
The average consumption of herring and wild salmon from the Baltic is at present low in Sweden. A National Food Administration dietary study from the late 1990s (Riksmaten 1997-98) showed that women between the ages of 17-44 years ate herring an average of four times per year. The average consumption of Baltic salmon was approx. two times per year.
Approx. 14% of women in the age group 17-44 were classified as high consumers, i.e., with a consumption of herring and Baltic salmon above the recommendations. It was primarily the older women of this age group who ate most fish. In a 2001 environment-health report (Miljö-hälsorapport 2001), the National Board of Health and Welfare reports that only 6% of Swedish women in the age group 19-45 eat herring at least once per month.
Among men and older women, the average consumption of herring and Baltic salmon is about 1-1.5 servings per month, which can be compared to the recommended intake for this group of once per week.
Average intake half of the tolerable limit
In the EU, a tolerable weekly dioxin intake of 14 picogram (pg) WHO-TEQ/kg bodyweight has been set by specialists from the Scientific Committee on Food. The tolerable intake represents the level considered safe over a lifetime of consumption and is calculated with the use of safety margins. The team of experts does not view exceeding the tolerable intake limit for a brief period as carrying any increased risk to health.
Results from a study on the dioxin intake of pregnant women in the Uppsala area conducted by the National Food Administration indicate that the average intake is about half of the tolerable weekly intake. Only a small number of women showed an intake in slight excess of the tolerable limit.
Herring and salmon represent a small part of total dioxin intake
The average intake of dioxins in the Swedish population as a whole is at present 9-13 pg/kg bodyweight/week (Darnerud et al., 2000b; SCOOP, 2000). This can be compared to a reported average dioxin intake in Great Britain of 14 pg/kg bodyweight/week (1992) (SCOOP, 2000). The same report shows an intake in the Netherlands of 10 pg/kg/week (1994), Finland 13 pg/kg/week (1991-99) and Norway 14 pg/kg/week (SCOOP, 2000). The Scientific Committee on Food reports an average intake in Europe of 8-21 pg/kg bodyweight/week (SCF, 2001).
Overall, the consumption of fish in Sweden contributes on average to over 30% of the total dioxin intake of which herring and Baltic salmon represent approx. 17% (Darnerud et al., 2000a). However, ongoing studies may show an increase in the fish contribution to the total dioxin intake.
References
Darnerud PO, Atuma S, Aune M, Becker W, Petersson-Grawé K, Wicklund-Glynn A (2000a) Mindre dioxin i svenska livsmedel. (‘Less dioxin in Swedish foodstuff’) Vår Föda 52 (No. 1), 26-29.
Darnerud PO, Atuma S, Aune M, Becker W, Petersson-Grawé K, Wicklund-Glynn A (2000b) Organiska miljökontaminanter i svenska livsmedel.(‘Organic environment contaminants in Swedish food products’) Specialist report to Environmental Monitoring, Swedish Environmental Protection Agency; 36 pages.
Glynn A, Atuma S, Aune M, Darnerud PO, Cnattingius S (2001) Polychlorinated biphenyl congeners as markers of toxic equivalents of polychlorinated biphenyls, dibenzo-p-dioxins and dibenzofurans in breast milk. Environ. Res. Section A 86, 217- 228.
Norén K and Meironyté D (2000) Certain organochlorine and organobromine contaminants in Swedish human milk in perspective of past 20-30 years. Chemosphere 40, 1111-1123.
SCOOP (Scientific Co-operation on Questions Relating to Food) (2000) Assessment of dietary intake of dioxins and related PCBs by the population of EU Member States. Directorate-General Health and Consumer Protection, 7 June 2000.
SCF (Scientific Committee on Food) (2001) Opinion of the SCF on the risk assessment of dioxins and dioxin-like PCBs in food – update based on new scientific information available since the adoption of the SCF opinion of 22nd November 2000 (CS/CNTM/DIOXIN/20 REV 6 final)