Is the intake of trans fat a problem in Norway today?
The report Development of the Norwegian diet 2012 states that the intake of trans fat has been greatly reduced (12). According to figures from consumer surveys, the intake has been reduced from 5 E % on average in 1958 to less than 1 E % today. This decline is largely accounted for by the reduction in the amount of trans fat in margarine (10). Meat from ruminants and full-fat dairy products are therefore currently the main sources of trans fat in foods produced in Norway (12). In a study from 2006, the average intake of trans fatty acids in Norway was estimated at 0.6 E % (13). This estimate was based on data on intake from a nationwide dietary survey (Norkost 97), the content of trans fatty acids stated in The Norwegian Food Composition Table, information from manufacturers and separate analyses.
Studies aiming to estimate the intake of trans fatty acids may have weaknesses that lead to an underestimation. Estimates of intake in consumer surveys include only foods purchased for the household, and not foods purchased in petrol stations, in kiosks or cafés or other catering establishments (14). The Norwegian Food Composition Table provides no data for a number of products supplied to the Norwegian market, and the information on the content of trans fat in the foods described in the table is also incomplete – for 150 of the 1 305 foods described (11.5 %) there is a lack of data on trans fat (7). This applies for example to foods that may contain a high proportion of trans fat, such as «microwave popcorn» and a number of types of biscuits and other baked goods (15). In addition, it is a known fact that the intake of foods considered to be «unhealthy» or which contain a lot of fat is often underreported in dietary surveys (16).
At the conference on diet and cardiovascular disease in Oslo on 24 – 25 January 2013, the Danish researcher Steen Stender presented the content of trans fat in various biscuit products purchased in November 2012 from a variety of shops in Oslo. The content of trans fat differed considerably between imported and Norwegian-made biscuits and cakes. For example, a daily intake of 100 grams of one of the imported biscuits (7 grams of trans fat per 100 gram of product) would result in trans fat accounting for 3 E % in the diet (Steen Stender, personal communication). If these products are consumed by children, the energy percentage will be significantly higher. Cakes and biscuits are subsumed in the category «processed grain and flour products», which is the group of foods that have seen the fastest growth in imports over recent years. In 2011, a full 25 % of the consumption in this category was in the form of imports (17).
The real intake of trans fat may therefore be higher than what is indicated by the estimates, especially in sub-groups of the population for whom ready-made meals, cakes and snack products predominate in the diet (15). A low average intake of trans fats at the population level does not exclude a high intake in sub-groups of the population, as long as products with a high content of trans fat are available on the market.
In general, it has been shown that people with a high level of education and high income tend to have a diet which is more health-promoting than is the case among people with less education and low income (18). One of the key priorities of the health authorities is to counterbalance social inequalities in health, meaning differences in health that consistently co-vary with level of education, income or profession (19, 20).