A new review of national dietary surveys shows that vitamin intakes below recommended levels arecommon in representative Western populations in countries such as Germany, the UK, the Netherlands, and the USA.
In the review (1), vitamin intake data for adults from the most recently published large dietary-intake sur-veys for Germany (2), the UK (3), the Netherlands, (4) and the USA (5) were compared with the respective national intake recommendations. Intake data were evaluated excluding dietary supplements to assess the quality of the diet. The proportions of the populations with intakes below recommended levels were catego-rized as below 5 %, 5 to 25 %, 25 to 50 %, 50 to 75 %, and above 75 % for each vitamin. The data gene-rated were presented in a ”traffic light display”, using colors from green to red to indicate degrees of suffi-ciency.
The researchers concluded that although inter-country differences exist, intakes of several vitamins are below recommended levels for a significant proportion of the population in all these countries. The most critical vitamin appears to be vitamin D and the least critical is niacin. The variation between the countries is most probably due to differences in recommendations, levels of fortification, and local dietary habits. As a gap exists between vitamin intakes and requirements for a significant proportion of the population, even though diverse foods are available, there is a need to investigate ways to correct this gap. They added that the use of vitamin supplements has increased over the last few decades and that, consequently, its effect has to be considered. While dietary supplements have decreased the number of individuals not achieving the recommended intakes in the USA, a significant proportion still has insufficient intakes for vitamins A, C, D, E, and K (6). Supplement use in Europe is less common and, in addition, there is a strong north-to-south gradi-ent, with 40 and 5 % users, respectively (7), which corresponds with the range of 25–50 % reported in the three European surveys evaluated. Recategorizing the intake data with supplements had no noticeable im-pact on the ”traffic light display” score for the UK data, but resulted in a slight shift towards lower prevalence for the Dutch survey. The German report did not include the impact of the supplements on total intake.
Although national dietary reference values vary considerably in their terminology and values, the concept that underlies these dietary intake recommendations is similar. While the recommendations were previously defined to prevent overt deficiencies, nowadays, dietary reference intakes aim to define the intake at which health, including the reduction of chronic diet-related diseases, is optimal for the majority of individuals (generally 97.5 %) of a given population or group. Despite the existence of these intake recommendations, it is not fully clear how good the nutritional status in Western populations is. On the one hand, a variety of different kinds of foods are available and accessible for everybody. On the other hand, changing lifestyles, reduced physical activity, indoor living and an increase in fast and convenience food with a low micronutrient density may have an impact on the quality of a person’s daily diet and hence on their nutritional status (8).