Dietary Intake in Adults From the GA2LEN Folow-up Survey

Within the GA2LEN Follow-up Survey, the Nutrition Survey was aimed at assessing dietary intake in adults across European countries and its association with various outcomes of allergy and respiratory health. In absence of an internationally comparable dietary questionnaire to ascertain usual dietary intake, a single and standardized food frequency questionnaire (FFQ) was design to be used as a common instrument in all participant countries. The FFQ is comprised of 32 food sections and 250 food items. The FFQ sections were designed following the recommendations by the EFCOSUM Group, which facilitate international comparisons of dietary intake. It also included several staple foods to capture locally representative dietary intake. Participants reported how often they had consumed each of the foods over the previous month, using eight predefined options (rarely or never, 1-3 times per month, once, 2-4, or 5-6 times per week, once, 2-3 times per day). Standard food portion sizes were used to quantify the intake following the recommendations from the UK's Food Standards Agency. Daily intake of foods (g) were estimated and macro- and micronutrient and flavonoid intakes were derived. The GA2LEN FFQ was validated in five EU countries, namely Finland, UK, Portugal, Germany, Poland, and Greece, and demonstrated to be a good tool to assess mid-term intake of foods, specifically essential polyunsaturated fatty acids (PUFAs). The instrument has also been demonstrated to be an accurate tool to assess dietary sources of flavonoids. Various approaches were planned to derive dietary exposures and to examine their association with respiratory and allergic outcomes. These included the use of dietary patterns derived from Principal Component Analysis (PCA), a dietary inflammatory index (DII), as well as single antioxidants, and individual food items.