Preliminary Validation of a semi-quantitative Food Frequency Questionnaire (FFQ) to Assess Omega-3 Long Chain Polyunsaturated Fatty Acid Intakes in New Zealanders.

FFQ Development: An electronic, semi-quantitative FFQ has been developed to assess usual dietary intakes of foods containing n-3 LC-PUFA over the previous three months. The New Zealand Food composition database (2024) was used to find all foods that contained n-3 LC-PUFA. Food items that are contributors to n-3 LC-PUFA intake were identified and included in the FFQ (= 0.02 g/100 g). Internet searches and visits to local supermarkets were conducted to identify products fortified with EPA and/or DHA. Included food groups are seafood, meat, eggs, dairy products, baked goods/desserts, fast foods, condiments and sauces, and n-3 fortified products. Given the varying levels of n-3 LC-PUFA within food groups, specific New Zealand fish, shellfish and meat varieties are specified in the FFQ. The FFQ includes questions about specific cuts of lamb, beef, pork, venison and chicken, as well as offal meats. Questions are also asked about whether meat products are eaten with the fat trimmed, and if chicken is consumed with or without skin. Due to the wide variety of omega-3 and fish oil supplements available, open-ended questions are used to assess their intakes and the specific brand, EPA and DHA concentrations, and dose are asked for. The frequency of consumption of foods in the FFQ range from never, to intake per month, per week and per day. Diagrams, images of a food on a standard dinner plate (Crispim, Fisberg, Marchioni, & Steluti, 2017), and quantities (g) have been used to allow study participants to visualise and more accurately estimate portion sizes. The online electronic FFQ was created in Research Electronic Data Capture (REDCap), a secure online platform for building and managing survey data and has been pilot tested in 12 adults to ensure functionality and ease of use. The n-3 LC-PUFA intakes (g/day) generated from the FFQ will be total n-3 LC-PUFA, total n-3 LC-PUFA per food grouping, and intakes of EPA, DPA, and DHA. The FFQ takes between 10 to 20 minutes to complete (based on preliminary testing in 10 adults). Participants will complete the developed FFQ, mood questionnaires (PHQ-8 and GAD-7), weighed food records (Four days over 2 weeks) and blood spot collection at home. All questionnaires will be delivered electronically via REDCap. Once participants have provided written informed consent demographic information, and self-reported height (cm) and weight (kg) will be collected. A single drop of capillary blood (~1 mL) will be collected from each participant for the measurement of erythrocyte phospholipid n-3 LC-PUFA using dried blood spot (DBS) cards. Participants will complete the FFQ, and a 4-day weighed food record. Participants will complete the FFQ again three weeks later. Data collection will be underaken between November 2025 and February 2026.