Fish oil users of Greece: reasons, appropriate use and perceived results regarding dietary supplement use

The aim of this cross-sectional study was to explore differences regarding the reasons, appropriate use, and perceived results relating to dietary supplement (DS) use between DS users who have used fish oils (FO) among other DS (DS + FO) and DS users who have used DS other than FO (DS - FO). Using a stratified random sampling technique, throughout 2018-2019, data was collected via in-person questionnaires. Having used any DS at least once, one was deemed a DS user, defined as "DS + FO" or "DS - FO" if FO were present or absent among the reported DS, respectively. The final sample consisted of 15,608 DS users. Independence between DS use status and categorical outcome variables was determined via Pearson's chi-square test. Regarding DS users, 48.3 and 32.1% were medically supervised before and during DS use, respectively, with more DS + FO self-assessing themselves during, e.g., blood tests (21.6 vs. 17.1%). More DS + FO used DS systematically for > 1 month (42.9 vs. 30.8%) and selected more reasons for DS use (>= 3; 47.6 vs. 25.4%). Most DS users experienced no negative outcomes from DS use (73.0%), but at least one positive outcome (95.8%), with DS + FO selecting a higher number of the latter (>= 2; 55.7 vs. 38.0%). More DS + FO believed that a balanced diet (without DS) could not ensure their desired results (25.5 vs. 20.1%) but displayed a higher prevalence of recommended dietary allowance adherence (82.1 vs. 78.5%) and knowledge of the dangers of DS overuse (53.6 vs. 48.4%). Our study reveals significant differences between DS + FO and DS - FO with regard to their consumer stance and behavior towards DS.