Fish oil users of Greece: Predictors, knowledge and habits regarding dietary supplement use

Fish oil (FO) dietary supplements (DS) have gained popularity over the past few decades and emerged as one of the most popular DS in both Europe and the USA. However, in Greece, no study has been carried out to determine the prevalence and characteristics of FO consumers.

The aim of this study was to describe the stance (i.e., beliefs, knowledge and habits) and practices of FO users in Greece towards DS.

A cross-sectional study, using in-person questionnaires and a stratified random sampling technique, was conducted throughout 2018–2019. A total of 28.491 Greek citizens over 15 years old were interviewed in 74 regional units corresponding to the 13 administrative regions of Greece. Having used DS at least once, deemed one as: DS+FO, if FO were among them; DS-FO, if FO were never used or DS non-user, if DS were never used. Pearson's chi-square test was used to determine independence between relevant outcome variables and FO use and multinomial logistic regression was performed to create models predictive of FO use.

The sample consisted of 3.5% DS+FO, 51.3% DS-FO and 43.8% DS non-users, while 1.4% could not remember whether they had used DS. Significant predictors for being a DS+FO were identified. DS+FO were more likely to judge a DS-less diet as insufficient, support DS use and comprehend DS's labels. Also, DS+FO had used additional DS, considered more parameters when buying DS and were receivers of DS recommendations from more sources compared to DS-FO. 90% of DS users seek at least one approval source of their DS and 50% support DS recommendation by doctors.

Favorableness towards DS is more prevalent among DS+FO. Most respondents lack knowledge about the legislative background of DS and many would agree to professional guidance.