Dietary Supplement Use Among Croatian Vegans Assessed by the Dietary Supplement Inventory (DSI): A Cross-Sectional Study

Background and aim: Vegan diet, i.e., total restriction of foods of animal origin, might lead to challenges regarding adequacy of intake of several nutrients, including vitamin B12, vitamin D, iron, calcium, omega-3 fatty acids, and zinc. Therefore, dietary supplements are often recommended. However, supplement use patterns among vegans in Croatia remain underreported. The aim of this study was to assess dietary supplement use patterns and reasons for their use among adult vegans in Croatia using the Dietary Supplement Inventory (DSI) approach. Methods: A cross-sectional study included 49 adult vegans (28 female, 21 males; aged 18-60 years) between January and April 2025. Data were collected through structured interviews based on the DSI method, documenting supplement products found in participants' homes, their composition, dosages, and use. Descriptive and selected inferential statistics were used. Results: The majority of participants (86%) reported using at least one dietary supplement, and 49% used supplements daily. Vitamins were the most frequently used supplement category (43%). Only 22% of participants reported vitamin B12 supplementation. Other commonly consumed supplements included amino acids (35%), minerals such as calcium and magnesium (35%), herbal extracts (24%), probiotics (14%), and omega-3 fatty acids (14%). Men used fewer supplements overall and were more likely than women to report non-use. Most participants used four or five supplements concurrently (56%). Conclusions: Although most vegans use supplements, vitamin B12 supplementation was unexpectedly low given its position as the critical micronutrient in a vegan diet. These findings highlight the need for targeted nutrition education regarding appropriate supplementation among vegans in Croatia.