Changes in diet quality and its association with students' mental state during two COVID-19 lockdowns in Croatia.

Background: The COVID-19 pandemic has left substantial consequences on the mental health of the student population, primarily through an increase in the symptoms of acute stress and anxiety. Aim: This study evaluated diet quality and its association with mental state among Croatian students during the spring and winter COVID-19 lockdowns in 2020. Methods: Data were collected using an anonymous online self-reported questionnaire taken on two occasions. During the spring lockdown (from May 18 to June 7, 2020) and the winter lockdown (from December 14-22, 2020), 751 and 1188 students completed the questionnaire, respectively. Diet quality was determined using the pro-healthy diet index (pHDI) and non-healthy diet index (nHDI). Results: Although to the greatest extent associated with increased white meat, fish, and legumes intake, an increase in pHDI was also linked to increased consumption of water and sweets and decreased intake of processed meat products and nuts. Increased nHDI was mainly due to increased intake of processed meat products, alcohol, and sweets. Moreover, diet quality was higher during the lockdowns than in the periods before. However, diet quality increased to a lesser extent during the winter lockdown and was associated with a poorer mental state, shown as type D (Distressed) personality. Type D personality positively correlated with nHDI and sweets intake but negatively with pHDI, fruit, and vegetable consumption. Conclusion: These results indicate the need to alleviate further students' diet quality and mental state impairment. Also, further investigation of the association between diet quality and mental state should be provided.