Dietary vitamin D intake among university students and their habits concerning daily sunlight exposure – a cross-sectional study

Abstract

Aim: To evaluate students’ dietary vitamin D intake according to characteristics and habits concerning daily sunlight exposure. Methods: The study included 403 students of the University of Rijeka, Croatia that fulfilled questionnaire about their characteristics, habits, physical activity, supplement use, diet, and their daily sunlight exposure. For assessing diet quality, the Dietary inflammatory index (DII®) was used. Results: Average dietary vitamin D intake was 2.76 μg/day, statistically highest among men (p<0.01), medical sciences universities’ students (p<0.01), students with obesity (p=0.03), highly physically active (p=0.02) and smokers (p=0.01). Major dietary vitamin D sources were fish (42%, p<0.01) and meat and meat products (31%). Students that more frequently expose themselves to the sunlight were mostly men, overweight, moderately physically active, dietary supplements users, and had a diet with more anti-inflammatory potential, higher dietary vitamin D intake and its major dietary sources. Those who rarely and never used a sunscreen had a more anti-inflammatory diet and higher vitamin D and its major food sources intakes. Diet with more pro-inflammatory potential had students that rarely or never directly expose themselves to the sunlight, likewise the students that frequently used sunscreen. Those subgroups also had the lowest dietary vitamin D intake. Conclusions: The average dietary vitamin D intake by investigated university students satisfied only the fifth of the recommended daily vitamin D intake. Students with habits that can influence the lower synthesis of vitamin D may increase the risk of diseases related to bone health, immunity and inflammation in their future life. Provided results about students’ habits of their exposure to the sunlight might be useful for public health messages toward sufficient sunlight exposure, diet quality with more anti-inflammatory potential, vitamin D supplements use, and vitamin D deficiency prevention.