Diet-Focused Vitamin D Classes Boost Knowledge and Habits in Medical Students: RCT

A randomized controlled trial at Khoy University of Medical Sciences in West Azerbaijan, Iran, found that a short, diet-focused educational program substantially improved medical science students’ knowledge, attitudes, and self-reported practices related to vitamin D. The trial, published in BMC Nutrition, enrolled 132 students who were randomly assigned to an intervention or control group, with the largest gain seen in nutritional knowledge, historically the weakest component of vitamin D literacy among this population.

The study addressed a well-documented problem. According to the authors, vitamin D deficiency is a major public health issue worldwide, with a particularly high incidence among university students in the Middle East and Iran. Even though medical science students tend to have adequate general knowledge about the vitamin, significant gaps remain in the specific nutritional knowledge and everyday practices needed to maintain adequate vitamin D status.

The trial was designed as a parallel, randomized controlled trial with both participants and outcome assessors blinded to group allocation. Students were assigned by stratified block randomization, with allocation concealed in sequentially numbered, sealed, opaque envelopes. Sixty-six participants received the intervention and sixty-six served as controls. Vitamin D-related knowledge, attitudes, and practice were measured at baseline and again three months after the intervention using the validated D-KAP-38 questionnaire, and analysis of covariance was used to compare post-intervention scores while controlling for baseline differences.

The intervention itself consisted of four structured 60-minute sessions delivered over four consecutive weeks. The content combined foundational material on vitamin D physiology and sun exposure with a primary focus on dietary sources and culinary strategies for increasing vitamin D intake. To preserve blinding, control-group participants attended an equal number and duration of sessions on general health topics unrelated to vitamin D and calcium, delivered by the same facilitators in the same format.

Baseline results revealed an uneven profile of vitamin D literacy. Participants scored relatively high on general knowledge, averaging 86.16 percent, but substantially lower on nutritional knowledge, at 58.86 percent, and on practice scores, at 52.10 percent. This pattern confirmed that the students’ weakest areas were precisely the dietary and behavioral components the intervention was designed to target.

The control group improved less, gaining 7.99 percent in general knowledge, 4.73 in attitude, and 3.11 in self-reported practice, and showed no meaningful change in nutritional knowledge, where the 1.52 percent difference was not statistically significant.

The between-group comparison, adjusted for baseline scores, confirmed the advantage of the diet-focused program. Adjusted mean differences favored the intervention group across all four subscales: 8.30 for general knowledge (95 percent confidence interval 5.79 to 10.80), 20.62 for nutritional knowledge (14.82 to 26.43), 9.66 for attitude (6.53 to 12.79), and 7.80 for self-reported practice (5.19 to 10.40), all with p values below 0.001 and partial eta-squared values between 0.214 and 0.277, indicating sizable effects. The four subscales were treated as co-primary outcomes, and all four effects remained significant in a Bonferroni-adjusted sensitivity analysis with an alpha of 0.0125.

The authors concluded that a four-session, diet-focused educational intervention significantly improved self-reported vitamin D-related knowledge, attitudes, and practice among medical science students in Northwestern Iran, with the greatest gain in nutritional knowledge. Because the trial was part of a larger registry study that also assessed biochemical and academic outcomes, reported separately, the KAP findings sit within a broader research program rather than standing alone.

Important limitations temper the conclusions. The outcomes reported here are knowledge- and self-report-based, so they should be interpreted as evidence of improved knowledge, attitudes, and practice rather than proof of physiological benefit. Whether the observed increases are consistent with improved biochemical vitamin D status will be investigated in a companion report from the same trial. The authors also caution that the trial was registered retrospectively, on August 6, 2026, in the Iranian Registry of Clinical Trials under registration IRCT20260612069757N1; that the study relied exclusively on self-reported outcomes; that the primary analysis lacked multiplicity adjustment, though a Bonferroni sensitivity analysis was reported; and that the near-ceiling general-knowledge score at baseline may have limited room for improvement on that subscale.

Subject of Research: A randomized controlled trial of a diet-focused educational intervention on vitamin D knowledge, attitudes, and practice among medical science students in Northwestern Iran.

Article Title: Effect of structured, diet-focused educational intervention on knowledge, attitude, and practice related to vitamin D among medical science students: a randomized controlled trial

Article References: Karimi, M., Matin, H., & Olia, J. B. H. (2026). Effect of structured, diet-focused educational intervention on knowledge, attitude, and practice related to vitamin D among medical science students: a randomized controlled trial. BMC Nutrition. https://doi.org/10.1186/s40795-026-01526-7

Image Credits: AI Generated

DOI: 10.1186/s40795-026-01526-7

Keywords: vitamin D, randomized controlled trial, nutrition education, medical students, KAP questionnaire, Iran, dietary sources, self-reported practice, public health, health literacy, Effect, structured