A Household-Based Dietary Intervention Study of Vitamin D Fortified Bread in Irish Families

Vitamin D deficiency is common. It is caused by limited sun availability together with a low supply of vitamin D in the food system. There is a high prevalence of low vitamin D status around the world. In Ireland, our relatively northern latitude and prevailing weather mean that UVB availability for skin synthesis of vitamin D is limited in this country and our population relies on the dietary supply of vitamin D to prevent deficiency. Thus, the endemic Irish problem of vitamin D malnutrition is due to the lack of vitamin D in our food system. Dietary guidelines cannot address this issue because foods naturally rich in vitamin D are very few and infrequently consumed. The FamDBread study will test the hypothesis that a vitamin D-fortified bread as part of a healthy diet that includes vitamin D-fortified foods is effective in preventing low vitamin D status during winter, and safe for families to consume.

NCT Number	NCT07481240
Lead Sponsor	University College Cork Collaborators: University College Dublin
Conditions	Vitamin D Deficiency
Enrollment	128 participants
Start Date	2025-11-17
Primary Completion	2026-04-04 (estimated)
Study Completion	2026-04-04 (estimated)
Updated on ClinicalTrials.gov	2026-05-15