The study aimed to find the best foods to add vitamin D to and see how it would help older adults in Ireland. They looked at what older adults eat and how much vitamin D they get. By adding vitamin D to milk and bread, they found that it could increase vitamin D intake by 9-17 µg per day. If both milk and bread were fortified, about 70% of older adults could meet the recommended daily amount of vitamin D. Currently, most older adults in Ireland are not getting enough vitamin D from their diet. Adding vitamin D to common foods like milk and bread could help improve their intake.