Vitamin D & Fibre Look for our bread & rolls that are a natural source of vitamin D and fibre. There are few dietary sources of vitamin D, so our bread is made with yeast that naturally produces it. The oats in this product have been carefully sourced to ensure they are free from gluten and gluten cross contamination. Oats may not be suitable for everybody following a gluten free diet. Source of vitamin D, which contributes to the maintenance of normal bones and teeth.