M&S White Folded Flatbreads A natural source of Vitamin D and fibre, these soft folded flatbreads are baked in a traditional brick-lined oven for added flavour. Sprinkle with water and toast or grill. Four per pack. All of our breads are a natural source of Vitamin D and Fibre, two nutrients that are naturally low in our diets. We use a natural source of Vitamin D that is produced by yeast, which is why you will find ‘yeast’ on our list of ingredients, not because we use it as part of the dough making process.