M&S Remarksable Small White Pittas A natural source of Vitamin D and fibre, these soft pittas are perfect for dipping or add your favourite filling for a quick and tasty lunch. Microwave or grill. Suitable for vegetarians and vegans. 12 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.