Some doctors are recommending three portions of mussels a week to make the most of its omega-3 content. Mussels are extremely low in calories and very rich in nutrients like zinc. Mussels are one of our ultimate 'superfoods', according to a recent article in the Daily Mail. On top of this, mussels provide vitamins B2 and B12, phosphorous, copper, iodine and good amounts of omega three fats.