Quince is not the first fruit that comes to mind when it comes to winter fruits, but its benefits do not end with counting. To strengthen your immune system in winter, consume this fruit, which is low in calories. In winter, with cold weather, we need to eat a rich diet of fruits and vegetables in order to protect our immune system against health problems. In winter, besides oranges and tangerines, quince deserves to be at the top of the table thanks to the vitamins and minerals it contains.