My son is 1+ now, he has low immunity What food I can give him that boost his immunity?

A. Immunity boosting foods : Red bell peppers : beta carotene, Vitamin C Citrus fruits : Vitamin C Berries : anti oxidants lean protein such as chicken : iron and zinc legumes like beans, chickpeas and lentils yoghurt avocados : healthy fats and Vitamin E sunflower seeds : iron and vitamins almonds : Vitamin E and manganese