Fruits to Boost Immunity in Winter: While the winter season brings relief from the scorching heat, it also brings with it many types of infections and viral diseases. People are troubled by cold, cough, sore throat, fever, pneumonia, mosquito-borne diseases in this season. In such a situation, it is necessary to boost immunity in cold. For this, include citrus fruits available in winter in your diet. Citrus fruits are rich in Vitamin C, which strengthens the immune system and gives your body the strength to fight diseases and infections. By consuming these five fruits, you can boost your immunity and keep yourself healthy in cold.