Vitamin A is an essential vitamin for a healthy immune system. This vitamin helps to keep the mucous membranes that line the respiratory and gastrointestinal tracts functioning properly. Vitamin A also plays a role in producing white blood cells, which are critical for fighting infection.
A deficiency in vitamin A can lead to a number of health problems, including increased susceptibility to infection. Therefore, it is important to make sure that you are getting enough of this nutrient in your diet. Foods rich in vitamin A include carrots, sweet potatoes, spinach, and kale.