You’re Getting Sick More Often Than You Normally Would
One of the key functions of vitamin D is keeping your immune system healthy. When your immune system is strong, you are better able to fight off infections and illnesses that are caused by viruses and bacteria. If you are deficient in vitamin D, your immune system is weakened, which means that you will become more susceptible to illnesses and infections.
If you are contracting things like the flu, the common cold, strep throat or other infections and illnesses more frequently than you normally would, it could be because you are not getting enough vitamin D. You might also run the risk for developing chronic disorders, such as COPD. One study found that people who have COPD were highly deficient in vitamin D.