Vitamin D, a crucial nutrient for strong bones, is more likely to be lacking in people who take oral corticosteroids. A study by researchers at Albert Einstein College of Medicine of Yeshiva University, in New York City, found that those on steroids have a vitamin D deficiency twice as often as people who don’t take one of these medications.

Because those with arthritis are often prescribed oral steroids, it is very important to ensure that your vitamin D levels are regularly checked if you’re on these drugs.

“Vitamin D can help regulate the immune system, ward off sickness and disease and if you’re taking medication that lowers immune system defenses it can help you from getting sick as often,” says nutritionist Karen Langston, a spokesperson for the National Association of Nutrition Professionals. “Vitamin D maintains blood calcium levels and it regulates calcium and phosphorus, which keep bones and teeth hard. Studies have found that women with the highest levels of vitamin D are 30 percent less likely to develop rheumatoid arthritis than women with lowest level of vitamin D.”

What does vitamin D deficiency cause?

“The biggest concern is osteomalacia, or the softening of the bones,” says Langston. “In children, it’s called rickets. It also can cause brittle bones, weak muscles. Other symptoms are fractures of the hip and pelvis, bone pain and tenderness, tooth decay and hearing loss because the bones in the ear become soft.”

Langston says you may have a vitamin D deficiency if you feel pain when you press on your breastbone also called the sternum, located in the middle of your chest.