Boils usually do not mean your body is lacking a specific vitamin or mineral. They are most often caused by a bacterial infection in a hair follicle, commonly involving Staphylococcus aureus. Many people who get an occasional boil are otherwise healthy.
When boils keep coming back, certain health factors may make them more likely. These include diabetes, obesity, smoking, malnutrition, anemia, iron deficiency, weakened immunity, and some skin conditions. However, recurrent boils alone do not prove that you have an iron or vitamin deficiency.
Repeated boils can also be related to carrying staph bacteria on the skin or in the nose, including MRSA, or to bacteria spreading between household members. Avoid squeezing or popping a boil, and do not share towels, razors, or other personal items that touch the skin.
See a doctor or dermatologist if boils keep returning, appear in clusters, are on the face, do not improve, or occur with fever, chills, or spreading redness. Avoid taking iron, high-dose vitamins, or antibiotics on your own, since treatment should depend on the underlying cause.