Low levels of vitamin D can cause muscle weakness and bone pain. The vitamin is stored in the liver where it is then metabolized. Because vitamin D is needed for bone formation and growth, deficiency decreases calcium absorption in the body and often leads to musculoskeletal pain. Individuals who have mild to moderate deficiency may experience muscle weakness, pain, numbness or tingling, and muscle cramps and twitching, also known as fasciculation. A study conducted at the University of Michigan Medical School found that hospital patients with unexplained muscle and skeletal pain were more likely to have vitamin D deficiency regardless of age. This led researchers to conclude that people with unexplained pain should be tested for vitamin D.
Leg pain is a common symptom of vitamin D deficiency. Osteomalacia is a condition, which refers to the softening of the bones. Although there may be no symptoms at first, over time, osteomalacia worsens, causing symptoms such as pain in the legs and lower spine, muscle weakness in the arms and legs, and decreased muscle tone. Causes for osteomalacia include inadequate dietary intake of vitamin D and not enough exposure to sunlight. The body needs vitamin D for strong bones, just as it needs to absorb adequate sunlight to produce vitamin D in the skin. Those at risk are individuals who spend little time out in the sunlight or live in smoggy areas or geographical regions where daylight hours are short during certain seasons of the year. Older individuals who are reside in long-term care facilities are at particular risk.
Deficiencies in vitamin D or the minerals calcium and magnesium can cause muscle twitching. Many times twitching occurs in the hands, legs and feet and is accompanied by numbness and tingling. These involuntary muscle twitches are small contractions that most often affect single muscles. Sometimes electrical impulses along nerve pathways begin to misfire unpredictably causing muscles at different locations in the body to contract and relax. While a person is unable to control the twitching, most times it is minor. Diet deficiencies are often responsible for these motor nerve fibers firing random impulses from the brain or spinal cord. Vitamin D plays a role in regulating cellular processes in the nervous system and muscle tissue. Tetany, another condition caused by a lack of calcium or low levels of magnesium, is characterized by involuntary muscle contractions.