Yes, a vitamin D deficiency can cause muscle weakness.
More Info: Recent studies have demonstrated that both adults and children with muscle weakness and pain may be suffering from a vitamin D deficiency. A series of studies involving children, men, women, and elderly patients, that presented with muscle weakness and pain, found that those given supplementation to restore the body's vitamin D levels were markedly improved over those given different supplementation or those given a placebo.
How Much Vitamin D Does the Body Need?
The amount of Vitamin D the body needs is dependent on the age of the individual taking it. For individuals aged one day to 50 years, the standard recommendation is 200 IU, or international units. From age 50 to 70 years, the recommended dose is 400 IUs a day. For individuals older than 70, 600 IU is the recommendation. Sources of vitamin D include natural sunlight, and vitamin supplements.
What Are Several Conditions That Cause Muscle Weakness?
Several conditions cause muscle weakness. A deficiency of an essential vitamin, mineral or other dietary need can lead to muscle weakness and fatigue. For example, a lack of vitamin D or potassium can both cause weak muscles. Your doctor can check for deficiencies with a simple blood test. A blood test can also find other potential causes for muscle weakness, including thyroid problems, Guillain-Barré syndrome and Myasthenia gravis. See a doctor if weakness is persistent. Sudden or severe muscle weakness can indicate a major problem, such as a stroke, and medical attention should be sought immediately.