Can Vitamin D Deficiency Cause A Seizure?

Vitamin D is found in two relevant forms in nature. Vitamin D2, or ergocalciferol, is produced by plants and mushrooms. Vitamin D3, or cholecalciferol, is found in fatty fish, such as mackerel, salmon and tuna and in dairy products and other fortified foods. Vitamin D3 is also the only vitamin that can be naturally produced in your body. Whenever you are exposed to sunlight, vitamin D3 is synthesized in your skin, using cholesterol as a precursor. Vitamin D deficiency causes a variety of health problems, and severe deficiency can lead to seizures.

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According to an April 2011 review in "Discovery Medicine," nearly every tissue in your body possesses vitamin D receptors, or VDRs. Through stimulation of VDRs in bone cells, vitamin D plays a vital part in the mineralization of your skeleton. The interaction of vitamin D with tissue VDRs plays a role in immunity, growth regulation, cardiovascular health, cancer development and mineral balance. Vitamin D's participation in calcium metabolism is critical for normal nerve, muscle and cardiovascular function.

Deficiency

If you get too little sunlight to produce sufficient amounts of vitamin D, you must acquire this nutrient from dietary sources. The average adult needs 600 IU daily to avoid deficiency, and more--perhaps 2,000 IU daily--is needed for optimal health, according to Dr. Reinhold Vieth at Mount Sinai Hospital in Toronto. Vitamin D deficiency in children leads to a condition called rickets, which is characterized by delayed development, poor bone mineralization, long bone deformities and scoliosis. In children and adults, deficiency can cause bone pain, muscle aches and weakness. Severe, prolonged vitamin D deficiency leads to "rachitic tetany," which manifests as numbness in the face, tongue and extremities, muscle spasms and, possibly, seizures.

Compensation

Your body goes to great lengths to maintain blood calcium levels within a relatively narrow range. Your parathyroid glands, which are nestled behind the thyroid gland in your neck, produce parathyroid hormone, or PTH. Whenever your vitamin D or calcium levels begin to fall, your parathyroid glands secrete more PTH, which increases absorption of calcium from your intestine and kidneys and stimulates the removal of calcium from your bones. This compensatory mechanism has its limits, however, and--in the face of continued vitamin D deficiency--calcium levels eventually fall. If left untreated, rachitic tetany ensues.

Considerations

Severe vitamin D deficiency, characterized by rachitic tetany and seizures, is rarely seen in developed countries, due to the availability of fortified foods. However, according to "The Merck Manual of Diagnosis and Therapy," milder forms of vitamin D deficiency can result from inadequate sun exposure, poor dietary intake, reduced absorption or genetic anomalies that cause vitamin D resistance. Such "subclinical" vitamin D deficiency might be evidenced by immune disorders, infections or other problems which are not immediately recognized as a deficiency of vitamin D.

Recommendations

In 2011, as scientists learn more about vitamin D's diverse activities in the human body, many experts are advising more sun exposure to help alleviate subclinical vitamin D deficiencies, and they are calling for changes in dietary guidelines to reflect a need for higher doses. Current recommended dietary allowances--the dosages required to avoid deficiency--range from 400 IU for infants to 800 IU for adults over the age of 70.