The MedlinePlus website lists 14 different potential causes of hand cramps. No one factor appears to definitely trigger cramps, so isolating the cause is hard. However, two particular vitamin deficiencies may play a role. The main vitamin deficiency associated with cramps in the hand and elsewhere is a lack of vitamin D. Vitamin B6 deficiency may also have an effect. Other causes include a lack of minerals or general dehydration.
Any muscle in the body can experience cramps. However, cramps tend to occur more in the legs, arms, and sometimes the feet and hands. Overuse and dehydration often cause cramps in athletes. Spending a long time at the computer using a mouse or keyboard may also trigger hand cramps. The cramps themselves are a very fast twitching spasm inside the muscle. This sends pain impulses to the brain until the twitching stops.
Without vitamin D, your body wouldn't be able to use calcium. As all children know, calcium that you find in milk and other dairy products helps build healthy teeth and bones. Your body only makes vitamin D through the skin, involving a reaction with sunlight. Dietary sources include fish and dairy, but supplements may be required for a serious deficiency. According to Robert W. Neel, M.D., a vitamin D deficiency can lead to arm or hand cramps.
Vitamin B6, or pyridoxine, may help suppress muscle cramping. A B6 deficiency could indirectly lead to more hand cramps. A 1998 study published in "Neuromuscular Disorder" showed that patients suffering from McArdle disease who stopped taking B6 supplements for 10 weeks experienced an increase in muscle cramping. You can get B6 from foods such as fish, eggs, wheat-germ products, grains and walnuts.
Though different from vitamins in a nutritional sense, it's worth noting that a lack of certain minerals seems to trigger cramping. A diet very low in potassium, sodium, magnesium and possibly calcium may make your hands cramp, according to Health Services at Columbia University. If you get regular exercise, you lose minerals through sweat. If you don't replace them, you could run into problems. Your muscles need these minerals, known as electrolytes, to properly contract and function. Without them, they tend toward cramping.