For leg cramps that occur in 12-year-old boys, this condition is mostly caused by calcium deficiency. Because 12-year-old boys, is in the stage of growth and development, if in the growth and development period, did not timely supplement calcium, which will lead to the body lack of calcium, thus causing leg muscle spasms caused by cramps. So after this situation, you can usually eat more calcium-containing foods, such as shrimp, soy products, dairy products, lean meat and fresh fruits and vegetables and other foods to promote the absorption of calcium. And you can eat more egg yolks, animal liver and other foods to promote the absorption of vitamin D, can be very good to promote the absorption of calcium. Calcium and vitamin D can be taken orally, which is also good for the recovery of leg cramps.