Osteoporosis is a complication of untreated celiac disease. The small intestine is responsible for absorbing important nutrients, such as calcium. Calcium is essential for building and maintaining healthy bones. Even people with celiac disease who consume enough calcium are often deficient in this nutrient.Less commonly, people with celiac disease have joint pain, osteoporosis or osteopenia (low bone mass before osteoporosis), anemia (from impaired iron absorption), leg numbness (from nerve damage), muscle cramps (from impaired calcium absorption), aphthous ulcers (sores in the mouth from vitamin deficiency), seizures,People recently diagnosed with celiac disease are commonly deficient in fiber, iron, calcium, magnesium, zinc, folate, niacin, riboflavin, vitamin B12, and vitamin D, as well as in calories and protein. Deficiencies in copper and vitamin B6 are also possible, but less common.