Miss Universe Harnaaz Sandhu reveals struggle with celiac disease. What the condition is

Celiac disease can cause both weight gain and loss, according to Today’s Dietitan, a magazine for nutrition professionals.

The disorder can cause long-lasting digestive troubles, keeping the body from receiving all the nutrition that it requires, according to the United States' National Institute of Diabetes and Digestive and Kidney Diseases.

People with celiac disease need to cut out from their diets food containing gluten -- a protein naturally found in rye, wheat and barley. It also occurs in bread, pasta and  cereal.

According to England's National Health Service, celiac disease can cause long-term complications like anaemia and weakening of bones.

"Less common and more serious complications include some types of cancers, such as bowel cancer, and problems affecting pregnancy, such as your baby having a low birth weight," NHS adds.

There is no cure for celiac disease, but patients can keep their symptoms under control and prevent long-term complications by adhering to a gluten-free diet.