Vitamin D toxicity, or hypervitaminosis D, is caused by high blood calcium (hypercalcaemia). Early symptoms can include nausea, vomiting, constipation, abdominal pain and loss of appetite. Neurological effects such as confusion, headaches and weakness may also occur. In severe cases, patients can slip into stupor or coma. As reported by medical reviews, kidney issues such as excessive thirst, frequent urination and kidney stones are common, along with bone pain, muscle weakness and irregular heart rhythms.
