The most obvious symptoms of calcium deficiency in adults include loose teeth, osteoporosis and muscle cramps. 1. Loose teeth: Calcium is an important component of human teeth, and a very serious decline in calcium content will reduce the firmness of the teeth and loose teeth will occur. 2. Osteoporosis: When the calcium in human bones is not absorbed enough or consumed too much, it will easily cause osteoporosis, which makes the bone density decrease and the brittleness of the bone increase, thus increasing the risk of fracture. 3. Muscle cramps: Calcium can maintain neuromuscular excitability, calcium deficiency in adults will cause abnormal neuromuscular excitability, muscle spasm phenomenon, which is often referred to as “leg cramps”. In addition to the above, calcium deficiency in adults may also lead to other discomforts, such as easy to back pain, etc. If the above symptoms, it is recommended to go to the hospital for examination, and follow the doctor’s instructions in time for targeted treatment, so as not to delay the course of the disease.