Sodium deficiency can cause swelling of the legs and feet. Sodium has an important role in maintaining the osmotic pressure of the crystals in the body, and there is a deficiency of sodium needed in the body. If there is a serious deficiency of sodium in the body, you may suffer from hyponatremia, which may cause the osmotic pressure of the plasma to abnormally decrease, and the water in the body may infiltrate from the blood vessels into the interstitial spaces of the skin, which may lead to the body to have edema. In addition, when there is a lack of sodium in the volume, there may also be dizziness, fatigue, nausea, vomiting, decreased urine output, etc. In severe cases, there may also be inflammation of the nervous system, such as cold expression and rigidity, and even the phenomenon of shock. In the diet can be appropriate to increase the content of salt as well as can drink light salt water, need to go to the hospital in time for relevant examinations, under the guidance of a professional doctor for treatment, to avoid aggravation of the condition, the impact on the body’s health.