Protein deficiency can lead to low immunity, edema, malnutrition, and indigestion. 1. Low immunity: Antibodies in the human body are mostly composed of proteins. When protein is lacking, the synthesis of antibodies in the human body is insufficient, leading to low autoimmunity and easy infection. 2. Edema: generally albumin can maintain the osmotic pressure of the body, protein deficiency will lead to a decrease in colloid osmotic pressure, resulting in fluid accumulation between tissues manifested as edema. 3. Malnutrition: Protein is involved in the composition of the body’s muscles and hair, etc., when protein deficiency will lead to muscle atrophy, hair loss, and so on. 4. Indigestion: Protein is also involved in the formation of some of the body’s digestive enzymes, a lack of protein can also lead to indigestion. Lack of protein or the occurrence of the above symptoms, in strengthening the nutrition at the same time, should be timely consultation, under the guidance of the doctor as soon as possible to correct.