Protein is an essential macronutrient involved in maintaining and improving numerous bodily functions. It supports muscle growth, repair, and strength, particularly when combined with resistance training, and contributes to muscle preservation in aging populations.
Protein deficiency can manifest in several ways, ranging from muscle wasting and persistent fatigue to more visible signs like hair thinning, fragile nails, and skin that heals slowly. Fluid retention, known as edema, may occur, often causing swelling in the legs, feet, or hands. In children, insufficient protein intake can lead to stunted growth and developmental delays. A weakened immune system, with increased susceptibility to infections, is also common. Additionally, protein deficiency can result in mood changes, irritability, and persistent food cravings. In more severe cases, it can lead to conditions such as kwashiorkor, marked by severe malnutrition and edema.