What is one potential symptom of a protein deficiency?

Muscle wasting is a potential symptom of protein deficiency because proteins play a crucial role in the maintenance and repair of body tissues, including muscles. When there is an inadequate intake of protein, the body may start to break down muscle tissue to meet its needs for essential amino acids, leading to muscle wasting. This condition can result in decreased strength and functional capacity, reflecting the body's inability to adequately repair or build muscle tissue due to insufficient protein availability.

In contrast, glossy hair and heightened energy levels are typically associated with adequate nutrition, including sufficient protein intake. Protein is essential for hair structure, and a lack of it can lead to hair thinning or dullness rather than glossiness. Improved immune function is also reliant on adequate protein, as proteins are involved in the production of antibodies and other immune system components. A deficiency can compromise immune response rather than improve it. Thus, muscle wasting stands out as a clear symptom directly linked to protein deficiency.