What is the main purpose of sebum in skin health?

The primary role of sebum is to lubricate and protect the skin. Sebum is an oily substance produced by the sebaceous glands, which helps to maintain the skin's moisture balance, preventing it from drying out. This natural oil creates a barrier on the skin's surface that protects against environmental factors such as bacteria, pollutants, and harsh weather conditions. By maintaining the skin's hydration level, sebum also plays a vital role in the overall health and elasticity of the skin, which can help prevent premature aging.

While sebum may have minor contributions to cooling, providing nutrients, and aiding in healing, those functions are not its main purposes. The cooling effect is mainly achieved through sweat, while nutrients are typically acquired through diet, and healing involves a range of biological processes beyond sebum alone. Thus, the correct answer highlights sebum's significant protective and lubricating functions, which are crucial for maintaining skin health.