Which of the following nutrients plays a crucial role in immune function for athletes?

The correct choice highlights the significance of vitamins A, C, D, and minerals such as zinc and selenium in supporting immune function, particularly for athletes. These nutrients contribute to various aspects of the immune system.

Vitamin A is essential for maintaining skin and mucosal barriers, which serve as first lines of defense against pathogens. Vitamin C acts as an antioxidant, protecting immune cells from oxidative stress and helping to regenerate other antioxidants in the body. Vitamin D plays a role in modulating the immune response and may help reduce the risk of respiratory infections. Zinc and selenium are crucial for the proper functioning of immune cells, influencing their development and action.

Athletes often experience physical stress from training and competition, which can lead to a temporary suppression of the immune system. Adequate intake of these nutrients can help bolster immune defenses and enhance recovery, making them vital for maintaining health and performance.

The other options do not emphasize the essential nutrients that directly support immune system function. Sugar and saturated fats can potentially hinder overall health and immune response, carbohydrates are central to energy production but do not inherently support immune function, and while protein is critical for tissue repair and growth, it does not alone provide the comprehensive support needed for the immune system.