Eat Right Practice Exam 2025 – The Comprehensive All-in-One Guide to Master Your Exam!

Vitamin A is essential for both vision and immune function, making it a critical nutrient in maintaining overall health. It plays a vital role in the formation of rhodopsin, a protein in the eyes that allows for vision in low-light conditions. Without adequate vitamin A, vision problems, particularly night blindness, can occur.

In terms of immune function, vitamin A is crucial for maintaining the integrity and function of mucosal surfaces in the body, including those of the respiratory and gastrointestinal tracts. These surfaces are the body's first line of defense against pathogens, and adequate levels of vitamin A help support their health.

While other vitamins listed also contribute to general health, they do not specifically fulfill the dual role of being directly linked to vision and immune function as effectively as vitamin A. Vitamin B is involved in energy metabolism but is not specifically tied to these functions. Vitamin C is well-known for its antioxidant properties and its support of the immune system, but it does not play a direct role in vision. Similarly, vitamin E is primarily an antioxidant and is involved in protecting cell membranes, but it does not have the same direct impact on vision as vitamin A does.