Certified Dietary Manager (CDM) Practice Exam 2025 – All-in-One Guide to Exam Success!

Vitamin A is essential for maintaining healthy vision as it plays a critical role in the formation of rhodopsin, a protein in the eyes that allows for vision in low-light conditions. Besides its contribution to vision, Vitamin A is also vital for immune function. It helps maintain the integrity of mucosal surfaces and regulates the immune response, making it an important nutrient for protecting against infections.

Vitamin B12, while important for nerve function and the production of DNA and red blood cells, does not have a direct role in vision or immune function. Vitamin C is known for its antioxidant properties and is important for skin health, collagen production, and immune support but does not play a key role in vision. Vitamin D is crucial for calcium absorption and bone health but does not significantly affect vision or immune function in the same way that Vitamin A does. Thus, Vitamin A stands out as the nutrient that has a direct impact on both vision and immune health.