Dietetic Technician Practice Test 2025 – All-in-One Guide to Exam Success!

Vitamin A is essential for vision and immune function due to its crucial role in the formation of rhodopsin, a protein in the retina that enables the eye to perceive light. This process is vital for night vision and overall visual acuity. Additionally, Vitamin A plays a significant part in maintaining the integrity and functioning of the immune system. It supports the development and differentiation of immune cells, enhancing the body's ability to fight off infections.

The other vitamins, while important in their own right, do not have the same direct impact on vision and immune function. Vitamin B12 is primarily involved in red blood cell formation and neurological function. Vitamin D is critical for calcium absorption and bone health, while Vitamin E serves as an antioxidant, protecting cells from oxidative damage. However, neither of these vitamins is directly linked to the specific functions of vision and immune support in the way that Vitamin A is.