Certified Personal Trainer (NSCA) Practice Exam 2025 – Complete Prep Guide

Vitamin D plays a crucial role in calcium absorption in the body. When vitamin D is present, it enhances the intestinal absorption of calcium from the foods we consume. This is essential for maintaining strong bones and overall skeletal health because calcium is a critical mineral for bone formation and maintenance. Without adequate levels of vitamin D, the body cannot efficiently absorb calcium, which can lead to deficiencies and related health issues such as osteoporosis.

Other vitamins listed, such as A, B12, and C, do not have a direct role in promoting calcium absorption. Vitamin A is important for vision and immune function, vitamin B12 is necessary for red blood cell formation and neurological function, and vitamin C is involved in collagen synthesis and antioxidant protection. However, none of them are essential for the process of absorbing calcium from the gut. Thus, vitamin D is recognized as the key vitamin necessary for this important physiological function.