National Physical Therapy Examination (NPTE) Practice Exam

How does intrinsic factor contribute to vitamin B12 absorption in older adults?

1. Enhances muscle growth

2. Facilitates absorption in the small intestine

3. Decreases calcium absorption

4. Neutralizes stomach acid

The correct answer is: Facilitates absorption in the small intestine

Intrinsic factor plays a crucial role in the absorption of vitamin B12 by binding to the vitamin in the gastrointestinal tract, specifically in the small intestine. In older adults, the production of intrinsic factor may decline, which can impact vitamin B12 absorption. However, when intrinsic factor is present, it enables vitamin B12 to be effectively absorbed in the terminal ileum of the small intestine. Vitamin B12 is essential for various bodily functions, including red blood cell formation and neurological health. Without intrinsic factor, vitamin B12 would not be efficiently absorbed, leading to potential deficiencies, especially in older individuals who may already be at risk. This underscores the importance of intrinsic factor in the process of vitamin B12 absorption, particularly in older adults who might face physiological changes affecting nutrient uptake. The other options do not pertain to the role of intrinsic factor in vitamin B12 absorption. For example, while muscle growth, calcium absorption, and neutralization of stomach acid are vital physiological processes, they do not directly relate to the mechanism by which intrinsic factor aids in the absorption of vitamin B12. Thus, the focus on its role in facilitating absorption in the small intestine underlines its significance in nutritional health.