Which nutrient deficiency is most common in older adults due to decreased absorption and intake?

• A. Vitamin D deficiency
• B. Vitamin C deficiency
• C. Vitamin B12 deficiency
• D. Iron deficiency

Answer: (C)

As people age, changes in the digestive system and typical intake patterns make it harder to get certain nutrients. Vitamin B12 relies on intrinsic factor produced in the stomach to be absorbed in the small intestine. Aging can lead to stomach lining thinning and less intrinsic factor, so B12 absorption drops. At the same time, older adults may eat less animal foods that provide B12, further reducing intake. The combination of poorer absorption and lower intake makes vitamin B12 deficiency the most common among older adults.

Other nutrients may be deficient for different reasons: vitamin D deficiency is common due to less skin synthesis and less sun exposure and intake, not primarily absorption issues; iron deficiency is often from blood loss or insufficient intake rather than aging-related absorption, and vitamin C deficiency is relatively rare.