Decreased intestinal absorption with aging is particularly noted for which nutrient?

Decreased intestinal absorption with aging is particularly noted for vitamin B12. As individuals age, various physiological changes occur in the gastrointestinal tract, including decreased production of hydrochloric acid in the stomach and alterations in overall gut motility. These changes can impact the absorption of several nutrients, but vitamin B12 is particularly affected.

Vitamin B12 requires the presence of intrinsic factor, a protein produced in the stomach, for its absorption in the small intestine. Aging can lead to atrophic gastritis, which reduces intrinsic factor production, thereby impairing vitamin B12 absorption. This deficiency can result in various health issues, including anemia and neurological problems.

While other nutrients also experience changes in absorption levels with aging, such as a decrease in the absorption of certain minerals and vitamins, vitamin B12 stands out due to the specific mechanism of its absorption being affected by the age-related changes in the stomach and intestines.