Which vitamin's absorption can be hindered by antacids?

Vitamin B-12 absorption can be hindered by antacids due to the vitamin's dependence on an acidic environment for adequate absorption in the gastrointestinal tract. Specifically, vitamin B-12 is typically bound to proteins in food and requires a sufficient level of stomach acid to be released from these proteins. The acidic environment also aids in the proper functioning of intrinsic factor, a protein secreted by the stomach that is crucial for B-12 absorption in the small intestine.

When antacids are used, they increase the pH level in the stomach, making it less acidic. This can interfere with the release of vitamin B-12 from food sources and diminish its subsequent absorption through the intestinal lining. Reduced absorption of this vitamin can lead to deficiencies, which is particularly concerning for older adults who may already be at risk due to decreased stomach acid production.

In contrast, while vitamins A, K, and E are also important for health, their absorption is less directly impacted by changes in stomach acidity than that of vitamin B-12.