Memory loss may be indicative of a deficiency in which of the following vitamins?

Thiamin, also known as vitamin B1, plays a critical role in glucose metabolism and the functioning of the nervous system. A deficiency in thiamin can lead to neurological problems, including memory loss. This is particularly evident in conditions such as Wernicke-Korsakoff syndrome, which is associated with chronic alcoholism and results from thiamin deficiency. Symptoms include confusion, ataxia, and significant memory issues.

In contrast, while deficiencies in vitamins A, D, and riboflavin can lead to various health issues, they are less specifically associated with memory impairment. Vitamin A is crucial for vision and immune function, vitamin D is essential for bone health and various metabolic processes, and riboflavin is important for energy production, but none are strongly correlated with memory loss as thiamin is. Thus, thiamin is the vitamin most directly linked to issues with memory when there is a deficiency.