Final answer:
Thiamine deficiency leads to harmful changes in brain function because thiamine is critical for carbohydrate utilization and brain cell metabolism. Without adequate thiamine, there is an accumulation of pyruvate and lactate in the brain, impairing normal neuronal function.
Step-by-step explanation:
Thiamine, also known as Vitamin B1, is essential for normal brain metabolism and plays a crucial role in the utilization of carbohydrates in the body. The clinical form of thiamine deficiency is known as Beri-Beri, which is characterized by neurological symptoms such as loss of reflexes, anxiety, and mental confusion. This is mainly because thiamine, specifically in its active coenzyme form thiamine pyrophosphate (TPP), is critical for oxidative decarboxylation and transketolation reactions that are essential for brain cell function. Deficiency leads to the accumulation of pyruvate and lactate in the cells, particularly affecting the brain due to its inability to retain thiamine and increased permeability of the blood-brain barrier to pyruvate in cases of deficiency.
Sources of thiamine include rice bran, wheat bran, whole grains, nuts, beans, fish, meat, and milk. Since the body cannot store thiamine for long and the brain cannot retain it at all, it is necessary to include thiamine-rich foods regularly in the diet to maintain proper brain and neurological function.