What is the role of thiamine (Vitamin B1) in cognitive function?

From the Guidelines

Thiamine (Vitamin B1) plays a crucial role in cognitive function, and its deficiency can lead to severe cognitive impairment, making supplementation essential for individuals at risk, particularly those with malnutrition, poor oral intake, chronic alcohol consumption, and increased metabolic requirements. The brain requires thiamine to convert glucose into energy through the Krebs cycle, and without sufficient thiamine, neurons cannot produce the ATP needed for proper functioning 1. Thiamine also supports the production of acetylcholine, a neurotransmitter vital for memory and learning. Deficiency can lead to Wernicke-Korsakoff syndrome, characterized by confusion, memory problems, and cognitive impairment. Even mild deficiency can cause fatigue, irritability, and reduced concentration.

Key Points to Consider

• Thiamine deficiency is common in patients with malnutrition, poor oral intake, and chronic alcohol consumption, and can be prevented with supplementation 1
• The recommended dosage of thiamine varies, but IV thiamine 250 mg is required to manage encephalopathy in patients with chronic alcohol ingestion 1
• Thiamine supplementation is essential for preventing cognitive decline, especially in vulnerable populations, such as those with alcohol use disorder, malabsorption conditions, or poor nutrition 1
• Oral thiamine 200-300 mg daily or intravenous vitamin B preparation should be given immediately to people at risk of thiamine deficiency or with clinical suspicion of acute deficiency 1

Prevention and Treatment

• Maintaining adequate thiamine levels is crucial for preventing cognitive decline, especially in vulnerable populations
• Education on the potential risks of thiamine deficiency and the importance of initiating immediate treatment is essential for clinicians and patients 1
• Thiamine supplementation should be considered for individuals with prolonged vomiting, dysphagia, poor nutritional intake, inability to tolerate vitamin and mineral supplements, high alcohol intake, or fast weight loss 1

From the Research

Thiamine and Cognitive Function

• Thiamine (Vitamin B1) plays a crucial role in maintaining cognitive function, with deficiencies often associated with cognitive impairments in patients with Alcohol Use Disorder (AUD) 2.
• Studies have shown that thiamine supplementation can lead to improvements in cognitive function in AUD patients, even in the absence of thiamine deficiency 2, 3.
• The cognitive domains particularly affected by thiamine deficiency include visuospatial/executive ability, abstraction, attention, verbal fluency, and memory scores, notably delayed memory 2.

Mechanisms of Thiamine Deficiency

• Thiamine deficiency can lead to a range of neurological and psychiatric symptoms, including confusion, reduced memory, and sleep disturbances, due to its essential role in energy metabolism and biosynthesis of nucleic acids 4.
• The brain is highly vulnerable to thiamine deficiency, particularly during rapid growth periods, and thiamine-dependent enzymes are involved in antioxidant machinery and energy production 4, 5.
• Thiamine deficiency has been linked to various neurodegenerative diseases, including Alzheimer's and Parkinson's diseases, independent of patient malnutrition 5.

Thiamine Supplementation and Neuroprotection

• Thiamine precursors with higher bioavailability, such as benfotiamine and dibenzoylthiamine, have been shown to have neuroprotective effects and improve cognitive outcome in patients with mild Alzheimer's disease 6.
• Thiamine supplementation has been associated with improvements in cognitive function in patients with AUD, and may be a sufficient medication to prevent cognitive decline in AUD patients 3.
• The identification of active neuroprotective derivatives and the clarification of their mechanism of action open promising perspectives in the field of neurodegenerative, neurodevelopmental, and psychiatric conditions 6.