Vitamin B1 (Thiamine) Test

Vitamin B1, also called thiamine, is an essential water-soluble vitamin that plays a vital role in turning the carbohydrates you eat into energy your cells can use. Once absorbed, your body converts vitamin B1 into its active form, thiamine pyrophosphate (TPP), which acts as a coenzyme in several critical metabolic pathways, including the Krebs cycle and the pentose phosphate pathway. These pathways generate energy, synthesize DNA and fatty acids, and keep your brain and nervous system functioning properly.

Because your body stores very little vitamin B1 and excretes any excess in urine, a steady intake is necessary. Vitamin B1 is found in foods like whole grains, pork, legumes, and fortified cereals. It is particularly vulnerable to destruction by heat, pH changes, and food processing, which means refined grains and processed foods tend to be poor sources unless fortified.

Vitamin B1 is essential for the health of the nervous system, and a deficiency can lead to two serious clinical syndromes: beriberi and Wernicke-Korsakoff syndrome. Beriberi exists in two forms: dry and wet. Dry beriberi primarily affects the nerves and causes peripheral neuropathy, muscle weakness, and coordination issues. Wet beriberi impacts the heart and circulatory system, leading to symptoms like rapid heart rate, leg swelling, and heart failure. Wernicke-Korsakoff syndrome is a neurological condition associated with chronic vitamin B1 deficiency, particularly in people with alcohol use disorder. The acute stage, Wernicke encephalopathy, includes confusion, eye movement problems, and difficulty walking. If untreated, it can progress to Korsakoff psychosis, marked by memory loss and hallucinations.

Other risk factors for deficiency include malnutrition, persistent vomiting, eating disorders, bariatric surgery, and long-term diuretic use. Even in Western countries, low-level vitamin B1 deficiency may be underdiagnosed, especially among hospitalized or elderly individuals. In infants, vitamin B1 deficiency can cause life-threatening cardiac symptoms and lasting neurological damage if not caught early.

Biochemically, vitamin B1 deficiency disrupts mitochondrial energy production, leading to lactic acid buildup and cell damage, especially in energy-demanding organs like the brain and heart. This can explain the wide range of symptoms, from fatigue and nerve pain to confusion and cardiac dysfunction.

Vitamin B1’s role in maintaining brain energy metabolism, nerve conduction, and heart function makes it indispensable for longevity and optimal health. It’s not just a deficiency vitamin; emerging evidence also links low vitamin B1 levels to depression, chronic fatigue, and even heart failure, suggesting that maintaining optimal, not just adequate, levels may support better healthspan outcomes.