Vitamin B1, also called thiamine, is one of eight B vitamins. It is a water-soluble vitamin, meaning it travels through the bloodstream and is not stored in large amounts by the body. With only small quantities kept in the liver, it must be consumed regularly through diet. What the body does not use is removed through urine.
The Role of Vitamin B1 in the Body
Thiamine’s primary function is to help the body convert carbohydrates from food into glucose, which cells use for energy. This process is important for the brain and nervous system, which have high energy demands. Thiamine acts as a cofactor, or a “helper molecule,” for several enzymes that are part of major metabolic pathways.
These enzymes are necessary for reactions that break down sugars and lipids to generate energy. Beyond energy production, thiamine is also involved in the proper function of nerves and muscles. It assists in the flow of electrolytes into and out of muscle and nerve cells, which is necessary for nerve signal conduction and muscle contraction.
Food Sources of Vitamin B1
A variety of common foods contain thiamine, making it accessible in a balanced diet. Whole grains and products fortified with thiamine, such as cereals, breads, and pasta, are significant sources. In the United States, about half of the thiamine intake comes from foods that naturally contain it, while the rest is from fortified products.
Certain proteins are also rich in this nutrient, with pork being a particularly good source. Other animal-based sources include fish like trout and tuna, as well as eggs. For those following plant-based diets, legumes like black beans and peas, along with various nuts and seeds, provide substantial amounts. Some vegetables and fruits, including asparagus and oranges, also contribute to daily intake.
Understanding Vitamin B1 Deficiency
A lack of sufficient thiamine can lead to health issues, with early symptoms often being nonspecific, such as fatigue and weakness. A severe deficiency can result in a condition known as beriberi. Beriberi can affect the cardiovascular system by causing an enlarged heart or the nervous system, leading to muscle loss and reduced sensation in the hands and feet.
In some populations, particularly individuals with chronic alcohol misuse, a severe thiamine deficiency can cause brain damage. Alcohol interferes with the body’s ability to absorb and store thiamine. This can lead to Wernicke-Korsakoff syndrome, a neurological disorder with two stages. The first, Wernicke’s encephalopathy, involves confusion and unsteadiness, while the second, Korsakoff syndrome, is characterized by memory loss and difficulty forming new memories. People with certain gastrointestinal conditions or poor nutrition are also at a higher risk.
Recommended Intake and Supplementation
The recommended dietary allowance for thiamine varies by age and sex. For adults 19 and older, the recommendation is 1.2 mg per day for men and 1.1 mg per day for women. These amounts increase for pregnancy and lactation to 1.4 mg daily. Most individuals can meet these requirements by consuming a balanced diet.
Supplements may be suggested by a healthcare provider for individuals who cannot get enough thiamine through food, such as those with risk factors for deficiency. Because thiamine is water-soluble, the body excretes what it doesn’t need, making toxicity from high intakes through food or supplements very rare. There is no established maximum daily dose known to cause negative side effects.