Thiamin (Vitamin B1): Why it’s important and where to find it

Thiamin (or thiamine), also known as Vitamin B1, is an essential nutrient and one of the many water soluble vitamins required for healthy living. The water soluble vitamins are those that may be dissolved in water. Only a small amount of thiamin is stored in the liver, so it must be consumed daily in the diet to provide the body with enough nutrient to support regular bodily functions.

Thiamin plays an important role in energy metabolism and helps the body break down carbohydrates, fats, and protein for energy use. Without sufficient thiamin in the diet, these metabolic processes start to break down, resulting in improper nerve function.

There are a few well-known diseases associated with thiamin deficiency including Wernicke-Korsakoff syndrome, which results in confusion, loss of muscle coordination, and issues with the peripheral nervous system that extends from the spinal cord. Beriberi is another disease associated with thiamin deficiency which also causes nervous system issues in addition to congestive heart failure and edema, or swelling, of the lower limbs. A mild thiamin deficiency may result in confusion, memory loss, and muscle weakness.

Thiamin deficiency is rare in most developed countries, but there are a few risk factors that may increase the risk of a deficiency including alcohol abuse, use of diuretics, HIV/AIDS, or diseases that reduce absorption of nutrients through the gut including celiac disease or bariatric surgery. The primary causes of deficiency in these conditions include increased urine output, liver disease, and poor nutrient absorption through the gut.

The recommended dietary allowance (RDA) for thiamin varies based on age, gender, and other health factors. For adult men, the recommendation is 1.2 mg per day, and for adult women the recommendation is 1.1 mg per day, but that recommendation increases to 1.4 mg per day for pregnant and lactating women.

There have been no adverse effects seen with excessive intake of thiamin. Because it is water soluble and processed by the liver and kidneys, any excess amount that the body doesn’t need is filtered out through urine.

Thiamin is found in a variety of foods, including meat like pork, fish, beef, and poultry, as well as whole grains, nuts and seeds, beans and lentils, and green peas.

There are some foods that may reduce the amount of thiamin absorbed by the body, such as tea, shellfish and raw fish, as these foods contain an enzyme called thiaminase that deactivates thiamin. Vitamin C helps prevent the action of thiaminase, so tea taken with lemon may help prevent the breakdown of thiamin to ensure sufficient absorption by the body.

Food processing may also break down thiamin and reduce the amount absorbed by the body. Because thiamin is water soluble, cooking or soaking food in water will cause the thiamin content of the food to leach into the water. If the water is thrown out, so is the thiamin nutrient. Cooking with high heat or for long durations will also break down thiamin. Thiamin is also removed through the refining process of rice and other whole grains, which removes the outer layer of the grain where most of the thiamin is stored. Rice and bread is often enriched with thiamin to add this nutrient back after the refining process.

Thiamin is an essential nutrient to ensure proper bodily function, particularly of the nervous system. Eating a balanced diet of whole grains, nuts and seeds, meat, and vegetables will ensure sufficient thiamin content to support basic functions.