Vitamin B1 (Thiamine) Benefits, Food Sources, RDI, Deficiency & Side Effects

Photo by Jonathan Pielmayer on Unsplash

Thiamine, also known as thiamin or vitamin B1, is a vitamin found in food and used as a dietary supplement. It plays a critical role in ensuring a healthy nervous system and enhancing the cardiovascular functioning of the body. Vitamin B1 is one of the 8 water-soluble vitamins present in the B complex group and primarily helps in the conversion of carbs into glucose, which is then used to generate energy for performing various physical functions. Moreover, the vitamin is also needed to break down fats and proteins. Vitamin B1 is incredibly important and provides a host of benefits that can boost wellness and overall health.

Health Benefits of Vitamin B1 (Thiamine)

• Prevents Heart Diseases

This vitamin helps in the production of the neurotransmitter acetylcholine, which is used to relay messages between the nerves and muscles and to ensure proper cardiac function. Vitamin B1 deficiency can, therefore, result in irregular cardiac functions. When given vitamin B1 intravenously for seven days, people suffering from congestive heart failure showed considerable improvements in their echocardiograms, and this proves that it can prevent heart disease.

• Boosts Immunity

Thiamine helps to maintain the muscle tone along the walls of the digestive tract, where much of the immune system is actually located. Digestive health is important for thiamine absorption because a healthy digestive tract allows your body to extract nutrients from food better, which are used to boost immunity and defend you from becoming sick. Thiamine helps in the secretion of hydrochloric acid, which is essential for the complete digestion of food particles and absorption of nutrients.

• Offers Powerful Anti-Aging Qualities

Thiamine acts as a potent antioxidant, which helps safeguard your body against aging signs such as age spots, wrinkles, and other similar conditions that normally impact the organs.

• Metabolism

Some enzymes in your body cannot operate alone, and thiamine, either in the form of thiamin pyrophosphate or thiamin pyrophosphokinase, helps these enzymes function. Most notably, thiamine interacts with the coenzymes related to your cells’ mitochondria, which controls how your body converts food into energy. Accordingly, these coenzyme relations directly impact how you metabolize your food, particularly carbohydrates.

• Keeps Nerve Damage at Bay

One of the biggest vitamin B1 benefits is that it prevents nerve damage. If you are deficient in thiamine, you are greatly at risk for developing nerve damage. Nerve damage is life-interrupting and serious. Your body needs thiamine in order to oxidize consumed sugar through a process known as pyruvate dehydrogenase. If you are not getting enough energy through the consumption and digestion of food, your nervous system will become damaged. Nerve cells need vitamin B1 to help protect the myelin sheath (a thin layer of coating that shields the nerve cell). If the myelin sheath is damaged and the nerve cell underneath gets destroyed, a loss of memory, movement, and learning abilities can result.

• Thiamine May Lower Risk of Cataracts

Recent studies suggest that it may lower the risk of developing cataracts. These studies show that people who ingest plenty of protein along with vitamins A, B1, B2, and B3 (or niacin) in their diet are less likely to develop cataracts. Getting enough vitamins C, E, and B-complex vitamins further protect the lens of the eye.

Vitamin B1 (thiamine, thiamin) Recommended Dietary Intake (RDI)

Daily needs for thiamine are based on the amount of calories taken in each day. The recommended dietary intake (RDI) for Vitamin B1 is 1.1 mg per day for adult males and 0.8 mg per day for adult females, although women that are pregnant require an additional 0.2 mg per day and those that are lactating require an additional 0.4 mg. Dosages for infants and children should be much smaller and follow a pediatrician’s recommendation.

Food Sources of Vitamin B1



Thiamin (mg)

Lentils (cooked, boiled)

½ cup


Green peas (cooked, boiled

1 cup


Long-grain, brown rice (cooked)

1 cup


Long-grain, white rice, enriched (cooked)

1 cup


Long-grain, white rice, unenriched (cooked)

1 cup


Whole-wheat bread

1 slice


White bread (enriched)

1 slice


Fortified breakfast cereal (wheat, puffed)

1 cup


Wheat germ breakfast cereal (toasted, plain)

1 cup


Pork, lean (loin, tenderloin, cooked, roasted)

3 ounces*



1 ounce


Spinach (cooked, boiled)

½ cup



1 fruit



½ fruit



1 cup


Egg (cooked, hard-boiled)

1 large



Tea and coffee contain tannins, chemicals that may interact with thiamin, making it harder to absorb. Some of the chemicals in raw shellfish and fish can destroy thiamin, potentially leading to a deficiency if eaten in large quantities. Cooking destroys these chemicals, but it destroys thiamin too.

Symptoms of Vitamin B1 Deficiency

The symptoms of B1 deficiency are many and typically are related to the nervous, muscular and gastrointestinal systems. According to a review published by the journal Congestive Heart Failure, symptoms include depression, emotional instability, uncooperative behavior, fearfulness, agitation, weakness, dizziness, insomnia, memory loss, pain sensitivity, peripheral neuropathy, sonophobia, backache, muscular atrophy, myalgia, nausea, vomiting, and constipation.

Side Effects

Evidence does not confirm any harm from too much vitamin B1, but the U.S. Food and Drug Administration (FDA) warns on the use of supplements. They urge people to check with their healthcare provider before using supplements with or as a substitute for foods, and they call on the public to seek a physician’s advice on how to improve their health, rather than self-diagnosing.

Sources & References:

Healthy Food MasterVitamins and Mineralsanti-aging,B vitamins,healthy eyesight,heart,immune system,metabolism,nerve damage,vitamin b1
Photo by Jonathan Pielmayer on Unsplash Thiamine, also known as thiamin or vitamin B1, is a vitamin found in food and used as a dietary supplement. It plays a critical role in ensuring a healthy nervous system and enhancing the cardiovascular functioning of the body. Vitamin B1 is one of the 8 water-soluble...
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