Vitamin B1 (Thiamine)

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What is Vitamin B1?

Also known as thiamine, vitamin B1 is a water-soluble compound, one of eight vitamins in the vitamin B group. The common denominator of all compounds in this group is their primary role, which is the metabolism of fats, proteins, and carbohydrates. Without them, carbohydrates couldn't be processed into energy to fuel the body.

B-complex vitamins are sometimes called anti-stress because they prevent stress by supporting the immune system and the body's resistance to stressful conditions. If you are not familiar with B vitamins, here is a list of all of them and their alternative names:

Compounds from this group assist certain enzymes in their work. The essential roles of these enzymes include releasing energy from carbohydrates and fat, transporting energy and oxygen, and breaking down amino acids.

Roles of Vitamin B1

Because thiamin affects the work of enzymes, it is linked to many bodily functions. It also helps prevent health complications caused by impaired metabolism. Regularly consuming this nutrient is necessary because the human body cannot produce it. Below are the health benefits linked to proper daily vitamin B levels. See which ones have been already backed by science and which require more research to confirm them:

Beneficial for the Nervous System

Daily thiamine consumption supports a healthy nervous system thanks to the optimal metabolism, in which it plays a significant role. The process of turning carbohydrates into energy requires vitamin B1. Various body parts, including the brain and nervous system, use fuel obtained from this process to continue their tasks.

Thiamine is also involved in developing myelin sheaths, a protective layer covering nerves. Myelin ensures that electrical impulses quickly activate between the nerve cells. Damaged myelinTrusted Source slows down this process and leads to neurological conditions like multiple sclerosis.

Supports the Immune System

Another system supported by thiamine is the immune system. It is beneficial for proper muscle tone situated along the digestive tract walls. In this indirect way, it plays a role in digestive health that is essential for fighting off disease and improving the ability of the whole body to withstand stress.

Boosts Cognitive Functions

Thiamine is also linked to better focus, memory, and reaction timeTrusted Source. Vitamin B1 deficiency has been proven to cause cognitive issues such as memory loss and problems with learning and retaining information.

In one study, vitamin b1 contributed to better reaction time and clear-headedness in participants who took 50 mg of the vitamin supplement daily for two months compared to the placebo group.

Support Heart Health

Vitamin B1 takes part in the synthesis of yet one more essential substance in the body – a neurotransmitter known as acetylcholineTrusted Source. It plays a vital role in brain functions and in relaying messages between muscles and nerves, including the heart as one of such muscles.

Moreover, according to recent studies, thiamine may aid the body in overcoming heart diseaseTrusted Source, as it promotes healthy ventricular function.

Promotes Positive Mood

Thiamine is sometimes referred to as an anti-stress vitamin for a reason. It can boost mood and increase overall energy levels. Fatigue is a significant factor that comes into play in developing depression, anxiety, or bad mood. Thiamine can raise your motivation and ability to overcome stress by warding off tiredness. 

Best Food Sources

Thiamin is naturally found in meat, fish, whole grains, and nuts. Some foods, such as infant formulas, cereals, and bread, are reinforced with vitamin B1. The table below shows some of the best food sources containing high levels of this nutrient:

FoodServing sizeThiamine amount
Breakfast cereals, fortified1 bowl1.2 mg
Pork chop, bone-in, broiled3 ounces 0.4 mg
Trout, cooked, dry heat3 ounces 0.4 mg
Lean Pork Chops100 grams0.7 mg
Fish (Salmon) 100 grams0.3 mg
Flax Seeds100 grams1.6 mg
Navy Beans100 grams0.2 mg
Black beans, boiled½ cup0.4 mg
Firm Tofu100 grams0.2 mg
Brown Rice 100 grams0.2 mg
Acorn Squash100 grams0.2 mg
Mussels 100 grams0.2 mg
Asparagus100 grams0.3 mg
Egg noodles, enriched 1 cup0.5 mg
Green Peas100 grams0.3 mg
Vitamin B1 (Thiamine): Food, Benefits, and Deficiency

Recommended Daily Intake

So, how much vitamin B1 does your body need? The recommended dietary allowance (RDA) depends on age, sex, and whether you are pregnant or breastfeeding. See the table below for the recommended values of thiamin:

0–6 months0.2 mg0.2 mg
7–12 months0.3 mg0.3 mg
1–3 years0.5 mg0.5 mg
4–8 years 0.6 mg0.6 mg
9–13 years0.9 mg0.9 mg
4–18 years1.2 mg 1.0 mg1.4 mg1.4 mg
19-50 years 1.2 mg1.1 mg1.4 mg1.4 mg
Older than 51 years 1.2 m1.1 mg

But what exactly is the Recommended Dietary Allowance? RDATrusted Source is a daily intake of a given nutrient for healthy people. The Food and Nutrition Board of the National Academies of Sciences, Engineering, and Medicine issues it. To establish a recommended amount, the board considers the safety and quality of a given nutrient. It ensures that its values are healthy and beneficial for healthy individuals.

What Causes Vitamin B1 Deficiency?

Thiamine deficiency very rarely occurs in developed countries. In the United States, most people meet its recommended daily amounts by consuming regular meals. Health issues caused by a lack of vitamin B1 usually apply to people with specific health issues. Here is a list of conditions that may put you at risk of vitamin B1 deficiency:

Pregnant and breastfeeding women require a higher intake of all B-complex vitamins, which puts them at a higher risk of developing deficiency.

Symptoms of Vitamin B1 Deficiency

Symptoms caused by low absorption of thiamine range from mild to severe and affect different body parts. Since vitamin B1 is stored in the body in small amounts and for a short period, symptoms may develop even within two weeks. Linking them to thiamin deficiency is not apparent, as they can mimic symptoms of other conditions. The most likely complications to occur include the following:

Because low levels of thiamine slow down metabolism, several organs are affected. The brain, heart, tissues, kidneys, liver, and skeletal muscles are all negatively impacted by insufficient concentration of this compound in the body.

Vitamin B1 (Thiamine): Food, Benefits, and Deficiency

Vitamin B1 Deficiency and Alcoholism

In developed countries, including the United States, thiamine deficiency is most frequently observed among people with alcoholism. This type of vitamin depletion is also known as Wernicke-Korsakoff syndromeTrusted Source and Korsakoff's amnesic syndrome.

Long-term misuse of alcoholic drinks leads to decreased absorption and reduced capability of the body cells to use thiamine. What is more, alcoholism is often associated with under-eating – alcoholics tend to skip meals or have inadequate diets due to satisfying their own needs by drinking large amounts of alcohol. This results in decreased consumption not only of vitamin B1 but also of many other nutrients, which is an additional factor in deficiency.

Wernicke-Korsakoff syndrome contributes to nerve damage, causing harm to:

Symptoms caused by Wernicke-Korsakoff syndrome include the following:

Most of the above symptoms can be treated and even reversed. The biggest challenge involves memory functions, which can be improved with time, but the damage may not be fully reversed. The treatment usually requires thiamine replacement, proper hydration, and a well-balanced, nutritious diet.

Vitamin B1 and Caffeine

Another interaction that is worth discussing is vitamin B1 and high caffeine intake. Certain food products may destroy thiamineTrusted Source. One of them is a substance found in drinks many people enjoy daily – caffeine. Whether it's tea, coffee, or energy drinks, all caffeinated drinks may decrease the absorption of thiamine in the small intestine. It happens because caffeine changes the chemical composition of thiamine, making it difficult to absorb. Fortunately, all tea and coffee enthusiasts are safe from this scenario if they drink it in moderation. Problems arise when a person consumes too much, causing caffeine toxicity.

In the United States, the RDA for coffee is 400 milligramsTrusted Source of caffeine daily, which is lower than the average amount consumed by an adult American (135 mg daily). It is a little less convenient for pregnant women who should not drink more than 2 cups of brewed coffee (200 mg) to prevent thiamine deficiency.

Vitamin B1 Toxicity

How much vitamin B1 is too much for the body to handle? Is it possible to overdose thiamin, like some vitamins and minerals? Well, it appears it is highly unlikely. As previously mentioned, the human body doesn't store thiamin for too long, making quick use of it. Moreover, in scenarios with too much thiamin, the body flushes out the excess amount through the urine within a few hours.

Confirmed severe cases of thiamine toxicity are very scarce, making it a very improbable scenario. Likely, toxicity occurs due to other underlying health conditions. Because of that, there is no established level of vitamin B1 toxicity.

Closing CComments

Vitamin B1 (thiamine) supports cognitive health, metabolism, and heart functions and prevents many health complications. It is a necessary nutrient that the body needs to obtain energy from carbohydrates.

Thiamine deficiency is very unlikely to happen in developed countries. However, if it occurs, for instance, due to a lousy diet or specific health problems, it can harm the body in numerous ways. 

Deficiency risk factors usually include alcohol misuse, anorexia, under-eating, and liver damage. Pregnant and breastfeeding teens and adult women are also more at risk due to the increased body demand for all vitamins from the B group.

The exciting fact about vitamin B1 is that it cannot be overdosed. It is quickly absorbed while the excess amount exits the body with the urine. Due to this reason, toxicity levels haven't been established. 


June 19, 2023
9 minutes read

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