Thiamine: What It Is and 6 Health Benefits

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Getting enough thiamine in your diet can protect your heart, brain and nervous system

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Thiamine or vitamin B1 and potatoe, olive and orange slice

Vitamin B1 (thiamine or thiamin) is one of eight B vitamins. It’s also No. 1. That is, researchers discovered this B-complex vitamin first — hence its B1 name.

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You may be more familiar with another B vitamin, folate (vitamin B9), which helps prevent birth defects. But thiamine (vitamin B1) is equally important for keeping your body, brain and heart healthy.

“Thiamine helps break down carbohydrates for energy,” says registered dietitian Amanda Igel, MS, RD, LD. “Your liver stores a small amount of thiamine. But since your body doesn’t naturally make it, you must get thiamine every day from foods or, in some cases, supplements.”

Your body needs vitamin B1 (thiamine) to make adenosine triphosphate (ATP). All the cells in your body use and store ATP for energy.

That’s important enough on its own. But research suggests vitamin B1 also may offer these six health benefits:

“Your heart needs a constant supply of energy to keep it pumping,” says Igel. “Not getting enough thiamine can affect how well your heart works.” As many as 1 in 3 people with congestive heart failure have a thiamine deficiency. Not getting enough thiamine in your diet can lead to a type of heart failure called cardiac or “wet” beriberi.

“Beriberi is the medical term for diseases caused by thiamine deficiency,” says Igel. “There are different beriberi diseases, depending on the affected body system.”

Cardiac or “wet” beriberi causes congestive heart failure, swelling in your legs (edema), difficulty breathing and neck veins that stick out. Some studies indicate that taking thiamine supplements every day can improve these symptoms.

The other type of beriberi — dry beriberi — affects your nervous system. Your nervous system sends signals from your brain to your body, telling it what to do. It controls your movements, thoughts and automatic responses, such as breathing and digestion.

Dry beriberi has the biggest effect on your peripheral nerves, which send signals to your brain to help you feel sensations like hot and cold. Peripheral nerves also aid balance and coordination. “Not getting enough thiamine can interfere with these signals,” says Igel.

Dry beriberi can cause peripheral neuropathy and these symptoms:

Clumsiness or loss of balance.
Lower leg paralysis.
Loss of sensation in your feet (making walking difficult) and hands (so you can’t feel temperatures or textures).
Muscle weakness.
Nerve pain or a pins-and-needles sensation.

When dry beriberi is caught early, you may be able to stop and reverse nervous system damage by getting more vitamin B1. Depending on the severity of your thiamine deficiency, your healthcare provider may prescribe a daily thiamine supplement or even intravenous thiamine injections.

Your brain also needs thiamine-generated energy to help you think and remember. Severe thiamine deficiency can lead to Wernicke-Korsakoff syndrome. This disorder affects brain health, causing symptoms similar to Alzheimer’s disease.

“People with alcohol use disorder are most at risk because long-term alcohol use interferes with your body’s ability to absorb vitamins,” says Igel. “They’re also more at risk because the calories they consume mostly come from alcohol, which doesn’t contain thiamine.” People who have had gastric bypass surgery are also at risk for Wernicke-Korsakoff syndrome.

Nonhuman studies indicate that chronically low levels of thiamine can lead to protein build-up in the brain. These proteins form plaques and tangles that cause brain cells to die. These same events occur as Alzheimer’s disease develops, so researchers are exploring whether increasing thiamine amounts may help prevent or slow both brain diseases.

B-complex vitamins, including thiamine, keep your immune system healthy and minimize stress-induced inflammation. A healthy immune system can better protect your body from germs, infections and illnesses. Some experts call vitamin B1 “the anti-stress vitamin” because it helps your body cope during stressful situations.

Diets containing higher intakes of B vitamins, including thiamine, are linked with a lower risk for cataracts. These cloudy areas form on your eye lenses, causing vision problems like blurred or double vision.

For reasons that aren’t clear, people with Type 1 and Type 2 diabetes tend to have low thiamine levels. Researchers are studying whether raising thiamine levels through supplements can improve blood sugar levels and glucose tolerance.

Experts are also interested in whether thiamine supplements can ease diabetes-related neuropathy. This condition causes symptoms similar to peripheral neuropathy, including pain, tingling and burning sensations. You may also lose sensation in your feet and develop diabetes-related foot ulcers.

The amount of thiamine or vitamin B1 (measured in milligrams or mg) you need each day depends on your age, sex and whether you’re pregnant or breastfeeding.

Try to aim for the recommended dietary allowance (RDA). But there are no known side effects or risks if you get more than the RDA. “Like all B vitamins, thiamine is water-soluble,” notes Igel. “Your body flushes out the excess when you pee.”

AgeRecommended Dietary Allowance (RDA)Birth to 6 months0.2 mgInfants 7 months to 12 months0.3 mgChildren 1 year to 3 years0.5 mgChildren 4 years to 8 years0.6 mgChildren 9 years to 13 years0.9 mgFemale teens 14 to 18 years1.0 mgFemale adults ages 18+1.1 mgMale teens 14 to 18 years1.2 mgMale adults ages 18+1.2 mgPregnant or breastfeeding women1.4 mgAgeBirth to 6 monthsRecommended Dietary Allowance (RDA)0.2 mgInfants 7 months to 12 monthsRecommended Dietary Allowance (RDA)0.3 mgChildren 1 year to 3 yearsRecommended Dietary Allowance (RDA)0.5 mgChildren 4 years to 8 yearsRecommended Dietary Allowance (RDA)0.6 mgChildren 9 years to 13 yearsRecommended Dietary Allowance (RDA)0.9 mgFemale teens 14 to 18 yearsRecommended Dietary Allowance (RDA)1.0 mgFemale adults ages 18+Recommended Dietary Allowance (RDA)1.1 mgMale teens 14 to 18 yearsRecommended Dietary Allowance (RDA)1.2 mgMale adults ages 18+Recommended Dietary Allowance (RDA)1.2 mgPregnant or breastfeeding womenRecommended Dietary Allowance (RDA)1.4 mg

Source: National Institutes of Health

Thiamine is a micronutrient, which means small amounts of the vitamin are found in foods you probably eat every day. These include:

Beans and lentils.
Eggs.
Fish, such as salmon, trout and bluefin tuna.
Fortified breakfast cereals and bread.
Pork, beef, poultry and organ meats.
Sunflower seeds.
Whole-grain foods, like brown rice, oatmeal and quinoa.
Yogurt.

Probably not. Regularly eating thiamine-rich foods can ensure you get enough of this B vitamin. If you’re concerned about how much thiamine you’re getting, a healthcare provider can order a blood test to check your thiamine levels.

If your B1 levels are low, they may recommend multivitamins with vitamin B1. You can also buy thiamine tablets and B-complex vitamin supplements. “But a healthy diet is always the best way to get your vitamins,” states Igel.

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