11 Silent Signs of a Thiamine Deficiency

Updated: Jul. 29, 2020

See if any of these silent signs of a thiamine deficiency sound familiar—and why you should be concerned if you're running low.

What is a thiamine deficiency?

You may not know much about thiamine, aka vitamin B1. Despite its lack of notoriety, thiamine is important. Your body needs it to help burn carbohydrates for energy and for your nerves to function properly, according to the U.S. National Library of Medicine. Thiamine also plays an important role in heart and muscle function, says Lisa Andrews, RD, a dietitian in Cincinnati, Ohio.

Because thiamine is water-soluble, your body doesn’t store it for long periods of time; you need a steady supply to avoid a deficiency. You can get enough through food, supplements, or both. The best food sources of thiamine include fortified breakfast cereals, pork, enriched white rice, trout, mussels, and black beans. Thiamine is included in many multivitamins and in many B complex vitamins. The recommended intake is 1.2 milligrams per day for men, and 1.1 milligrams daily for women—you can get that from a single serving or breakfast cereal or a pork chop. Pregnant or nursing? You’ll need 1.4 milligrams per day. Here are 11 silent signs of a thiamine deficiency to watch for.

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Thiamine deficiency symptoms

Feeling run down can be a sign of stress, poor sleep, or it could be a lack of thiamine in your diet. If you’re constantly battling fatigue, you might want to talk to your doctor about a potential lack of thiamine.

You’re exhausted or are having memory problems

Feeling tired can be a symptom of many medical conditions. With thiamine deficiency, you’ll feel fatigued because your body needs thiamine to generate energy from nutrients. “Mental confusion is a common sign of thiamine deficiency too,” says Andrews. “Thiamine is needed for various enzymes that are vital to glucose metabolism in the brain.” The brain specifically requires glucose as an energy source. It’s needed for neurons and brain cells to properly function. Learn the silent signs you aren’t getting enough nutrients.

Your muscles are weak or you’re losing weight

“Deficiency of thiamine is known as beriberi,” says Andrews. “When we don’t get adequate thiamine from a lack of it in our diet or for other reasons, metabolism of glucose is affected. And we may experience muscle weakness, fatigue, memory loss, loss of appetite, and weight loss.” If untreated, beriberi can in extreme cases cause congestive heart failure or death, according to the National Institutes of Health (NIH).

You’re not hungry

“Thiamine plays a role in the brain’s hypothalamus, a gland that controls appetite and hunger,” says Andrews. “When there is a thiamine deficiency, the brain thinks it’s full and loss of appetite may occur.” Find out the ways your body is telling you that you’re running low on key vitamins.

Your arms or legs are numb or tingling

People with chronic alcoholism, a drug-use disorder, a severe gastrointestinal disorder, or AIDS are at risk for Wernicke-Korsakoff syndrome. A main symptom of the syndrome is encephalopathy, and people with this condition often experience peripheral neuropathy. “This is a condition in which nerves that carry messages to and from the brain are damaged due to thiamine deficiency,” says Andrews. “Signs may include numbness or tingling in the arms and legs.” Wernicke-Korsakoff syndrome may also cause Korsakoff’s psychosis. Symptoms include short-term memory loss, disorientation, and confusion. Rapid treatment is critical because up to 20 percent of people at the encephalopathy stage and 25 percent of people in the psychosis stage die, according to the NIH.

Your newborn has diarrhea or is vomiting

When a mom deficient in thiamine breastfeeds a newborn, the baby can experience scary symptoms—including shortness of breath, a bluish cast to the skin, diarrhea, and vomiting, according to the Mayo Clinic Laboratories. Thiamine isn’t the only B vitamin you could be deficient in. Here are more signs you could be deficient in B vitamins.

Thiamine deficiency causes

Behaviors, medications, and certain conditions can both inhibit your absorption of this vital B vitamin.

You have a drinking problem

For alcoholics, there’s a double-edged sword with thiamine. “Alcohol reduces thiamine absorption,” explains Andrews. “And alcoholics are at high risk for thiamine deficiency because of poor food intake, increased thiamine requirements for alcohol metabolism, and increased thiamine loss in the urine.” Not sure if your alcohol intake is problematic? These are the signs you’re drinking too much.

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You’re taking water pills

“People taking diuretics may be at risk from losing too much thiamine in the urine,” says Andrews. In a study in the Journal of the American College of Cardiology, 33 percent of people with congestive heart failure were deficient in thiamine, versus only 12 percent of healthy people. With water pills and thiamine deficiency, it’s a bit of a “which came first” question. “Thiamine deficiency may lead to heart failure, and the treatment of heart failure with high-dose diuretic use may lead to thiamine deficiency,” notes Andrews. One study in the American Journal of Medicine found that the diuretic furosemide, commonly prescribed to heart failure patients, may inhibit how the body’s cells absorb thiamine. The study also states that increased urine volume and urinary flow rates of heart-failure patients may lead to thiamine deficiency.

You have diabetes

People with type 1 or type 2 diabetes may be more likely to have a thiamine deficiency. In a study published in Diabetes & Vascular Disease Research, 8 percent of diabetes patients were mildly deficient in thiamine, while 32 percent were moderately deficient. It’s possible that the kidneys may by clearing more thiamine from the bodies of people with diabetes. See our list of the best foods for diabetics.

You had bariatric surgery

Nutrient malabsorption is a risk of bariatric surgery, and thiamine deficiency caused by the surgery can lead to beriberi or Wernicke’s encephalopathy. Most bariatric surgery patients are prescribed micronutrient supplements, including thiamine. These are the supplements doctors take every day.

Thiamine deficiency tests

Urinary concentration of thiamine

Your thiamine level can be measured through a urine test. The results will provide an idea of how much thiamine you’re taking in through your diet—but not how much your body is storing. An insufficient thiamine intake would be a level below 0.1 milligrams per day, and less than 0.04 milligrams per day would be considered incredibly low, according to the NIH.

Blood levels of thiamine

Your thiamine level also can be measured through a blood test. Because the body can store only a limited amount of thiamine, a deficiency can happen quickly—in as little as 10 days.