Who Is Most Likely to Suffer From a Thiamine Deficiency?

October 28, 2025 •

3 min read

An estimated 15–80% of individuals with chronic alcohol use disorder develop thiamine deficiency. This makes them one of the highest-risk groups for a thiamine deficiency, a condition that can also impact those with certain medical conditions, post-surgical patients, and malnourished populations.

Quick Summary

Certain groups face a heightened risk of low thiamine levels due to poor diet, impaired nutrient absorption, or increased metabolic demand, including those with alcohol use disorder, bariatric surgery patients, and pregnant women with severe vomiting.

Key Points

Alcohol Use Disorder: The most common cause of thiamine deficiency in developed countries is chronic alcohol abuse due to poor diet, impaired absorption, and increased excretion.
Bariatric Surgery: Patients who undergo weight-loss surgery are at increased risk due to altered anatomy leading to malabsorption, reduced intake, and vomiting.
Malnutrition and Restrictive Diets: Individuals with eating disorders like anorexia or those relying heavily on refined carbohydrates are prone to deficiency.
Pregnancy Complications: Pregnant women with severe vomiting (hyperemesis gravidarum) have a higher risk, which can also affect their infants if they are breastfed.
Chronic Illnesses: Conditions such as heart failure, HIV/AIDS, cancer, and diabetes can increase thiamine needs or affect its metabolism.
Diuretic Use: Certain medications, especially loop diuretics, can lead to increased urinary loss of thiamine.
Genetic Factors: Rare inherited disorders can impair thiamine transport or metabolism.

What is a Thiamine Deficiency?

Thiamine, or vitamin B1, is a vital water-soluble vitamin needed for metabolism and cellular function. Since the body doesn't store much of it, a steady intake through diet is necessary. Thiamine helps convert food, especially carbohydrates, into energy and is crucial for the nervous system and heart. A deficiency can lead to serious conditions like beriberi and Wernicke-Korsakoff syndrome if not addressed. While rare in places with a stable food supply, some groups are more vulnerable due to diet, lifestyle, or health issues.

Primary Risk Groups for Thiamine Deficiency

Individuals with Alcohol Use Disorder

Chronic alcohol abuse is a major cause of severe thiamine deficiency in developed nations. Alcohol affects thiamine levels in several ways:

Poor diet
Reduced absorption in the intestines
Problems with liver storage and activation
Increased loss through urine

This leads to a high rate of deficiency in this population, often resulting in Wernicke-Korsakoff syndrome, a serious brain disorder.

Patients Undergoing Bariatric Surgery

Weight-loss surgeries, particularly gastric bypass, increase the risk of thiamine deficiency. Changes to the digestive system disrupt nutrient absorption. Risks include:

Malabsorption from bypassing key areas where thiamine is absorbed.
Limited food intake and vomiting after surgery, depleting thiamine.
Not taking recommended vitamin supplements.

Malnourished Individuals

People with inadequate nutrition from any cause are at high risk. This includes:

Severe anorexia nervosa, leading to very low vitamin intake.
Diets high in refined grains (like polished rice), which lack thiamine and historically caused beriberi.
Long-term IV feeding without enough thiamine.

Pregnant and Lactating Women

Pregnancy and breastfeeding increase the need for thiamine to support the baby.

Severe, persistent vomiting in pregnancy (hyperemesis gravidarum) can deplete thiamine and potentially cause Wernicke's encephalopathy.
Babies breastfed by thiamine-deficient mothers are at risk of infantile beriberi.

Other Contributing Medical Conditions and Factors

Other health issues can also increase the risk of thiamine deficiency:

Chronic illnesses like cancer, HIV/AIDS, kidney disease, and heart failure are linked to poor nutrition and nutrient loss.
Loop diuretics can increase thiamine loss in urine.
Digestive problems like chronic diarrhea or malabsorption syndromes hinder thiamine uptake.
Rare genetic conditions can affect thiamine transport.
Drinking large amounts of coffee and tea, and eating some raw seafood, can interfere with thiamine absorption.

Comparison of Risk Factors


Category	High-Risk Groups	Contributing Factors	Symptoms/Outcomes (often severe)
Dietary	Malnourished individuals, heavy refined grain diets (e.g., polished rice)	Starvation, lack of fortified foods, high carbohydrate intake increasing metabolic demand	Beriberi (wet or dry), fatigue, irritability, neurological damage
Lifestyle	Chronic alcohol users	Poor intake, impaired absorption, storage, and increased excretion due to alcohol	Wernicke-Korsakoff syndrome, confusion, memory loss, ataxia, eye problems
Surgical	Bariatric surgery patients	Malabsorption from altered anatomy, post-operative vomiting, nonadherence to supplements	Neurological issues, peripheral neuropathy, beriberi
Medical	Chronic illness patients (HIV, cancer, diabetes, heart failure)	Increased metabolic demand, poor appetite, chronic inflammation, drug interactions	Beriberi, neurological symptoms, varied according to underlying condition
Pregnancy/Lactation	Pregnant women with hyperemesis, nursing mothers	Increased demand for fetal/infant growth, severe vomiting leading to depletion	Wernicke's encephalopathy, infantile beriberi, neurological/cardiac issues in mother and child

Prevention and Treatment Strategies

Preventing thiamine deficiency involves eating thiamine-rich foods such as whole grains, pork, and legumes. Many foods are fortified with thiamine in some countries. High-risk individuals may need oral thiamine supplements.

Treating a deficiency often involves high-dose thiamine, sometimes given intravenously or intramuscularly, especially in severe cases or to prevent Wernicke-Korsakoff syndrome. Early treatment is vital to avoid lasting nerve damage. Addressing the root cause, like alcohol use disorder, is also key to long-term recovery.

Conclusion

While not common for everyone in industrialized nations, thiamine deficiency poses a significant risk to several groups. Chronic alcohol abuse is a major culprit, but those with chronic diseases, bariatric surgery patients, malnourished individuals, and pregnant women with severe vomiting are also highly vulnerable. Recognizing the symptoms and getting medical help quickly is crucial for those at risk. Eating a balanced diet, consuming fortified foods, or taking supplements are effective ways to prevent the serious complications of thiamine deficiency. The National Institutes of Health is a reliable source for more information.

Frequently Asked Questions

The most severe consequence is Wernicke-Korsakoff syndrome, a neurological disorder primarily affecting people with chronic alcohol use disorder that can cause irreversible brain damage.

After bariatric surgery, patients are at risk due to reduced food intake, persistent vomiting, and altered digestive anatomy that impairs the absorption of thiamine.

Yes, large amounts of coffee and tea contain anti-thiamine factors like polyphenols that can interfere with thiamine absorption.

Early symptoms are often vague and can include fatigue, irritability, poor memory, loss of appetite, and sleep disturbances.

Thiamine deficiency is treated with supplements, which are usually taken orally. In severe cases, particularly with neurological symptoms, high-dose intravenous or intramuscular thiamine may be administered under medical supervision.

Yes, breastfed infants are at risk if their mother has a thiamine deficiency, as the vitamin is secreted through breast milk. This can lead to infantile beriberi.

Yes, severe anorexia nervosa and other eating disorders cause significantly low dietary intake, which is a major risk factor for developing thiamine deficiency.

If you suspect a thiamine deficiency, it is crucial to consult a healthcare provider for a proper diagnosis and treatment plan, as early intervention can prevent severe complications.