What is the mechanism behind thiamine (Vitamin B1) causing pedal edema?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: April 2, 2025View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

From the Guidelines

Thiamine deficiency, not thiamine itself, causes feet swelling, and it is crucial to initiate treatment immediately if deficiency is suspected, as it can lead to severe complications such as beriberi, which affects the cardiovascular system and causes peripheral vasodilation, increased blood flow to extremities, and reduced systemic vascular resistance, resulting in fluid retention and edema. When the body lacks sufficient thiamine (vitamin B1), it disrupts normal cellular metabolism, particularly affecting the cardiovascular system. This deficiency leads to a condition called beriberi, which has two main forms: dry and wet. Wet beriberi specifically affects the cardiovascular system, causing peripheral vasodilation, increased blood flow to extremities, and reduced systemic vascular resistance. These changes lead to fluid retention and edema, particularly noticeable in the feet and lower legs. Additionally, thiamine deficiency impairs the heart's ability to pump effectively, further contributing to fluid accumulation in the extremities. The body's cells also struggle to maintain proper fluid balance without adequate thiamine, as it plays a crucial role in cellular energy production and membrane integrity. According to the British Obesity and Metabolic Surgery Society guidelines, treatment involves thiamine supplementation, and clinicians should be educated about the factors that may predispose to thiamine deficiency and the importance of initiating immediate treatment, as stated in the guidelines 1.

Some key points to consider in the management of thiamine deficiency include:

  • Initiating treatment immediately if deficiency is suspected, without delaying pending blood results, as recommended by the British Obesity and Metabolic Surgery Society guidelines 1
  • Recommending a complete multivitamin and mineral supplement containing at least government dietary recommendations for thiamine, as suggested by the guidelines 1
  • Considering oral thiamine or vitamin B co-strong tablets for the first 3- to 4-month post-surgery, as recommended by the guidelines 1
  • Prescribing oral thiamine 200–300 mg daily, vitamin B co-strong 1 or 2 tablets, three times a day to people with symptoms such as dysphagia, vomiting, poor dietary intake, or fast weight loss, as recommended by the guidelines 1.

It is essential to prioritize the patient's morbidity, mortality, and quality of life when managing thiamine deficiency, and to follow the most recent and highest-quality guidelines, such as those from the British Obesity and Metabolic Surgery Society 1.

From the Research

Thiamine and Feet Swelling

  • Thiamine deficiency can lead to various health issues, including wet beriberi, which is characterized by cardiovascular symptoms such as heart failure and peripheral edema, including feet swelling 2, 3, 4.
  • The mechanism behind thiamine causing feet swelling is related to its role in glucose metabolism and energy production in the body. Thiamine deficiency can lead to impaired energy production, resulting in increased lactate production and subsequent fluid accumulation in the body, including in the feet 2, 5.
  • Furosemide, a diuretic commonly used to treat heart failure, can exacerbate thiamine deficiency by increasing urinary thiamine excretion, which can further contribute to feet swelling 3, 5, 6.
  • Thiamine supplementation has been shown to improve symptoms of thiamine deficiency, including feet swelling, in patients with heart failure and other conditions 4, 5, 6.
  • The exact mechanism of thiamine deficiency leading to feet swelling is not fully understood and may involve multiple factors, including impaired cardiac function, increased vascular permeability, and altered electrolyte balance 3, 5.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Role of Thiamin in Health and Disease.

Nutrition in clinical practice : official publication of the American Society for Parenteral and Enteral Nutrition, 2019

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.