What does B6 deplete?

October 30, 2025 •

3 min read

According to the CDC, up to 10% of Americans may have inadequate vitamin B6 levels. Understanding what does B6 deplete is vital for maintaining optimal health, as various medications, medical conditions, and lifestyle choices can compromise this essential vitamin.

Quick Summary

Vitamin B6 levels can be depleted by specific medications like isoniazid, alcohol consumption, kidney disease, autoimmune disorders, and gastrointestinal malabsorption issues.

Key Points

Medications: Certain drugs, notably isoniazid, some anticonvulsants, and corticosteroids, can directly interfere with B6 metabolism, causing depletion.
Alcohol Use: Chronic, heavy alcohol consumption depletes B6 by increasing its metabolic breakdown and inhibiting intestinal absorption.
Kidney Disease: Impaired kidney function and dialysis can lead to an excessive clearance of B6 from the body.
Malabsorption: Gastrointestinal conditions like inflammatory bowel disease (IBD) and celiac disease reduce the body's ability to absorb B6 from food.
Inflammation: Autoimmune disorders increase the catabolism of B6, leading to a higher demand for the vitamin.
Gut Health: Alcohol can disrupt gut microbiota, reducing the bacterial production of B6 and contributing to deficiency.
Secondary Condition: B6 deficiency is often not an isolated dietary problem but a secondary symptom of an underlying medical or lifestyle issue.

Vitamin B6, or pyridoxine, is a water-soluble nutrient essential for over 100 enzymatic reactions in the body. While a balanced diet typically provides sufficient B6, many factors can lead to its depletion, necessitating an understanding of the causes beyond simple dietary deficiency. These depletions can be caused by various medications, chronic diseases, and specific lifestyle habits.

Medications That Deplete B6

Certain pharmaceutical drugs can interfere with vitamin B6 metabolism, leading to a deficiency. This can occur through increased excretion, competition with B6 for metabolic enzymes, or inhibiting its absorption.

Tuberculosis Medications

Drugs like Isoniazid (INH) are primary causes of drug-induced B6 deficiency, interfering with B6 synthesis and increasing its excretion. Cycloserine, a second-line drug, can also increase the renal excretion of B6.

Anticonvulsants

Phenytoin and Carbamazepine, among other enzyme-inducing antiepileptic drugs, can increase the breakdown of vitamin B6.

Other Depleting Medications

Other medications that can interfere with B6 levels or metabolism include Hydralazine, Penicillamine, some Oral Contraceptives (especially with long-term use), Theophylline, and Corticosteroids.

Medical Conditions Causing B6 Depletion

Chronic health issues can increase B6 requirements or decrease absorption. Low B6 levels are often linked with other B vitamin deficiencies.

Kidney Disease

Patients with impaired renal function, particularly those on hemodialysis, are at higher risk of deficiency due to increased metabolic clearance of active B6.

Autoimmune and Inflammatory Disorders

Conditions like Rheumatoid Arthritis and other autoimmune diseases can increase the body's consumption and breakdown of B6. Inflammatory Bowel Diseases (IBD) like Crohn's and ulcerative colitis, and Celiac Disease, can cause malabsorption.

Other Conditions

Chronic Liver Disease can impair the liver's ability to convert B6 to its active form. Hyperthyroidism may increase the need for B vitamins. Rare Genetic Disorders can also disrupt B6 pathways.

Lifestyle and Dietary Factors

Lifestyle habits and dietary choices can significantly impact B6 status.

Chronic Alcohol Use

Chronic alcohol dependence is a major cause of B6 depletion. Alcohol's metabolite, acetaldehyde, accelerates the degradation of active B6. Heavy alcohol use also correlates with poor diet and impaired absorption.

Poor Dietary Choices

While severe dietary B6 deficiency is uncommon in developed countries, suboptimal intake can occur. Plant-based diets may require careful planning as B6 from meat is more bioavailable. Poor overall nutrition is also a risk factor, especially in older adults.

Comparison of Major B6 Depletors


Depletor Category	Examples	Primary Mechanism of Depletion	At-Risk Populations
Medications	Isoniazid, Phenytoin, Cycloserine, Hydralazine, Corticosteroids	Interference: Drugs form complexes with B6, increasing excretion; Increase metabolic breakdown; Inhibit enzymes activating B6	Patients with tuberculosis, epilepsy, hypertension, autoimmune conditions, or long-term steroid use
Medical Conditions	Kidney disease, Autoimmune disorders (e.g., Crohn's, RA), Chronic Liver Disease	Impaired Metabolism: Increased B6 clearance; Autoimmune-induced higher catabolism; Decreased gut absorption	Patients undergoing dialysis, those with inflammatory bowel diseases, or chronic liver issues
Lifestyle	Chronic alcohol use, Poor dietary intake	Accelerated Degradation: Acetaldehyde (alcohol metabolite) hastens B6 breakdown; Poor diet and malabsorption	Individuals with alcohol dependence, older adults, and those with very restrictive diets

The Role of Gut Microbiota

Research suggests chronic alcohol consumption disrupts gut microbiota, reducing microbial production of B6, further contributing to deficiency.

Conclusion

Vitamin B6 deficiency is often a secondary symptom of underlying issues. Chronic alcohol use, medications like isoniazid and anticonvulsants, and conditions such as kidney disease and malabsorption syndromes are known B6 depletors. Addressing these root causes is crucial. Supplementation may be needed for those at risk to prevent complications. Consult a healthcare provider to determine the cause of deficiency and treatment. Information is available from the National Institutes of Health's Office of Dietary Supplements.

National Institutes of Health (NIH) Office of Dietary Supplements

Frequently Asked Questions

Common medications that can deplete B6 include isoniazid (for tuberculosis), cycloserine, certain anticonvulsants like phenytoin and carbamazepine, theophylline (for asthma), and corticosteroids.

Chronic alcohol use depletes B6 in several ways: its metabolite, acetaldehyde, accelerates the degradation of active B6, it causes poor dietary intake, and it leads to impaired absorption.

Yes, individuals with kidney disease, particularly those undergoing hemodialysis, are at a higher risk of B6 deficiency due to the increased metabolic clearance of the active form of the vitamin.

Yes, these conditions cause intestinal damage and inflammation that can significantly impair the absorption of nutrients, including vitamin B6, from the digestive tract.

Autoimmune disorders like rheumatoid arthritis can cause increased catabolism, or breakdown, of B6, which means the body uses up the vitamin more quickly than normal.

While less common than depletion from other causes, a consistently poor diet, restrictive diets, or poor nutritional status, especially in older adults, can lead to inadequate B6 levels over time.

For drug-induced B6 deficiency, a healthcare provider may recommend supplementation with pyridoxine alongside the medication. For example, patients on isoniazid are often prescribed a prophylactic B6 dose to prevent neuropathy.