What Deficiency Is B6? Symptoms, Causes, and Solutions

December 11, 2025 •

4 min read

According to the CDC, up to 10% of Americans may have inadequate levels of vitamin B6, although overt clinical deficiency is less common. This condition, also known as pyridoxine deficiency, can impact numerous bodily functions, from the nervous system to the immune system.

Quick Summary

A lack of vitamin B6, or pyridoxine deficiency, can cause anemia, skin issues, neurological problems like neuropathy and seizures, and weaken immune function. It stems from poor diet, malabsorption, or certain medications and medical conditions.

Key Points

Pyridoxine Deficiency: The formal name for a B6 deficiency is pyridoxine deficiency, which can stem from poor absorption or increased metabolic demand, not just diet.
Diverse Symptoms: A lack of vitamin B6 can cause a variety of symptoms, including skin rashes, a swollen tongue, peripheral neuropathy, and mood changes like depression.
Medication Interference: Medications such as isoniazid, antiepileptic drugs, and certain oral contraceptives can deplete B6 levels over time.
Impacts on Anemia: B6 deficiency can lead to microcytic anemia because the vitamin is necessary for the production of hemoglobin, which transports oxygen in red blood cells.
Treatment Through Diet and Supplements: Mild cases can often be addressed through a nutrient-rich diet, while more severe deficiencies may require supplementation under medical supervision.
Who is at Risk: At-risk groups include individuals with kidney disease, alcohol dependence, malabsorption issues (like Celiac or Crohn's disease), and older adults.
Avoid High-Dose Toxicity: While deficiencies are harmful, excessive intake of B6 from supplements can also cause sensory nerve damage, emphasizing the need for proper dosing.

Understanding Vitamin B6 and Its Role in the Body

Vitamin B6, also known as pyridoxine, is an essential water-soluble vitamin involved in over 100 enzymatic reactions critical for metabolism. It plays a key role in the creation of neurotransmitters, the production of antibodies, and the synthesis of hemoglobin. Because the body doesn't store large amounts of B6, a consistent daily intake is important. While dietary deficiency is uncommon in many countries, certain conditions can affect absorption or increase the need for B6.

Causes and Risk Factors for B6 Deficiency

B6 deficiency is often linked to underlying medical conditions or specific medications rather than just a poor diet.

Medical conditions increasing risk:

Malabsorption disorders: Conditions like Crohn's disease and celiac disease can hinder B6 absorption.
Autoimmune and kidney disease: Conditions such as rheumatoid arthritis and impaired kidney function, especially with dialysis, can increase the metabolic clearance of B6.
Alcohol dependence: Chronic alcohol use impairs B6 absorption and increases its excretion.

Medications that can impact B6 levels:

Isoniazid: This antibiotic is known to deplete B6.
Antiepileptic drugs: Some epilepsy medications can disrupt B6 metabolism.
Oral contraceptives: There may be a link between birth control pills and lower B6 status.
Other drugs: Cycloserine, hydralazine, corticosteroids, and penicillamine can also affect B6 levels.

Signs and Symptoms of a B6 Deficiency

The symptoms of B6 deficiency vary and can affect the skin, nervous system, and mental health.

Common symptoms include:

Skin issues: A scaly, itchy rash (dermatitis) may appear on the face and scalp, along with cracks at the corners of the mouth (cheilosis) and a sore, swollen tongue (glossitis).
Neurological problems: Peripheral neuropathy, causing numbness or tingling in the hands and feet, is common. Severe deficiency can lead to seizures, particularly in infants, and balance issues.
Anemia: B6 is crucial for hemoglobin production, so a deficiency can result in microcytic anemia, characterized by small, pale red blood cells.
Mood and immune function: Low B6 can impact neurotransmitter production, leading to depression or irritability. It also weakens the immune system, making individuals more prone to infections.

Diagnosing and Treating B6 Deficiency

Diagnosis involves a clinical assessment and blood tests to measure the active form of B6, pyridoxal 5'-phosphate (PLP). Treatment typically focuses on increasing B6 intake through diet or supplements.

Comparison Table: Dietary vs. Supplemental B6


Feature	Dietary Vitamin B6	Supplemental Vitamin B6 (Pyridoxine)
Source	Found naturally in foods like poultry, fish, organ meats, potatoes, bananas, and fortified cereals.	Available as a single supplement or in multivitamins.
Absorption	Generally well-absorbed, with some variation between sources.	Highly bioavailable, providing a consistent dose.
Dosage	Varies with diet.	Offers precise control, often 10-100 mg for treatment.
Application	Good for prevention and mild deficiency.	Needed for moderate to severe deficiency or when absorption is impaired or medication-related.
Safety	Very low risk of toxicity from food.	High doses (typically over 100 mg long-term) can cause nerve damage.

Dietary Sources of Vitamin B6

Including foods rich in B6 is important for prevention. Good sources include:

Meats and fish: Beef liver, chicken, salmon, and tuna.
Legumes: Chickpeas.
Vegetables: Potatoes.
Fruits: Bananas and watermelon.
Fortified foods: Many cereals are fortified with B6.

Conclusion

What deficiency is B6 is medically known as pyridoxine deficiency, often triggered by medical conditions or medications rather than solely insufficient diet. This deficiency can lead to significant issues, impacting neurological function, skin health, and the immune system. Symptoms range from peripheral neuropathy and anemia to mood changes and seizures. Recognizing risk factors and symptoms allows for timely diagnosis and management, often involving dietary adjustments and targeted supplementation under medical guidance, to restore B6 levels and improve health.

For further information on vitamin B6, consult the NIH Office of Dietary Supplements fact sheet. Always seek advice from a healthcare professional for diagnosis and treatment.

Navigating Vitamin B6 Deficiency: Key Actions

Identify Your Risk Factors: Individuals with chronic kidney disease, alcohol dependence, or malabsorption issues are at higher risk for a B6 deficiency and should be monitored closely.
Recognize the Symptoms: Pay attention to signs like skin rashes, a sore tongue, numbness in your extremities, or unexplained fatigue, as these can point to a B6 deficiency.
Check Your Medications: Certain drugs, including some antiepileptics and isoniazid, can interfere with B6 metabolism, so discuss your risk with your doctor.
Diversify Your Diet: Incorporate a variety of B6-rich foods, such as fish, poultry, chickpeas, and bananas, to ensure consistent intake.
Avoid High-Dose Supplementation Without Guidance: While supplementation is effective, taking very high doses long-term can cause nerve damage; always consult a doctor for the correct dosage.

Frequently Asked Questions

While inadequate diet can be a factor, B6 deficiency is most commonly caused by underlying medical conditions that affect absorption, such as kidney disease or autoimmune disorders, and the use of certain medications like isoniazid.

Yes, B6 deficiency can significantly impact mental health. It is involved in the synthesis of important neurotransmitters like serotonin and dopamine, and low levels can lead to symptoms such as depression, irritability, and confusion.

Neurological symptoms can include peripheral neuropathy, which manifests as numbness, tingling, or a 'pins and needles' sensation in the hands and feet. In severe cases, it can cause seizures and balance problems.

Diagnosis is typically made through a combination of evaluating a patient's clinical symptoms and lifestyle factors, and confirming with blood tests to measure pyridoxal 5'-phosphate (PLP) concentrations.

Foods rich in vitamin B6 include beef liver, salmon, tuna, chickpeas, potatoes, bananas, and fortified breakfast cereals. A varied diet with these items helps ensure sufficient intake.

Yes, while rare from food sources, excessive B6 intake from supplements can lead to toxicity, causing sensory nerve damage and a lack of muscle coordination (ataxia) at high doses.

Yes, a deficiency can cause a specific type of anemia called microcytic anemia, characterized by small, pale red blood cells. This is because B6 is needed to produce hemoglobin, which carries oxygen.