Why B6 Matters
Vitamin B6 (pyridoxine) is a cofactor for over 100 enzyme reactions, particularly in amino acid metabolism, neurotransmitter synthesis, and haemoglobin production.Causes of Deficiency
- Chronic alcohol excess (most common cause in developed countries)
- Certain medications: isoniazid (TB treatment), some anti-epileptics, penicillamine
- Malabsorption conditions (coeliac disease, IBD)
- Kidney disease (increased losses)
- Poor dietary intake (rare in developed countries)
Symptoms of Deficiency
| System | Symptoms |
|---|---|
| Nervous system | Peripheral neuropathy — numbness, tingling, burning in hands/feet |
| Blood | Microcytic anaemia (unusual — B6 deficiency can mimic iron deficiency) |
| Skin | Dermatitis, cracks at corners of mouth |
| Mood | Depression, confusion (severe deficiency) |
Very High-Dose Supplements Can Cause HarmIronically, excessive vitamin B6 supplementation (often from high-dose over-the-counter supplements, >200mg/day for prolonged periods) can cause peripheral neuropathy — the same symptom as deficiency. Stick to recommended doses unless medically supervised.
Isoniazid and B6Anyone taking isoniazid for tuberculosis treatment is routinely co-prescribed vitamin B6 to prevent medication-induced peripheral neuropathy — a well-established drug interaction.
What foods are rich in vitamin B6?
Poultry, fish, potatoes, chickpeas, bananas, and fortified cereals are good sources. Deficiency from diet alone is uncommon in developed countries with varied diets.
Can B6 deficiency cause anaemia?
Yes — B6 deficiency can cause a sideroblastic anaemia, which can look similar to iron deficiency anaemia on a blood film, so B6 should be considered if iron studies are normal.
Is B6 testing routine?
No, it's not part of standard blood panels — it's specifically requested when peripheral neuropathy, unexplained anaemia, or relevant risk factors (alcohol excess, certain medications) are present.
Medical Disclaimer: This page is for general education only and does not replace professional medical advice. Always consult a qualified healthcare provider.