Vitamin B₆ (pyridoxine)

Vitamin B₆ (pyridoxine) – role, norms and violations

Vitamin B₆ is a group of compounds (pyridoxine, pyridoxal, pyridoxamine) that play a key role in the metabolism of amino acidsAmino acids are the fundamental building blocks of proteins and play a key role in biological processes. There are a total of 22 standard amino acids used for protein synthesis in living organisms., the synthesis of neurotransmitters and hemoglobin. The body can’t synthesize it, so it has to come from food.

1. The role of vitamin B₆ in the body

Protein metabolism -participates in the breakdown and synthesis of amino acids.
Synthesis of neurotransmitters -serotonin, dopamineDopamine is a neurotransmitter and hormone that plays a key role in the brain's reward system, motivation, pleasure, learning, and movement regulation.Main functions: Stimulates feelings of pleasure and satisfaction. Involved in motivation and decision-making processes. Regulates motor activity. Affects memory, attention, and mood., GABA (regulation of mood and sleep).
Formation of hemoglobin -necessary for the synthesis of heme.
Immune support -affects the production of antibodies.
Hormone regulation -helps control levels of estrogen, testosterone, and cortisol.
Reduction of homocysteine (together with B₉ and B₁₂) – prevention of cardiovascular diseases.

Active form: Pyridoxal-5-phosphate– PLP) – it is its level that is measured in the blood.

2. The norm of vitamin B₆ in the blood

Indicator	Standard
Pyridoxal-5-phosphate (PLP)	20-125 nmol / l (5-30 ng / ml)
Total Vitamin B₆	5-30 mcg/l

Note:

In pregnant and elderly people, the need for B₆ increases.
A PLP level below 20 nmol / L indicates a deficiency.

3. Vitamin B3 Deficiency: causes and symptoms

Causes of the deficit:

Lack of food – a diet without meat, fish, nuts.
Alcoholism -disrupts the assimilation of B₆.
Chronic diseases (kidney failure, celiac disease).
Medications (isoniazid, oral contraceptives, penicillamine).

Symptoms:

Dermatitis (peeling of the skin, cracks in the corners of the mouth-cheilosis).
Glossitis (inflammation of the tongue).
Microcytic anemia (due to impaired heme synthesis).
Neurological disorders – depression, confusion, seizures.
Weakened immune system– frequent infections.

Risk groups:

Pregnant women (especially with toxicosis).
People with autoimmune diseases (rheumatoid arthritis).

4. Excess vitamin B₆: is it possible and dangerous?

Overdose of natural B₆ from food is not possible. However , long-term use of high-dose supplements (>100 mg / day) causes:

Symptoms of hypervitaminosis:

Neuropathy – numbness and tingling in the hands/feet (reversible after withdrawal).
Photosensitivity – increased sensitivity to light.
Nausea, heartburn.

Upper limit: 100 mg / day (for adults).

5. Diagnosis and treatment

Analyzes:

PLP (pyridoxal-5-phosphate) in plasma is the main marker.
Homocysteine (increases with B₆ deficiency).
General blood test(anemia, microcytosis).

Deficit management:

Pyridoxine preparations(10-50 mg / day).
For neuropathy due to isoniazid – up to 100 mg / day.
Diet:
Animal sources: chicken, salmon, liver.
Vegetable sources: bananas, potatoes, chickpeas, walnuts.

In case of overdose:

Cancellation of supplements.
Symptomatic therapy (for example, pain relief for neuropathy).

6. Examples of interpreting results

PLP level	Homocysteine	Symptoms	Diagnosis
< 20 nmol/l	↑	Dermatitis, anemia	Deficit B₆
> 125 nmol / l	Standard	Neuropathy	Overdose B₆
Standard	↑	–	B₉ or B₁₂ deficiency

Important: A B₆ deficiency is often combined with a lack of other B vitamins (especially B₂ and B₃).

Daily consumption rates

Adults: 1.3-1.7 mg.
Pregnant women: 1.9 mg.
Nursing mothers: 2.0 mg.

Toxicity: Prolonged use of >200 mg / day may cause irreversible neuropathy.