Vitamin B6 Deficiency: Causes, Symptoms, and Sources

Causes of Vitamin B6 Deficiency

Vitamin B6 deficiency often occurs alongside deficiencies in other B vitamins, such as folate (Vitamin B9) and Vitamin B12. Although it's uncommon due to its wide availability in food, several factors can contribute to its deficiency:

1. Medical Conditions Affecting Absorption

Certain autoimmune and inflammatory disorders can interfere with the absorption of Vitamin B6, including:

• Celiac disease
• Ulcerative colitis
• Crohn's disease
• Rheumatoid arthritis
• HIV/AIDS
• Kidney disorders

2. Medications That Inactivate Vitamin B6

Some drugs reduce the body's ability to absorb or utilize Vitamin B6, such as:

• Anticonvulsants
• Isoniazid (for tuberculosis)
• Cycloserine (antibiotic)
• Hydralazine (used to lower blood pressure)
• Corticosteroids
• Penicillamine (used in Wilson’s disease)

3. Other Contributing Factors

• Homocystinuria, a rare metabolic disorder
• Hyperthyroidism
• Protein-energy malnutrition
• Chronic alcoholism
• Undergoing dialysis

Symptoms of Vitamin B6 Deficiency

Vitamin B6 deficiency may mimic pellagra, a condition caused by niacin (Vitamin B3) deficiency. Common symptoms include:

Fatigue and Low Energy

Due to its role in red blood cell production, a deficiency may lead to anemia, resulting in fatigue and weakness.

Cracked and Sore Lips

Dry, cracked lips and mouth corners are common, along with swelling, redness, and potential bleeding or infection.

Weakened Immune System

The body becomes more susceptible to infections. Conditions like cancer may deplete B6 levels, increasing the need for supplementation under medical supervision.

Skin Rash

Deficiency can cause seborrheic dermatitis — red, itchy, and flaky skin, often appearing on the scalp, face, neck, and upper chest.

Glossitis (Inflamed Tongue)

The tongue becomes swollen, sore, and smooth due to the loss of papillae, affecting chewing, swallowing, and speech.

Nerve Pain and Tingling

Peripheral neuropathy can result in burning sensations, numbness, and difficulty walking, especially in the hands and feet.

Mood Swings

Deficiency can influence mood by disrupting neurotransmitter production (e.g., serotonin, GABA), leading to depression, irritability, and anxiety. A 2017 study found that B6 supplements helped reduce premenstrual syndrome (PMS) symptoms in women.

Seizures in Infants

Infants exclusively breastfed past six months without complementary foods may experience seizures due to severe deficiency. These seizures may persist despite anticonvulsant treatment.

Cognitive Decline and Alzheimer’s Risk

In older adults, B6 deficiency — especially when paired with folate and B12 deficiencies — can raise homocysteine levels, increasing the risk of Alzheimer’s and heart disease. Observational studies have linked low B vitamin intake with cognitive impairment and Alzheimer’s, though further research is needed.

Diagnosing Vitamin B6 Deficiency

Diagnosis involves assessing symptoms and conducting lab tests. In infants, seizures or developmental issues may prompt testing. One common test is measuring serum pyridoxal phosphate levels in the blood. Multiple tests are often used for accurate diagnosis.

Sources of Vitamin B6

Dietary Sources

A balanced diet typically provides sufficient Vitamin B6. Foods rich in this vitamin include:

• Chickpeas: 1 cup = 1.1 mg (55% of daily value)
• Beef liver: 85g = 0.9 mg (45%)
• Yellowfin tuna: 85g = 0.9 mg (45%)
• Grilled chicken breast: 85g = 0.5 mg (25%)
• Medium banana: 0.4 mg (20%)
• Tofu: ½ cup = 0.1 mg (5%)

Other sources include salmon, turkey, fortified cereals, whole grains, brown rice, carrots, avocado, potatoes, leafy greens like spinach, papaya, oranges, cantaloupe, and nuts such as hazelnuts.

Supplementation

Most people meet their needs through food. However, supplements may be necessary for those with kidney disease, absorption issues, or inherited anemia. Vitamin B6 supplements are commonly found as pyridoxine hydrochloride in multivitamins, B-complex formulations, or standalone B6 supplements.

Recommended Daily Intake

Overview of Vitamin B6

Also known as pyridoxine, Vitamin B6 is a water-soluble vitamin that must be consumed regularly through food, as the body cannot store it. It plays a vital role in protein and carbohydrate metabolism, red blood cell production, brain development, immune function, and hormone regulation.