What it does in the body
- Amino acid metabolism (transamination, decarboxylation) — over 150 PLP-dependent enzymes
- Neurotransmitter synthesis (serotonin, dopamine, GABA, norepinephrine, histamine)
- Hemoglobin synthesis (ALA synthase — rate-limiting step of heme biosynthesis)
- Glycogen phosphorylase cofactor (glycogenolysis)
- Immune function (lymphocyte proliferation and IL-2 production)
How much you need (Daily Value)
| Group | Recommended | Source |
|---|---|---|
| Adult male | 1.3-1.7 mg (higher for age 51+) | NIH/IOM |
| Adult female | 1.3-1.5 mg (higher for age 51+) | NIH/IOM |
| Pregnancy | 1.9 mg | WHO/IOM |
| Children | 0.5-1.0 mg (ages 1-13) | WHO |
| Older adults | 1.7 mg (male), 1.5 mg (female) | NIH |
Richest food sources
| Food | Amount | Where |
|---|---|---|
| Chickpeas (canned) | 1.14 mg per 100g | Middle East/South Asia |
| Beef liver | 1.03 mg per 100g | global |
| Tuna (yellowfin) | 0.93 mg per 100g | global |
| Salmon | 0.64 mg per 100g | global |
| Chicken breast | 0.52 mg per 100g | global |
| Potato (baked with skin) | 0.41 mg per 100g | Americas/Europe |
| Banana | 0.37 mg per 100g | Tropics/global |
| Pistachio nuts | 1.70 mg per 100g | Middle East/Central Asia |
In our food database, per 100 g
Highest among our free foods — open the Food Explorer to compare.
If you don't get enough
Mild: Irritability, depression, confusion, angular cheilitis, glossitis
Moderate: Microcytic sideroblastic anemia (impaired heme synthesis), dermatitis, peripheral neuropathy
Severe: Seizures (especially in infants — pyridoxine-dependent epilepsy), severe depression, immunodeficiency, hyperhomocysteinemia
Time to onset: Mild symptoms within 2-3 weeks; anemia and neuropathy over weeks to months
Too much
Upper limit: 100 mg/day for adults
Chronic doses >200 mg/day cause sensory neuropathy (paradoxical to deficiency symptoms): progressive numbness, ataxia, loss of proprioception. Typically reversible on cessation.
How well you absorb it
75% from food; nearly 100% from supplements
Helped by: Riboflavin (FAD-dependent pyridoxamine-5'-phosphate oxidase converts dietary forms to PLP)
Hindered by: Isoniazid (forms inactive hydrazone with PLP), Cycloserine, Penicillamine, Oral contraceptives (increase tryptophan catabolism, raising B6 demand), Alcohol
Cooking & storage
B6 is moderately heat-sensitive; 10-50% lost during cooking. The pyridoxine glycoside form in plant foods has lower bioavailability (50-60%) compared to animal-source pyridoxal/pyridoxamine. Milling of grains removes substantial B6.
Nutrisize Health totals every nutrient from what you actually eat, against targets set for your age and sex, and flags what's short — across 4,995 foods, on your device.
