II. Physiology
- Vitamin B6 refers to a group of picolines, water-soluble B Vitamins: Pyridoxine, Pyridoxal, and Pyridoxamine
- Vitamin B6 is converted to Pyridoxal Phosphate (PyrP)
- Pyridoxal Phosphate is an important coenzyme, a Cofactor for more than 100 enzymes (esp. Amino Acid synthesis)
- Amino Acid synthesis (including all transamination, in which it is a Cofactor for all transaminases)
- Alanine (and 2-ketoglutarate) are synthesized from pyruvate and Glutamate via PyrP assisted enzyme
- Glutamate (and oxaloacetate) are synthesized from 2-ketoglutarate and Aspartate via PyrP assisted enzyme
- Histamine is sythesized from Histamine via PyrP assisted enzyme
- Cystathionine is sythesized from Homocysteine and Serine via PyrP assisted enzyme
- Neurotransmitter synthesis (e.g. Serotonin, Norepinephrine, GABA)
- GABA (Gamma-Aminobutyric Acid) is synthesized from Glutamate
- Dopamine is synthesized from Levodopa
- Sphinglipid synthesis
- Glycogen synthesis
- Aminolevulinic Acid
- Amino Acid synthesis (including all transamination, in which it is a Cofactor for all transaminases)
- Metabolism
- Vitamin B6 degrades to pyridoxic acid which is renally excreted
III. Preparations: Food Sources
- Meat
- Poultry
- Fish
- Bananas
- Bran
- Nuts
- Whole-grain bread
- Cereals
- Soybeans
- Vegetables
IV. Causes: Vitamin B6 Deficiency
- Medication Causes of Vitamin B6 Deficiency
- Signs of Vitamin B6 Deficiency
- Glossitis
- Peripheral Neuropathy
- Dementia
- Niacin Deficiency
- Pyridoxine facilitates Tryptophan conversion to Niacin
- Pyridoxine deficiency may result in Niacin Deficiency
V. Efficacy: Potential benefit of Vitamin B6
- Effective in Hyperemesis
- May lower Coronary Artery Disease risk
- Based on retrospective studies
- Higher Vitamin B6 intake associated with lower Homocysteine
- Rimm (1998) JAMA 279:359 [PubMed]
VI. Resources
- Vitamin B6 (Harvard School of Public Health)
- Vitamin B6 (Wikipedia)