The deficit of the vitamin B6 is rare. However, isoniazid (anti-TB drug, which is widely used), can cause isolated deficits of pyridoxine. In this case vitamin B6 is bonded to the drug and rapidly excreted in the urine.
There is also some evidence that the failure of kidney inhibits pyridoxal kinase deficiency of coenzyme pyridoxal phosphate occurs, despite sufficient quantities of vitamin B6 are intaken.
Vitamin B6 deficiency can cause anemia, nervous disorders and various skin problems.
This vitamin is especially important for pregnant women, and also facilitates premenstrual symptoms.
Some research suggest that this vitamin could also be used in anti-tumor therapy. However, the most important role of vitamin B6 is its role in the immune system. In fact, this vitamin is the most important vitamin of B-group vitamins for development of the immune system.
In the absence of vitamin B6 processes of transamination are disturbed and also other pathways of protein metabolism and tissue respiration. In vitamin B6 deficiency disease a change of function of the nervous system occur.
Since the creation of nicotinic acid (niacin) depends on pyridoxal phosphate, the pellagra frequently occur in companion with deficits of pyridoxine (as well as niacin).
(Image taken from moondragon.org)
The changes that occur due to niacin and vitamin B6 deficiency
A large number of genetic diseases caused by the inability of specific apoenzymes (inactive enzyme that need to bind a cofactor or coenzyme in order to be activated) to bind pyridoxal phosphate in adequate stiffness.
Overdose (hypervitaminosis, intoxication)
Vitamin B6 can be toxic if it intake in high doses and then can cause serious neurological disorders. This has been observed in people who consume more than 2 grams of vitamin a day.
Symptoms, which can occur with increased intake of this vitamin are: unsteady gait, stiffness in the feet followed by the cumbrous hands and nighttime restlessness.
The most common reason for the increase of vitamin B6 in the body is its use against premenstrual syndrome, so the increased intake of vitamin B6 is not recommended without prior consulting a doctor.
This vitamin can, even when moderate ingested, reduce the effect of drugs used in patients with Parkinson's disease.