One of the most common causes of vitamin B6 deficiency is alcohol abuse. Alcoholics usually have a poor diet, and alcohol increases the breakdown and loss of this vitamin in the body. Taking theophylline in children with asthma is also associated with a risk of vitamin B6 deficiency because it lowers vitamin B6 levels in the body.
Vitamin B, especially vitamin B6, should be obtained through diet or supplements. According to the University of Maryland Medical Center, vitamin B6 can be obtained from chicken, turkey, tuna, salmon, shrimp, milk and cheese. Also, plant sources of this vitamin include lentils, spinach, brown rice, sunflower seeds, white flour and carrots. Vitamin B6 is also found in multivitamins and vitamin B supplements.