The human body needs vitamin B6 to metabolize tryptophan, produce serotonin and dopamine, use steroid hormones properly and manufacture nucleic acids. More than 100 enzymes are dependent on a vitamin B6 derivative, according to the Linus Pauling Institute at Oregon State University.
Humans do not produce their own vitamin B6, so they must get it from the foods they eat, reports the Linus Pauling Institute. This vitamin is found in salmon, avocados, fortified breakfast cereals, bananas, spinach, chicken and potatoes.
The human body does not store vitamin B6. Instead, it uses what it needs and excretes the excess in urine. Therefore, humans must keep eating foods rich in vitamin B6 to prevent deficiency, notes MedlinePlus. Vitamin B6 has several functions in addition to metabolizing tryptophan; producing neurotransmitters and nucleic acids; and helping the body use steroid hormones. This vitamin is essential for helping the nerves function, maintaining normal blood sugar levels, making antibodies to fight infection, breaking down proteins and producing hemoglobin.
It is possible to have too much or too little vitamin B6. Signs of a vitamin B6 deficiency include confusion; sores in the mouth and on the tongue; irritability; and depression, according to MedlinePlus. Too much B6 causes numbness, difficulty coordinating movements and sensory changes. Adults need anywhere from 1.2 to 1.7 micrograms of vitamin B6 per day depending on their age and gender.