Vitamin B6, also called pyridoxine, is one of 8 B vitamins. Vitamin B6 is a water-soluble vitamin.
 There are three different natural forms of vitamin B6, namely pyridoxine, pyridoxamine, and pyridoxal, all of which are normally present in foods. For human metabolism the active derivative of the vitamin, pyridoxal 5-phosphate (PLP), is of major importance as the metabolically active coenzyme form.

Functions
Make antibodies. Antibodies are needed to fight many diseases.
Maintain normal nerve function Make hemoglobin. Hemoglobin carries oxygen in the red blood cells to the tissues. A vitamin B6 deficiency can cause a form of anemia. Break down proteins. The more protein you eat, the more vitamin B6 you need.
Keep blood sugar (glucose) in normal ranges
It’s significant to protein, fat and carbohydrate metabolism and the creation of red blood cells and neurotransmitters .Your body cannot produce vitamin B6, so you must obtain it from foods or supplements.

Rich Foods
1) Wild Caught Tuna (fish) 3 oz: 0.87 mg (44% DV)
2) Banana 1 medium: 0.43 mg (21% DV)
3) Salmon 3 oz: 0.7 mg (35% DV)
4) Grass-fed Beef 3oz: 0.57 mg (30% DV)
5) Chicken breast 3 oz: 0.46 mg (23% DV)
6) Spinach (cooked) ½ cup: 0.22 mg (11% DV) 
7) Sweet potato ½ cup: 0.29 mg (15% DV)
8) Hazelnuts ½ cup: 0.38 mg (19% DV)
9) Turkey 3 oz: 0.691 mg (35% DV) 
10) Garlic 3 cloves: 0.11 mg (5 % DV)
etc..

Overdose

Over doses of vitamin B6 can cause:
Difficulty coordinating movement
Numbness
Sensory changes
Deficiency of this vitamin can cause:
Difficulty coordinating movement
Numbness
Sensory changes
Deficiency of this vitamin can cause:
Confusion
Depression
Irritability
Mouth and tongue sores (Vitamin B6 deficiency is not common in the United States.)

Deficiency 

Vitamin B6
Deficiency of vitamin B6 leads to Neurological symptoms like depression, irritability, nervousness, mental confusion, convulsions and peripheral neuropathy glossitis, depression, hallucinations, muscle pains.

SUMMARY

Vitamin B6 may prevent a decline in brain function by decreasing homocysteine levels that have been associated with Alzheimer’s disease and memory impairments. However, studies have not proven the effectiveness of B6 in improving brain health.