Vitamin B6, also known as pyridoxine, pyridoxal, and pyridoxamine, is one of eight vitamins part of the vitamin B complex.  Like our friend vitamin C, vitamin B6 is water soluble and, also like vitamin C, your body cannot produce B6, so it must come entirely from your diet. 

Vitamin B6 is involved in more than 100 metabolic reactions in the body, especially in the metabolism (processing) of amino acids (protein), carbohydrates and fats, as well as for normal functioning of the nervous system and red blood cells.

Vitamin B6 deficiency is rare, but certain factors may put people at risk.  Factors includes:

  • Alcohol abuse
  • Contraceptive medication
  • Age-related malabsorption
  • Autoimmune inflammatory disorders such as rheumatoid arthritis, 
  • Autoimmune intestinal disorders such as celiac disease, Crohn’s disease, ulcerative colitis, and inflammatory bowel disease.

Mild vitamin B6 deficiency causes biochemical changes in the body, however could show no signs or symptoms for months until the deficiency progresses.  

Signs of Vitamin B6 deficiency includes:

  • Anemia
  • Inflammation of the skin (dermatitis)
  • Seizures
  • Depression
  • Confusion
  • Weakened immune system
  • Cognitive decline
  • Irritability (especially in children)
  • Impaired alertness

Vitamin B6 is found in a variety of foods, such as:

  • Chickpeas
  • Beef liver
  • Poultry
  • Fish (tuna, salmon)
  • Legumes
  • Nuts
  • Banana
  • Potatoes

The majority of the vitamin B6 is highly bioavailable from a mixed diet. 

Vitamin B6 in the brain

The brain consumes the most energy in the whole body.  Vitamin B6 has a role in many different chemical reactions in the brain and it is a fair assumption that minor deficiency in Vitamin B6 may impact brain function.  Specific areas where vitamin B6 is required in the brain includes:

  1. Neurotransmitters synthesis
  2. Inactivation of homocysteine 
  3. Antioxidant defence
  4. Cognitive function in health aging adults

What does vitamin B6 do in the brain?

Vitamin B6 easily crosses the blood-brain barrier (BBB), to reach neuronal and glial cells, two cell types in the brain.

  • Biosynthesis of neurotransmitters
  • Vitamin B6 is the water-soluble vitamin that has the single biggest impact on neurotransmitter synthesis via amino acid metabolism.  Vitamin B6 is a cofactor for the amino acid glutamic acid, tyrosine, tryptophan, and histidine. These synthesisted the neurotransmitters GABA, dopamine, norepinephrine, serotonin and histamine, respectively.

    Vitamin-B6-biosynthesis-of-NT

    You can see from the figure above, Vitamin B6 is essential for the production of many of neurotransmitters involved in brain health: learning, cognition, mood, and memory

    In animal studies, B6 deficiency has been shown to lead to a decrease in GABA concentration in the brain. GABA is an inhibitory neurotransmitter, so when levels decrease,  this favours an increase in the excitatory neurotransmitter, glutamate.  Strong evidence suggests that changes in this GABA-Glutamate balance leads to sleep and mood problems, as well loss of proper stress control.  In other words, it becomes harder for your body to control sleep, mood and cortisol levels without proper levels of vitamin B6. 

    Despite a lack of severe deficiency, suboptimal amounts of vitamin B6 are relatively common in the population. 

  • Vitamin B6 and homocysteine
  • The amino acid called homocysteine is essential for normal cellular functions. However, higher levels of this amino acid, or the buildup per say, can trigger many diseases such as heart disease, strokes, cancer, and autoimmune diseases.  It’s also associated with lower mood and cognitive impairment

    Homocysteine is converted into other amino acids via one of two pathways: 

    • where homocysteine is converted to the amino acid methionine through folate (B9), and vitamin B12, 
    • or vitamin B6 that converts homocysteine into the amino acid cysteine. 

    Many factors can raise the levels of homocysteine, such as poor diet and lifestyle choices. However, one of the most prominent causes is deficiency in either folate and vitamin B12 or vitamin B6.  Growing evidence shows that vitamin B supplements like B6 can bring homocysteine levels back within a normal and healthy range. 

  • Vitamin B6 and antioxidant defence
  • Vitamin B6 may have a crucial role in your body's antioxidant defence system.  Your body uses antioxidants for a wide range of functions, including healthy immune function and metabolism.  Although, the exact mechanism on how vitamin B6 protects the cell from damage is unclear, scientists have two main theories

    • Similar to vitamin C, vitamin B6 could inactivate reactive oxygen species (ROS), learn more about ROS and antioxidant defence in our vitamin C blog.  
    • Another possibility is that vitamin B6 is a co-factor in the glutathione antioxidant defence system.  Glutathione is a small protein that is known as the master antioxidant.  It protects the cells against toxins, and free radicals like ROS. 

    In both human and animal models, low blood levels of Vitamin B6 are associated with an increase in oxidative damage biomarkers. These findings support the relationship between lower vitamin B6 status and higher oxidative stress. Getting adequate amounts of vitamin B6 from your diet or through supplements has protective effects

    Although the mechanism on how vitamin B6 protects the cell is still unclear, there is strong evidence that vitamin B6 is critical to protect the cells from damage. 

  • Cognitive function in healthy aging adults
  • There is no getting past it, getting older is associated with a decline in cognitive performance. Interestingly, a research group from Ireland, found that  levels of vitamin B6 are a predictor of cognitive decline in an aging population. 

    Similar to what is observed with vitamin C, suboptimal levels of vitamin B6 are associated with a faster rate of cognitive decline over a 4-year period. 

    What’s interesting about this research article is that the finding is specific to Vitamin B6.  The researcher did not find any link between cognitive decline and the other B vitamins.  This means the B6 specifically is crucial for healthy aging and the authors go on to suggest that B6 could be an important protective factor in cognitive health. 

    middle-age-man-running

    Vitamin B6, sleep and stress

    Similar to magnesium, vitamin B6 has been proposed as a anti-stress therapy, because it is important in making neurotransmitters that affect depression, and anxiety (GABA, dopamine, serotonin), and can help to balance off cortisol, aka “the stress hormone”, release. The relationship between low magnesium levels and greater perceived stress have been well documented.  Check out the magnesium blog for more details.  In cases of low magnesium serum level, magnesium supplementation improves sleep, and cortisol levels.  So how are magnesium and B6 linked? It is believed that vitamin B6 facilitates magnesium absorption.   Magnesium can alleviate stress symptoms, however, in combination with vitamin B6 may provide faster relief in magnesium-deficient animals.  In a human study, a combination of magnesium and vitamin B6 provides faster relief in people with severe stress over magnesium supplementation alone. 

    On a fun side note, evidence suggests that vitamin B6 can trigger lucid dreaming. There is a whole field of study dedicated to investigating the benefits and relationship of lucid dreaming and health.  Dream recall and lucid dreaming has many benefits such as alleviating nightmares, promoting creative problem solving, and exploring the mind-body relationship and consciousness. 

    Vitamin B6 dose and side effects

    Pyridoxal 5’-phosphate is the active form of vitamin B6, and is mainly involved in metabolism of amino acids.  It is important to note that pyridoxal 5’-phosphate has not been associated with toxicity, however its inactive form, found in many multi-vitamins and supplements, pyridoxine, has reported toxicity and neuropathy at high doses. 

    Vitamin B6 (pyridoxal 5’-phosphate) supplementation dose ranges from 0.1-100 mg/day with a maximal dose of 100 mg/day based on recommendations.

    Vitamin B6 in MindGain

    Vitamin B6 is essential to many functions in the body, mostly concerning amino acid metabolism. 

    MindGain uses the active and highly bioavailable form of vitamin B6, pyridoxal 5’-phosphate for these reasons: 

    • Vitamin B6 must come from your diet
    • It is safe, effective, and highly bioavailable
    • It is required for the synthesis of neurotransmitters such as GABA, dopamine, norepinephrine, and serotonin
      • These neurotransmitters are crucial for cognition, learning, memory and mood. 
    • It may provide stress relief especially in combination with magnesium
      • Evidence suggest it promotes quality sleep
    • It can lower homocysteine levels

    Everyone needs vitamin B6

    Your body doesn’t make vitamin B6, so it is really important to get an adequate amount in your diet.  It is widely accepted that vitamin B6 is necessary for optimal health.  When it comes to supplementation, pyridoxal 5’-phosphate is an excellent supplement to support brain health and promote cognitive performance.

     

     

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