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Vitamin B6 101

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Vitamin B6 101

Vitamin B6 is required for over 100 different reactions in the body, making it an important vitamin. Unfortunately, it’s estimated that 13% of Americans may be deficient in vitamin B6. This article will discuss what vitamin B6 is, including its role in the body and deficiency causes and symptoms. We’ll then discuss how to test for vitamin B6 and how to ensure you’re getting enough in your diet.


What is Vitamin B6?

Vitamin B6 is an umbrella term for six related compounds: pyridoxine, pyridoxine 5’-phosphate pyridoxal, pyridoxal 5’-phosphate (PLP), pyridoxamine, and pyridoxamine 5’-phosphate (PMP). Vitamin B6 is not naturally produced in the body, and thus dietary sources are required.

Vitamin B6’s Role in The Body

The most used of the six forms of vitamin B6 is PLP, which is used in over 4% of all enzymatic reactions. Vitamin B6 is involved in the function of the nervous system, hemoglobin creation and function, metabolism of the amino acid tryptophan, sex hormone function, and formation of nucleic acids, a class of molecules including DNA.

Nervous System

Neurotransmitters are chemicals that aid in the communication between brain cells called neurons. Neurons also use them to communicate and send signals to other areas of the body. PLP is explicitly required to form the following neurotransmitters: serotonin, dopamine, glycine, d-serine, glutamate, histamine, and GABA.


Hemoglobin is a protein found in red blood cells that carries oxygen. Vitamin B6 affects hemoglobin in a couple of different ways. First, PLP is required to synthesize the “heme” portion of hemoglobin, which contains iron. Second, PLP and pyridoxal can affect how hemoglobin picks up and releases oxygen by binding to hemoglobin.


Tryptophan is an amino acid involved in creating the active form of niacin called nicotinamide adenine dinucleotide (NAD). NAD affects many processes in the body, including immune and inflammatory functions. PLP is required for the creation of NAD by tryptophan.

Nucleic Acids

PLP is necessary for a step in methylation, a process in the body that influences detoxification processes, hormone breakdown, neurotransmitter synthesis, and, most pertinent to this article, DNA synthesis. The product of the reaction that PLP is involved in will then be used to create nucleic acids, including DNA and RNA.

What Causes B6 Deficiency?

B6 deficiency is often seen concurrently with other b-vitamin deficiencies, including B12 and folate. The following conditions will increase the risk for a vitamin B6 deficiency: autoimmune disorders, including rheumatoid arthritis, Celiac disease, Crohn’s disease, and ulcerative colitis; people with alcohol dependence; those with impaired renal functioning, including chronic renal insufficiency and end-stage renal disease.

B6 Deficiency Symptoms Include

  • Swollen tongue (glossitis)
  • Scaling of the lips and cracking of the corners of the mouth (dermatitis with cheilosis)
  • Depression
  • Confusion
  • Anemia
  • Abnormal electroencephalographic (EEG) findings (EEG is a test to assess the electrical activity of the brain)
  • Poor immune function

B6 deficiency presents with different symptoms in infants, including hearing problems, seizures, and irritability.

How to Test Vitamin B6 Levels

Access Medical Laboratories offers a single-marker vitamin B6 test, where B6 values are considered normal when they are between 5-50 micrograms/liter (mcg/L). Vitamin B6 levels can also be found on micronutrient tests such as the Micronutrient Test by SpectraCell Laboratories.

Additionally, levels of vitamin B6 can be indirectly measured by assessing the breakdown products of tryptophan. Vitamin B6 may also be measured in the urine.


How to Get Enough Vitamin B6 from Your Diet

The Institute of Medicine at the National Academies formed a Food and Nutrition Board that created Dietary Reference Intakes (DRIs) for vitamins and minerals. One DRI is the Recommended Daily Allowance (RDA), defined as the average daily amount of a vitamin or mineral needed to achieve nutritional adequacy in almost all healthy populations. When insufficient evidence is present to form an RDA, an Adequate Intake (AI) level is formed. AIs are levels assumed to reach nutritional adequacy.

RDAs for Vitamin B6

Pregnant and lactating women have differing RDAs from their respective female age RDAs due to their unique nutritional requirements. Pregnant women aged 14-50 have an RDA of 1.9mg, and lactating women aged 14-50 have an RDA of 2.0 mg.

Infants under the age of one are given AIs for vitamin B6. The AI for birth to six-month-old males and females is 0.1 mg, and from seven to 12 months is 0.3 mg.

Sources of vitamin B6 include food and supplements.

Food Sources of Vitamin B6

Vitamin B6 Supplements

Vitamin B6 is found in multivitamins and B-complexes and is also sold as a stand-alone supplement. Most vitamin B6-containing supplements will be in the form of pyridoxine, although some do contain PLP. Forms of supplements include liquid, tablets, capsules, and lozenges. The absorption of vitamin B6 from supplements is similar to vitamin B6 found in foods.



Vitamin B6 is an important vitamin, required for many reactions in the body involving the creation of neurotransmitters, NAD, and DNA, and oxygen circulation in the body. Vitamin B6 deficiency can result in serious symptoms, including abnormal brain activity. Testing vitamin B6 levels can ensure proper levels in the body. Knowing food and supplement sources of vitamin B6 can be beneficial to ensure adequate levels and prevent deficiencies.

The information provided is not intended to be a substitute for professional medical advice. Always consult with your doctor or other qualified healthcare provider before taking any dietary supplement or making any changes to your diet or exercise routine.
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