Vitamin B6 (Pyridoxine)
What is Vitamin B6 (Pyridoxine)?
Vitamin B6, also known as pyridoxine, is a water-soluble vitamin and a member of the B vitamin family. It is important for neurotransmitters, cognitive development, and methylation.
Pyridoxal 5′-Phosphate (P-5-P) is the active form of vitamin B6. It may have metabolic benefits that may not be provided by other forms.
The function of B6 within its coenzyme forms varies greatly within the body, playing a part in over 100 different enzymatic reactions. [1]
Vitamin B6 also plays a significant role in the formation of neurotransmitters, affecting cognitive development, and controlling homocysteine levels in the blood. [1]
Vitamin B6 is an important nutrient for methylation, and should be considered for those with the MTHFR gene mutation.
There are a few small studies that showed varying results with supplementing with a combination of vitamin B6 and magnesium. More research needs to be done to verify this combination of supplements is beneficial. [2]
Food Sources of Vitamin B6
Recommended Daily Intake
These recommendations are based off of the Recommended Dietary Allowance (RDA), which is the average daily level of intake sufficient to meet the nutrient recommendations of nearly all (97-98%) of healthy individuals.
Males
o-6 months: 0.5 mg
7-12 months: 0.6 mg
1-3 years: 1 mg
4-8 years: 1.3 mg
9-13 years: 1.3 mg
14-18 years: 1.3 mg
19-50 years: 1.3 mg
51+ years: 1.7 mg
Females
o-6 months: 0.5 mg
7-12 months: 0.6 mg
1-3 years: 1 mg
4-8 years: 1.2 mg
9-13 years: 1.3 mg
14-18 years: 1.3 mg
19-50 years: 1.3 mg
51+ years: 1.5 mg
Deficiency
B6 is rarely an isolated deficiency and is often paired with other B-Vitamin deficiencies such as B12 and folate.
B6 Deficiency is Associated With:
Microcytic anemia
Electroencephalographic abnormalities
Dermatitis
Scaling of the lips and cracked corners on the mouth (cheilosis)
Swollen tongue (glossitis)
Depression
Confusion
Weakened immunity
Irritability, acute hearing, and convulsive seizures within infants with deficiency
Individuals at Higher Risk for B6 Deficiency Include:
Poor intake from restricted eating
Kidney diseases
Autoimmune disorders
Poor absorptions from conditions like celiac disease, Crohn’s disease and ulcerative colitis and inflammatory bowel disease
Alcohol dependency
Genetic diseases like homocystinuria
Individuals taking antiepileptic drugs over an extended amount of time
Toxicity
High intakes of B6 from food sources have not been linked to adverse health effects, but supplementation of high doses of B6 (1-6 g/d for 12-40 months) can cause progressive sensory neuropathy with ataxia (loss of control over movement). Symptoms from toxicity from supplements typically stop once the supplement has been stopped.
Other symptoms of excessive B6 intake include:
Painful dermatological lesions
Light sensitivity
Gastrointestinal issues such as nausea and heartburn
Some research shows birth defects in children when the mother was taking pyridoxine supplements in the first half of the pregnancy. Conflicting research has also been reported to see no association with pyridoxine supplementation in pregnant women and effects on the infants.
Upper limits have been established for B6 from both foods and supplements, but limited research has been done to solidify this recommendation. The Tolerable Upper Intake Level (UL): Maximum daily intake unlikely to cause adverse health effects.
Males & Females
0-12 months: 30 mg/day
1-3 years: 40 mg/day
4-8 years: 60 mg/day
9-13 years: 80 mg/day
14-18 years: 100 mg/day
19-50 years: 100 mg/day
Supplements
B6 is available as its own supplement as well as within a multivitamin or in a B-Complex supplement. The most common form you will see is pyridoxine (pyridoxine hydrochloride (HCl) or PLP). B6 supplements are available in chewable tablets and in liquid form. Absorption of supplements in the body is similar to the amount absorbed through foods (about 50% of what is taken in). Large doses, while absorbed well, are quickly excreted through urine.
Examples
Note: All supplements are linked to Amazon for convenience, however, buying supplements on Amazon does not guarantee quality, as there are many “unverified resellers” selling nutrition supplements. To buy supplements that are verified to be sent directly to the consumer, you can create an account on the Autism Dietitian FullScript and search for the respective supplement under “Catalog”.
DISCLAIMER: Before starting any supplement or medication, always consult with your healthcare provider to ensure it is a good fit for your child. Dosage can vary based on age, weight, gender, and current diet.
Vitamin B6 & Autism in the Research
B6 Intake and Deficiencies with Adverse Effects
Regular intake of B vitamins, such as B6, play an essential role in helping to maintain metabolic homeostasis (balance) within individuals with autism. [3]
B vitamin deficiencies are common within individuals with autism, and are linked to adverse health effects including disruption in intestinal bacteria, reduced absorption, and difficulty with metabolic processes. [4]
Individuals with autism are more likely to have inadequate intake and/or deficiencies in B vitamins, such as B6. [5-6]
B vitamin deficiencies have been linked to enhanced risk of behavioral and mood disorders, elevated levels of serum homocysteine, and heart disease. [6]
Supplementation
Treatment including B6 supplementation has been seen to be beneficial for individuals with autism. [6]
Vitamin B6 is beneficial for about half of autistic individuals in decreasing behavioral problems. [7]
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[1] Stover PJ, Field MS. Vitamin B-6. Adv Nutr. 2015;6(1):132-3.
[2] Nye C, Brice A. Combined vitamin B6-magnesium treatment in autism spectrum disorder. Cochrane Database Syst Rev. 2005;(4):CD003497.
[3] Kałużna-czaplińska J, Jóźwik-pruska J, Chirumbolo S, Bjørklund G. Tryptophan status in autism spectrum disorder and the influence of supplementation on its level. Metab Brain Dis. 2017;32(5):1585-1593.
[4] Belardo A, Gevi F, Zolla L. The concomitant lower concentrations of vitamins B6, B9 and B12 may cause methylation deficiency in autistic children. J Nutr Biochem. 2019;70:38-46.
[5] Barnhill K et al. Dietary status and nutrient intake of children with autism spectrum disorder: A case-control study. Research in Autism Spectrum Disorders. 2018;50:51-59.
[6] Bjørklund, G., Waly, M.I., Al-Farsi, Y. et al. The Role of Vitamins in Autism Spectrum Disorder: What Do We Know?. J Mol Neurosci 67, 373–387 (2019). https://doi.org/10.1007/s12031-018-1237-5
[7] Sato K. Why is vitamin B6 effective in alleviating the symptoms of autism?. Med Hypotheses. 2018;115:103-106.Sato
