Vitamin B12 (Cobalamin)
What is Vitamin B12 (Cobalamin)?
Vitamin B12 is a water-soluble B vitamin that is vital for red blood cells, neurologic function, and the formation of DNA. Research shows that individuals with autism frequently have low levels of B12, which may be caused by methylation issues or low stomach acid.
Supplementation of the correct form of B12 can help methylation and help maintain metabolic balance.
Vitamin B12 is also called “cobalamin”, since B12 contains the mineral cobalt.
Vitamin B12 can be found in various forms, some active and some inactive. The prefix of the form will tell you which form it is in (i.e. methyl-cobalamin, cyano-cobalamin, etc). Methylcobalamin, adenosylcobalamin, and hydroxycobalmin are forms that are active within human metabolism, while cyanocobalamin has to be activated (or methylated) to be able to be used in the body.
B12 is needed for red blood cell (RBC) formation, neurologic function, and the formation of DNA. B12 plays an important role in the methylation cycle.
B12 must come in contact with hydrochloric acid (HCl, aka stomach acid) and attach to Intrinsic Factor in order to be absorbed. For people with low stomach acid (due to gastrointestinal issues, H. pylori, pernicious anemia, or old age), B12 may not be absorbed well. Left untreated, this could lead to megaloblastic anemia and neurologic disorders.
B vitamin deficiencies, particularly vitamin B12, 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. [1-3]
Regular intake of B vitamins, such as B12, play an essential role in helping to maintain metabolic homeostasis (balance) within individuals with autism. [4]
Food Sources of Vitamin B12
B12 can only be found naturally within animal products. B12 cannot be found in fruit, vegetable or grain products unless it has been added (ex: fortified breakfast cereals). Fortified plant foods is a good option for those who follow a low animal product diet like vegetarians or vegans. Some Nutritional Yeast contains B12, though it is in the inactive cyanocobalamin form.
Meats
Poultry
Seafood
Liver
Eggs
Recommended 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 & Females
o-6 months: 0.4 mcg/d
7-12 months: 0.5 mcg/d
1-3 years: 0.9 mcg/d
4-8 years: 1.2 mcg/d
9-13 years: 1.8 mcg/d
14-18 years: 2.4 mcg/d
19-50 years: 2.4 mcg/d
Pregnancy: 2.6 mcg
Lactation: 2.8 mcg
51+ years: 2.4 mcg/d
Deficiency
Signs of B12 deficiency include:
Megaloblastic anemia
Fatigue
Weakness
Constipation
Loss of appetite
Weight loss
Neurological changes such as tingling in hands/feet
Balance issues
Depression
Confusion
Dementia
Poor memory
Sores on mouth or tongue
Failure to thrive, movement disorders and developmental delays in infants.
Treatment for deficiency is typically B12 supplementation. Large amounts of folate (Vitamin B9) could disguise a B12 deficiency by helping to treat megaloblastic anemia, but does not help the neurologic disorders that may occur due to B12 deficiency. Permanent nerve damage could occur if B12 deficiency is not treated.
Groups at increased risk of B12 deficiency:
Individuals with restricted diets and poor intake of foods such as animal products
Vegans and Vegetarians
Older adults
Pernicious anemia
Gastrointestinal disorders such as celiac disease and Crohn’s disease
Surgery of the gastrointestinal tract, especially the stomach and small intestine
Pregnant and lactating women who follow restricted animal product diet
Individuals with low stomach acid (hypochlorhydria)
Toxicity
An upper limit for B12 has not been established because no adverse effects have been recorded to this date.
Supplements
B12 is most commonly seen in supplements in the form of cyanocobalamin, which the body will then convert into methylcobalamin and 5-deoxyadenosylcobalamin. For those with the MTHFR mutation or who have issues with methylation, it’s recommended to take B12 in the methylcobalamin, adenosylcobalamin, or hydroxocobalamin forms.
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”.
B12 Injections
B12 can also be given by intramuscular injection by a doctor. The form of B12 used for this is typically cyanocobalamin, methylcobalamin, or hydroxocobalamin. For individuals with autism and/or methylation issues, it’s recommended to use methylcobalamin or hydroxocobalamin instead of cyanocobalamin. This method is typically used for those who have poor absorption capabilities, such as those with low intrinsic factor levels, since it bypasses digestion and goes straight to the bloodstream.
B12 can also be seen as a nasal gel or spray. This method is effective at raising blood B12 levels, but more research still needs to be done in this area.
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 B12 & Autism in the Research
B12 Levels in Autism
Low B12 serum levels (paired with low B9 levels) is associated with ASD. [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. [1-2]
B vitamin deficiencies have been linked to enhanced risk of behavioral and mood disorders, elevated levels of serum homocysteine, and heart disease. [5]
Supplementation
Supplementation of B12 could improve methylation capacity in children with autism. [5-6]
Regular intake of B vitamins, such as B12, play an essential role in helping to maintain metabolic homeostasis (balance) within individuals with autism. [4]
Maternal B12 Intake
Excess B12 intake during pregnancy is linked to increased risk of autism in the offspring. Risk was highest in the research if mother had excess folate and B12. More research needs to be done in this area. [7]
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[1] 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.
[2] Zhang Y, Hodgson NW, Trivedi MS, et al. Decreased Brain Levels of Vitamin B12 in Aging, Autism and Schizophrenia. PLoS ONE. 2016;11(1):e0146797.
[3] Mahruba, S., Begum, S., Shahjadi, S., Afroz, S., Siddiqi, U., & Parvin, J. (2020). Serum vitamin B12 and folic acid status in Autism spectrum disorder children. Journal of Bangladesh Society of Physiologist, 14(2), 43-47. https://doi.org/10.3329/jbsp.v14i2.44783
[4] 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):1585-93.
[5] 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
[6] Hendren RL, James SJ, Widjaja F, Lawton B, Rosenblatt A, Bent S. Randomized, Placebo-Controlled Trial of Methyl B12 for Children with Autism. J Child Adolesc Psychopharmacol. 2016;26(9):774-83.
[7] Raghavan R, Riley AW, Volk H, et al. Maternal Multivitamin Intake, Plasma Folate and Vitamin B12 Levels and Autism Spectrum Disorder Risk in Offspring. Paediatr Perinat Epidemiol. 2018;32(1):100-11.
