Vitamin B12 Deficiency



Vitamin B12 deficiency and autism

There is increasing evidence to suggest that a combined deficiency of vitamin D and Vitamin B12 of the foetus is responsible for the development of autism in the neonate. It is already well established that vitamin B12 is necessary for development of the foetus and neonate. Developmental delay is a known consequence of vitamin B12 deficiency in addition, babies of mothers who are deficient in vitamin B12 may have lower cognitive scores one year after birth, even if the deficiency is detected, and low serum levels of vitamin B12 in the neonate have been linked to negative impacts on cognitive function, as well as motor and growth outcomes in the developing neonate. Further there is evidence of decreased levels of vitamin B12 seen in the brains of children with Autism (1), and also the association of vitamin B12 deficiency and developmental delay and adverse neurological outcomes in the neonate (2-6).


Critically, loading of the brain of the child occurs primarily in the foetus and up to 17% of vitamin B12 that crosses the placenta goes to the brain of the developing foetus. Brain loading with vitamin B12 (and selenium) is maximal in the final stages of development and as such babies that are born prematurely (commonly seen in children who develop autism) would have lower brain levels of vitamin B12.


Studies have shown that during pregnancy there is a significant drop in the level of vitamin B12 in the serum of the mothers, which progressively drops further during the course of the pregnancy and while the mothers are breast-feeding. Overt vitamin B12 deficiency may occur in pregnant women who have lower levels of vitamin B12 at the start of their pregnancy, or who are vegetarian or vegan, have Crohn of coeliac disease, who are on Metformin™ for diabetes, or who have undergone gastric bypass surgery. More recently it has been shown that functional vitamin B12 deficiency may also be present in women who are obese. Children born to mothers who have had weight loss bariatric surgery are more likely to be premature, a co-contributing factor to giving birth to a child who develops autism.


Studies on the metabolism of over 250 children with autism showed that they were all functionally deficient in vitamin B12. Accompanying the deficiency in vitamin B12, the children were all functionally deficient in vitamin B2. Hair metals analysis showed them to also be deficient in Iodine (~50%), Selenium (~80%) and Molybdenum (~50%). Deficiency in any of Iodine, Selenium and/or Molybdenum can all result in functional vitamin B2 deficiency, which in turn gives rise to functional B12 deficiency. Given that functional vitamin B2 deficiency is also associated with the development of obesity and subsequent gestational diabetes, there is good reason to believe that the mothers of the children with autism were more likely to be functionally deficient in vitamin B2 at time of pregnancy. Such deficiency would in turn result in functional vitamin B12 deficiency.


Other signs of vitamin B12 deficiency in the neonate include megalobastic anaemia, feeding difficulties (difficulties in suckling), developmental delay, microcephaly, hyptonia, lethargy, irritability, involuntary movements, seizures and cerebral atrophy" (Benbir etal, 2007).


Further Information on the role of vitamin B12 deficiency in autism


Further information on the biochemistry of autism can be found at




Zhang etal, 2016 Decreased levels of vitamin B12 in aging, autism and schizophrenia. PMID: 26799654

Whiton etal, 1979 Brain damage in infancy and dietary B12 deficiency PMID 502936

Smolka etal, 2001 Metabolic complications and neurological manifestations of vitamin B12 deficiency in children of vegetarian mothers. PMID 11787236

Zengin etal, 2008 Clinical manifestations of infants with nutritional vitamin B deficiency due to maternal dietary deficiency PMID 18945280

Halicioglu etal, 2011 Nutritional deficiency in infants of vitamin B12 deficient mothers PMID 99429203

Bravo etal, 2014 Haematological and neurological compromise due to vitamin B12 deficient in infant of a vegetarian mother.... PMID 25697251

Chu etal, 2016 Effects of melatonin and its analogues on neural stem cells. PMID  26499359

Rudnitskaya etal, 2015 Melatonin Attenuates Memory Impairment, Amyloid-β Accumulation, and Neurodegeneration in a Rat Model of Sporadic Alzheimer's Disease. PMID 26402759

Shen etal, 2016 Effect of Melatonin and Resveratrol against Memory Impairment and Hippocampal Damage in a Rat Model of Vascular Dementia.  PMID 28419991

Li etal, 2017 Effect of Melatonin on renewal of chick small intestinal mucosa PMID 28431176

Demir etal, 2013 Clinical and neurological findings of severe vitamin B12 deficiency... PMID 23781950

Strand etal, Maternal and infant vitamin B12 status during infancy predict linear growth at 5 yrs, Ped Res 2018

Smith, AD 2018 Maternal and infant vitamin B12 status and development. Ped Res.

Hare etal, 2013 A delicate balance: Iron metabolism and diseases of the brain... PMIC 3715022

Guevara-Campos etal, 2015 Autism and intellectual disability associated with mitochondrial disease and hyperlactacidemia.. PMID 25679448

Bravo etal, 2014 Haematological and neurological compromise due to vitamin B12 deficient in infant of a vegetarian mother.... PMID 25697251

Schroder etal 2017 Pregnant women of South Asian Ethnicity in Canada have substantially lower vitamin B12 status compared with pregnant woemen of European ethnicity PMID 28920568

Chandyo etal, 2017 The effects of vitamin B12 supplementation during pregnancy PMID 28851784

Woods etal, 1960 Vitamin B12Co-60 readily passes the placenta into fetal organs and nursing provides B12 from mother to pup... PMC 2137236

Benbir etal, 2007 Seizures during treatment of vitamin B12 deficiency. Seizure. 2007 Jan;16(1):69-73. Epub 2006 Dec 5.



Copyright © 2018 All Rights Reserved. 
The statements on this site compose a compendium of generally recognized signs of vitamin B12 deficiency, and problems that can then ensue They also are formulated from a summary of relevant scientific publications. In addition they may contain some forward looking statements of a general nature.
Reproduction in whole or in part in any form or medium without express written permission is prohibited