Vitamin B12 deficiency is usually the result of poor intestinal absorption due to GI surgeries and/or GI disorders, or inadequate dietary intake, such as vegetarian or vegan diet, which restrict animal products.

Vegans, people who do not eat any animal products including eggs and dairy, are more likely to develop B12 deficiency because of their restrictive diets. Ovo-lacto-vegetarians usually consume enough B12 through eggs and dairy products. Vegans obtain their B12 from dietary supplements and/or fortified foods, such as fortified breakfast cereals, fortified soy products, fortified energy bars, and Brewer’s yeast.

Occasionally, certain medication may increase its metabolism in the body.

Deficiencies in vitamin B12 and folate levels cause changes in homocysteine level, which might be related with depression, mood disorders, psychotic disorders, an obsessive-compulsive disorder.

Recently, some studies have reported deficiencies in vitamins B12 and folate (vitamin B9) in patients diagnosed with ASD and ADHD as well as beneficial effects of those vitamins for some of the associated ASD and ADHD symptoms.

B-12 deficiency causes symptoms affecting your nerves (numbness, tingling, tremors, balance problems) and your mind (depression, brain fog, memory loss, mood swings, and, in rare cases, dementia, hallucinations and psychosis).

Taking folic acid (folate) or eating a lot of folate-containing foods without adding B-12 can actually mask the symptoms of a developing B-12 deficiency. Although folate will keep your blood count normal even if your B-12 is falling, the folate will not protect your brain and nervous system. Your symptoms of numbness, tingling, balance problems, and emotional issues will continue unchecked.

Vitamin B12 (B12) is a water-soluble vitamin with key role in normal functioning of the brain, nervous system, and formation of blood cells. It is involves in DNA synthesis and regulation, and also fatty acid synthesis and energy production.

B12 helps with ADHD symptoms through its involvement in many of the brain functions, especially in the production and maintenance of the myelin sheath (the protective coating on nerve cells), essential fatty acid metabolism and energy production. The myelin sheath is like the plastic casing on electrical wires. These myelin sheath serve the same purpose.

The effect of vitamin B12 on mood is not yet fully understood. However, this vitamin plays a vital role in synthesizing and metabolizing serotonin, a chemical responsible for regulating mood.

Therefore, vitamin B12 deficiency may lead to decreased serotonin production, which may cause a depressed mood.

Supplement with methylcobalamine works in several mechanism.

Methylcobalamin is a cofactor of methionine synthase, which catalyzes the conversion of homocysteine to methionine. Our body can also obtain methionine through diet. Our body needs methionine to make S-adenosyl-methionine (SAMe), which is needed for methylation of myelin sheath phospholipids. Methylation is the transfer of the “methyl” group. Methycobalamin provides the methyl group for the transfer. That is how methylcobalamin is involved here.

Although our body does not need B12 to make SAMe, methionine synthase helps to provide additional methionine to boost SAMe production. SAMe is also involved in the production of certain neurotransmitters and catecholamines, which help with mood.

Methylcobalamin works with the folic acid biochemical pathway. A precursor folic acid molecule must interact with the enzyme MTHFR (methylenetetrahydrofolic acid) to become 5-methyltetrahydrofolic acid, the molecule that donates its methyl group to B12 so it can become methylcobalamin. Unfortunately, many children have a defect in this enzyme.

All of the B vitamins work together synergistically to support critical functions in the brain. All of the B-complex vitamins are co-factors to each other – that is, they help each other to be absorbed and utilized properly by the body. 

In studies, B-complex vitamins have been shown to reduce hyperactivity symptoms and increase serotonin in children with ADHD, resulting in calmer, happier children. And children taking methylcobalamine showed increased executive function. 

Preliminary studies suggest that vitamin and micronutrient supplements may reduce emotional liability, aggression and oppositional behaviors in children with ADHD and ASD. Studies also support the use of vitamin B12 supplements for improving symptoms of depression in people deficient in this vitamin.

Vitamin B12 supplementation may also help improve sleeping better likely due to the fact that methylcobalamine improves the body’s supply of melatonin.

Neither plants nor animals can produce vitamin B12. Only bacteria have the enzymes required for its synthesis. Animals are good sources of B12 is because of the bacteria living in the intestines, which makes the vitamin.

Vitamin B12 is found in any foods that come from animals, such as fish and shellfish, meat (especially liver, where the vitamin is stored), poultry, eggs, dairy products. The body absorbs B12 from animal sources better.

Plant foods are not considered to be reliable sources of B12.

Vitamin B12 rich food includes animal products, such as meat, poultry, seafood, dairy, and eggs, with eggs having the least.

Because all animals store B-12 in their livers, eating liver is an excellent (though not particularly popular) treatment for B-12 deficiency.

The general recommendation of B12 is between 0.4 to 2.4 mcg (micrograms) daily depending on age. Generally, for the purpose of treating ADHD, you may start with 1,000 mcg and go up to 2,500mcg per day. Toxicity is rare since Vitamin B12 is water-soluble, which means our body can easily get rid of the extra.

And since people with low vitamin B12 are likely to also have gastrointestinal symptoms that interfere with B-12 absorption, the best way to quickly increase (and maintain) B-12 levels are with B-12 injections, chewable tablets, or the recently released nasal sprays and skin patches.

There are several forms of vitamin B12 – cyanocobalamin is the synthetic form, and methylcobalamin and adenosylcobalamin are the physiological or active form. Cyanocobalamin does not occur in nature. It is commonly found in supplements due to its stability and cheaper cost of manufacturing. Theoretically, cyanocobalamine is readily converted to the active forms, methylcobalamin and/or adenosylcobalamin in the body.

Cyanocobalamin is the most common form of B12 found in supplements. It contains about 2% of cyanide or 20 micrograms of cyanide in a 1 mg cyanocobalamin tab. This amount may seem minute. However, children with ADHD, as you have read so far, have an inefficient detoxification system. Even a minute amount of cyanide may accumulate over time, causing neural damages.

One of the functions of B12 is methyl donation. Supplementation with cyanocobalamin would not serve this purpose. In fact, it would need a donation of the methyl group in the body to be converted to the active form.

Sublingual and spray methylcobalamin are supposedly much easier to absorb because these routes bypass the intestines, which can be an issue for people with GI problems.

Methylcobalamin is the active form, which means the body can put it to use right away without any further conversion. Besides, children with ADHD just seem to have very different metabolic requirements.

Methylcobalamin supplements are usually more expensive and available mainly in health food stores. Despite the cost and probably a little extra drive for some, it is still a better choice not only because it is active, but it is also a “cleaner” form. The methylcobalamin supplement you find in health food stores usually is free of additives, preservatives, artificial colorings, artificial sweeteners, etc. So you are definitely paying for quality for your money.

Ok, there you have it…

I hope you find this information helpful. Let me know what you think and comment below.

Remember ADHD does not doom your child to a life of under-achievement. You know your child is bright, full of potential, and deserves the best. In fact, many of the world’s greatest discoveries and inventions were made by people with ADHD.

Yektaş Ç, Alpay M, Tufan AE. Comparison of serum B12, folate and homocysteine concentrations in children with autism spectrum disorder or attention deficit hyperactivity disorder and healthy controls. Neuropsychiatr Dis Treat. 2019;15:2213-2219. Published 2019 Aug 6. doi:10.2147/NDT.S212361

Bala KA, Doğan M, Kaba S, Mutluer T, Aslan O, Doğan SZ. Hormone disorder and vitamin deficiency in attention deficit hyperactivity disorder (ADHD) and autism spectrum disorders (ASDs). J Pediatr Endocrinol Metab. 2016;29(9):1077-1082. doi:10.1515/jpem-2015-0473