Vitamin B12 Deficiency in Children: Symptoms, Diagnosis and Prevention by Dr. Stalin Ramprakash

10 min read

Written by Dr. Stalin Ramprakash

Dr. Stalin Ramprakash

Dr. Stalin Ramprakash is an experienced and dynamic consultant who provides high-quality comprehensive care for children with cancer and blood-related problems. He completed his paediatric training More

Vitamin B12 Deficiency in children

The term “Vitamin B12” refers to a group of substances that are chemically related. These substances are grouped together because they all contain a rare metallic element called Cobalt. That’s why Vitamin B12 is also called “cobalamin.” B12 is the most complex vitamin of all. It is water-soluble, and it facilitates the production of blood cells. Vitamin B12 is also key for the healthy functioning of the nervous system.  Different age groups need different amounts of Vitamin B12. Most food sources of animal origin such as liver, meat, fish and dairy products provide sufficient amounts of B12 but it is not found in fruits, vegetables and cereals.

Our bodies cannot naturally produce vitamin B12. Certain groups are at risk of Vitamin B12 deficiency if they don’t have access to the right food sources. Pregnant women and lactating women require higher amounts of Vitamin B12. That’s because their foetuses or their babies need the extra B12 intake. When pregnant women, lactating women, or children don’t consume enough Vitamin B12, they can suffer from anaemia. Long-term Vitamin B12 deficiency can also pose serious health issues for children, including nerve damage and stunted development. Here’s the complete guide to Vitamin B12 deficiency in children.

In This Article

Vitamin B12 Deficiency in Children

A child with Vitamin B12 deficiency doesn’t receive sufficient amounts of this vital vitamin. Children’s bodies need Vitamin B12 to produce new red blood cells (RBCs). RBCs distribute oxygen to different body parts. That’s why children with Vitamin B12 deficiency suffer from anaemia.

RBC deficiency also makes them feel weak, tired, and dreary all the time. The improper distribution of oxygen that comes with Vitamin B12 deficiency can cause serious damage to a child’s nerves. It can even impact the development of their bodies and cause memory problems.

Here are some other possible effects of long-term Vitamin B12 deficiency in young children:

  • Developmental delay
  • Hypotonia
  • Tremors
  • Seizures
  • Failure to focus in school
  • Reduced IQ
  • Mental retardation
  • Slurred speech
  • Delayed language and social development (manifested as behavioural issues)
  • Gross motor movement issues
  • Brain atrophy

If Vitamin B12 deficiency is diagnosed late, children can suffer from permanent cognitive and intellectual disabilities.

Causes of Vitamin B12 Deficiency in Children

cause of B12 deficiency

Vitamin B12 deficiency in very young children is more commonly associated with defective absorption of the vitamin due to dietary deficiency or mother being deficient in breastfed babies. Poor absorption of the vitamin itself may also be a cause. Let’s explore the high-risk groups for Vitamin B12 deficiency in children:

1. Children with Mothers Who Have Vitamin B12 Deficiency

Babies born to mothers with Vitamin B12 deficiency are at high risk of developing the same condition. The babies may manifest the symptoms first when the mother looks well as babies are growing very fast and hence the demand is high. The main reasons why infants are born with Vitamin B12 deficiency include:

  • The pregnant mother is a vegetarian
  • The mother suffers from pernicious anaemia which is an autoimmune condition leading to poor absorption of Vitamin B12 from the gut.
  • The mother has celiac disease
  • Mothers who use nitrous oxide during labor, if they are already deficient
  • The mother has Crohn’s disease
  • The mother has eating disorders
  • The use of prolonged proton-pump inhibitors for more than 2 years increases the risk

Children who are only breastfed in the first year of their lives may not receive sufficient amounts of Vitamin B12. Their mothers’ bodies may not have optimum amounts of this vitamin in storage. Generally, breast milk alone is sufficient for all the nutritional needs of the baby for the first 6 months. Weaning must start no later than 6 months to keep up with the nutritional demands of the baby.  However, the amount of Vitamin B12 in the formula may not be sufficient to amend their deficiency.

Existing deficiencies in children become worse when their deficient mothers breastfeed them. That’s why mothers with unidentified Vitamin B12 deficiency are highly likely to pass on this condition to their children.

[Read : What Are the Benefits of Eggs For Children?]

2. Children with Low Vitamin B12 Intake

Most children get more than enough Vitamin B12 from consuming milk, eggs, cheese, and meat. This vitamin is absorbed via their digestive systems (stomachs and intestines). Children who are likely to not consume enough amounts of Vitamin B12 are:

a) Vegetarian Children

If B12-rich animal foods are not part of a child’s diet, they may develop Vitamin B12 deficiency especially if the diet has very few dairy products.

b) Infants of Vegetarian Mothers

When vegetarian women who are already Vitamin B12 deficient breastfeed their children, instead of giving them fortified formula milk, children develop this deficiency.

c) Underprivileged Children

Families that cannot afford to eat healthy diets consisting of B12-rich foods are likely to have children with this deficiency. It’s the leading cause of Vitamin B12 deficiency in third-world countries.

d) Children With Chronic Disorders

Children with chronic disorders that prevent them from consuming sufficient amounts of B12-rich foods can develop this deficiency. For instance, children with Bulimia – a psychiatric condition that prevents patients from eating large, healthy meals.

[Read : Binge Eating Disorder In Children]

3. Impaired Absorption of Vitamin B12

Let’s say a child’s mother is not B12-deficient. The child also consumes sufficient amounts of B12-rich foods every day. If the child still suffers from Vitamin B12 deficiency, impaired absorption is the likeliest causal factor. Impaired absorption refers to the malfunctioning of one or more organs involved in the step-by-step absorption of B12.

Consuming large amounts of B12-rich foods won’t solve this issue. Impaired absorption of this vitamin can cause states of severe B12 deficiency in children. Here are the types of children who suffer from this specific condition –

Children With Stomach Issues

The stomach produces the protein that enables Vitamin B12 absorption into the ileum. Here are the diseases that stop children’s stomachs from producing this vital protein –

a) Atrophic Gastritis/Pernicious Anaemia

In this disease, the child’s immune system erroneously attacks the gastric parietal cells in the stomach (the cells which make the vital factor for absorption of vitamin B12) or directly attacks the protein. This destruction causes anaemia, a disease that’s commonly associated with B12 deficiency. This is extremely rare in children

b) Pylori Gastritis

A relatively common stomach infection that damages the parietal cells and causes atrophic gastritis. This disease also hampers the stomach’s ability to produce the proteins vital for healthy absorption.

c) Stomach Loss

Children who have to undergo stomach surgeries (e.g., children with stomach cancers, oesophageal cancer, etc.) are likelier to develop this deficiency.

Other stomach or intestine related diseases that may cause faulty B12 absorption include – achlorhydria(low production of stomach acids), anaemia, Crohn’s disease and removal of large portions of the small bowel.

The amount of Vitamin B12 a child’s body needs changes with age. Here’s the recommended daily dose chart for children –

  • 1 to 3 years: 0.9 micrograms
  • 4 to 8: 1.2 micrograms
  • 9 to 13: 1.8 micrograms
  • Ages 14 and older 2.4 micrograms

These are very small amounts. The recommended Vitamin B12 dose is the same for both male and female children. In pregnant/lactating women, Vitamin B12 is required in higher amounts. The suggested day-to-day allowance for pregnant and lactating women is 2.6 and 2.8 micrograms, respectively.

Let’s explore how much of this vitamin should be present in their blood for their bodies to function normally. Bear in mind – lab reports will assess these levels to determine whether a child is B12 deficient or not.

  • New Born Babies: 160 to 1300 pg./ml
  • Children Over the Age of 14: 200 to 900 pg./ml

Children with less than 150 pg./ml are technically Vitamin B12 deficient Children with 200 pg./ml or more Vitamin B12 in their blood are healthy.

Food Sources For Vitamin B12

Children who are at risk of developing Vitamin B12 deficiency should prioritize consuming natural B12-rich food products. They’re the best sources of Vitamin B12 and far better than medications/supplements. In general, animal products (meat, seafood, and poultry in particular) contain the highest amounts of Vitamin B12. No plant, fruit or vegetable is a good source of Vitamin B12.

1. Seafood


  • Shellfish: A great source of Vitamin B12 and other elemental nutrients like Potassium, Iron, and Zinc.
  • Clams: By far the richest organic source of Vitamin B12. For every 100 grams of clams you consume, your blood gains 99μg of Vitamin B12.
  • Oysters: A medium-sized oyster will give a child’s blood a boost of 16 to 17μg of Vitamin B12.
  • Fish Eggs: Fish eggs like caviar (eggs of Sturgeon fishes) contain copious amounts of Vitamin B12. For every 100 grams of caviar you consume, your blood gains 20μg of Vitamin B12.

Other seafood items that are rich sources of Vitamin B12 include – octopus, herring, salmon, tuna, crabs, and lobsters.

2. Land Foods

beef liver

  • Beef Liver: For every 100 grams of beef liver you consume, your blood gains 83μg of Vitamin B12.
  • Turkey Liver: For every 100 grams of turkey liver you consume, your blood gains 43μg of Vitamin B12. Chicken liver contains 50% of Vitamin B12.
  • Lamb: The shanks and the legs of lambs provide relatively fewer amounts of Vitamin B12. Lamb’s shoulders are the richest sources of this vitamin (3.71μg per 100 grams consumed).

In terms of land-animal derived foods, livers are the richest sources of Vitamin B12. The livers of lambs, turkeys, geese, and ducks are the best sources of this vitamin.

3. Other Food Items

boy drinking milk

Cheese, Swiss cheese in particular (3.34μg per 100 grams consumed)

  • Chicken eggs (1.95μg per 100 grams consumed)
  • Milk and yoghurt are good sources of Vitamin B12 for vegetarians

Strict vegetarian children with this deficiency must get Vitamin B12 oral supplements or injections. However, natural sources of this vitamin are always better than synthetic, man-made alternatives.

Symptoms of Vitamin B12 Deficiency in Children

symptoms of Vitamin B12 deficiency

The symptoms of paediatric Vitamin B12 deficiency often mimic those of autism-related disorders. Unlike adults, infants with Vitamin B12 also have rapid onsets of symptoms that include –

  • Obsessive-compulsive behaviours
  • Difficulties with speech, comprehension, language, and writing
  • Aloofness
  • Fatigue, weakness
  • Redness in the linings of the mouth (the medical name of this condition is stomatitis)
  • Loss of appetite
  • Weight loss
  • Diarrhoea
  • Constipation
  • Megaloblastic anaemia (anaemia with large RBCs)
  • Pancytopenia (decrease in the production of white blood cells and platelets)
  • Irritability
  • Depression
  • Developmental delays
  • Numbness or tingling in the hands/feet (more common in older children)
  • Pale skin
  • Bleeding gums

Infants with Vitamin B12 deficiency can be misdiagnosed. They may be suspected of having autism if Vitamin B12 levels are not checked. Prolonged B12 deficiency can also lead to serious, life-changing conditions like spinal cord degeneration if unrecognised for a longer time.

If parents keep mistaking these symptoms as autism or gastric symptoms, long-term deficiency can even lead to comas. Children with Vitamin B12 deficiency are more vulnerable (to comas) than adults as their central nervous systems are underdeveloped.

Diagnosing Vitamin B12 Deficiency in Children

blood test to Diagnose cobalamin Deficiency

All children who are on vegan diets and anaemic must get Vitamin B12 deficiency screening. They face the highest risk of developing this deficiency. Doctors require laboratory evidence of Vitamin B12 deficiency before they start treatment. The diagnostic tests they recommend include –

  • Blood Tests: To verify CBC count.
  • Screening for Anaemia: Kids with Vitamin B12 deficiency often suffer from megaloblastic anaemia where their RBCs swell up.
  • Folic Acid Review: Folic acid is another “B” vitamin. Children with Vitamin B12 deficiency may have folic acid deficiency as well which also causes megaloblastic anaemia.

Treating Vitamin B12 Deficiency in Children?

child taking vitamin B12 injection

The treatment of children with Vitamin B12 deficiency depends on the cause/s of the deficiency. Mild and symptomatic Vitamin B12 deficiency can be treated with dietary adjustments. Removal of the underlying cause (e.g., curing a stomach problem) may also cure this deficiency.

However, in most cases, doctors struggle to completely eliminate the underlying causes in kids with Vitamin B12 deficiency. The next best solution is giving the children Vitamin B12 injections or oral doses. Daily Vitamin B12 injections or oral doses (1000μg) are given for one week or month, depending on the symptoms.

Doctors may give maintenance doses after reviewing the child’s recovery. Children with serious symptoms must be given instant treatment with Vitamin B12 injections. Delay in treatment may increase the risk of long-term damage. Additional forms of treatment and post-treatment depend on the age at which the deficiency began.

In most cases, children with Vitamin B12 deficiency improve dramatically with appropriate dietary changes and injections. However, some children (especially the ones with serious symptoms) may suffer from long-term neurological damage.

[Read : 10 Tips To Make Milk Tastier For Children]

Prevention of Vitamin B12 Deficiency in Children

folic acid

Parents can take steps at home to improve their children’s Vitamin B12 intake by creating diets that contain –

  • Meat, milk, fish, cheese, and eggs – all rich sources of Vitamin B12
  • Leafy green vegetables and citrus fruits do not have vitamin B13 but give children folic acid which is another vitamin necessary for red cell production.
  • Daily Vitamin B12 pills (for vegetarians)

Babies born with faulty absorption issues can prevent deficiency by taking Vitamin B12 shots.

Long-Term Side Effects of Vitamin B12 Deficiency in Children

If left untreated, Vitamin B12 deficiency in children can spiral into severe neurological complications (e.g., partial paralysis). This deficiency can also cause osteoporosis, depression, anaemia, and severe cognitive declines if not managed properly. Children receiving treatment for vitamin B12 deficiency need constant monitoring for up to 6-12 months.

Regular monitoring of vitamin B12 levels throughout the child’s long-term treatment helps doctors avoid serious long-term complications.


1. Can the Damage Done to a Child’s Brain Due to Vitamin B12 Deficiency be Reversed?

Yes, it can be reversed if diagnosed early and treated well. Some studies have proved that negative effects of Vitamin B12 deficiency, such as brain atrophy, can be reversed with treatment.

2. How to Avoid the Risk of My Child Getting Vitamin B12 Deficiency?

Give your child Vitamin B12 deficiency screening tests especially if your family is on a vegetarian diet. Never treat symptoms like aloofness or irritability as character traits. Screening for Vitamin B12 deficiency is safe and cost-effective.

3. Can My Vitamin B12-Deficient Child Continue to be a Vegetarian?

Yes. Vegetarian children can receive synthetic doses of Vitamin B12. However, the most efficient way of treating Vitamin B12 deficiency in children is by incorporating organic B12-rich food items such as milk, yogurts, and cheese, etc into the regular diet.

Read Also: Teenagers With Epilepsy: Causes and Challenges

Dr. Stalin Ramprakash, MBBS, MD, MRCPCH, CCT, FRCPCH
Consultant - Paediatric Haematology, Oncology and BMT, Aster CMI Hospital
21 years of experience

Dr. Stalin Ramprakash is an experienced and dynamic consultant who provides high-quality comprehensive care for children with cancer and blood-related problems. He completed his paediatric training in Madras Medical College and pursued further training in the United KingdomRead more.

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