Vitamin B12 is essential for blood formation and for the development of the nervous system. The body cannot make it; it comes only from animal foods (meat, fish, eggs, milk and dairy). B12 deficiency is therefore a preventable problem directly linked to eating habits.

Its importance in children is this: if deficiency lasts, not only anaemia but also a pause in developmental milestones and neurological signs may appear. Treatment is straightforward when it is caught early.

Who is at risk?

  • Exclusively breastfed babies, if the mother's B12 level is low
  • Children who eat no animal foods (vegan) or very few
  • Babies who are given too little meat, egg and dairy during weaning
  • Conditions that impair absorption: coeliac disease, chronic bowel disease, previous gastrointestinal surgery
  • Long-term use of acid-suppressing medicines
  • Babies born prematurely

In Turkey, the most common cause of B12 deficiency in babies is an unrecognised deficiency in the mother.

Why is it noticed late?

The signs settle in slowly and are confused with other causes:

  • Poor appetite, listlessness, pallor
  • A pause in developmental milestones or loss of acquired skills (sitting, holding on, babbling)
  • Reduced muscle strength, floppiness
  • Irritability, disturbed sleep
  • In older children: fatigue, poor concentration, falling school performance
  • A sore red tongue, cracks at the corners of the mouth
  • Tingling and numbness in the hands and feet

None of these alone makes the diagnosis, but in a child at risk with a developmental pause, B12 must always come to mind.

How is it diagnosed?

The blood B12 level is measured. With borderline values the doctor may request additional tests. A full blood count is assessed in the same sample: in B12 deficiency red cells may be larger than normal. If iron deficiency coexists, this enlargement can be masked, so the assessment is made as a whole. Our article on iron deficiency anaemia helps to tell the two apart.

Treatment

Treatment is planned according to the depth and the cause of the deficiency:

  • Severe deficiency is usually loaded with intramuscular injections, followed by oral supplementation
  • Mild to moderate deficiency may be covered by oral drops or tablets
  • If absorption is impaired, oral treatment is insufficient and the underlying cause is investigated
  • When deficiency is found in a baby, the mother is assessed and treated if needed

The response is usually quick: appetite and alertness start to improve within days. Neurological signs take longer to resolve, which again shows the value of early diagnosis.

Prevention through diet

  • During weaning, meat, egg yolk, yoghurt and cheese should be on the table regularly
  • After the first year, milk and dairy should be part of the daily diet
  • Supplementation is essential for children on a vegan diet and for vegan mothers who breastfeed
  • Assessing B12 in pregnancy prevents deficiency in the baby from the outset

For a month-by-month plan for weaning see our guide to starting solids.

When to see a doctor

  • If the baby is losing acquired skills or development has stalled
  • If pallor, listlessness and poor appetite occur together
  • If the child follows a vegan diet without regular supplementation
  • If the mother has been found to be B12 deficient

For a nutritional assessment and well-child follow-up you can book an appointment at Özel Düztepe Yaşam Hospital in Şahinbey.