Dietary vitamin B12 is found primarily in animal products including dairy, eggs, meat, and fish. Vegans and some vegetarians have limited B12 intake from food sources such as mushrooms and nori. Vitamin B12 is derived largely from dietary animal products such as dairy products, eggs, meat, and fish. Vegans have limited dietary B12 options because vegetables such as mushrooms and nori have very little B12. Prenatal vitamins contain vitamin B12, but a significant percentage of pregnant and lactating individuals don’t take vitamins.

Low vitamin B12 intake during pregnancy leads to low fetal stores of B12 and low levels in breastmilk.

Vitamin B12 is vital for infant growth and development, and particularly for brain health.

This week’s study reviews data from published cases and describes biochemical and clinical information on infants diagnosed with vitamin B12 deficiency, to raise awareness of this condition for early diagnosis.

The authors’ literature review yielded 102 publications from countries in 6 different continents, reporting on 292 published cases of infant B12 deficiency from 1962-2022.

They found that clinical signs of vitamin B12 deficiency in infants typically occur in the first few months of life, often manifesting symptoms of developmental regression, irritability, feeding difficulties, low tone, and movement disorders. Although infant symptoms may start early, the diagnosis of vitamin B12 deficiency is often made significantly later.