Around one-quarter of people may have a vitamin B12 deficiency.
Memory and thinking problems can be a sign of vitamin B12 deficiency, research finds.
Similarly, people experiencing a mood disorder, like depression, can also be deficient in vitamin B12.
The body uses vitamin B12 to make red blood cells and to keep the nervous system healthy.
Around one-quarter of people may have a vitamin B12 deficiency
Other, more common signs of vitamin B12 deficiency include feeling tired, experiencing muscle weakness and being constipated.
Memory and thinking problems can strike from an early age.
One study of Colombian children found that children deficient in vitamin B12 were at more than twice the risk of repeating a grade.
Deficient children were also almost twice as likely to be absent from school as those who were not.
The study included 3,156 students aged 5-12 who were attending primary schools in Bogotá, Colombia.
They were tested for a range of nutritional markers, including B12, folate, zinc and vitamin A.
The results showed that 15 percent were marginally deficient in vitamin B12.
Only a deficiency in vitamin B12 was linked to a child having to repeat a grade.
Dr Eduardo Villamor, who led the study, said:
“Vitamin B12 is necessary for adequate brain development.
Deficiency very early in life or in old age has been linked to cognitive and behavioral problems, but it was not known whether it could be related to academic difficulties during school age.
Grade repetition and school absenteeism are important outcomes because they predict school dropout and impair children’s options for educational advancement and development.”
Vitamin B12 deficiency is easy to rectify with supplements or by dietary changes.
Vitamin B12 levels can be boosted through supplementation or by eating foods such as dairy, liver, salmon and eggs.
The study was published in The Journal of Nutrition (Duong et al., 2015).