The Signs And Symptoms Of A Vitamin B12 Deficiency

Anxiety, depression, aggressiveness and breaking rules can be signs of these mineral and vitamin deficiencies in boys.

Anxiety, depression, aggressiveness and breaking rules can be signs of these mineral and vitamin deficiencies in boys.

Mental signs of a vitamin B12 deficiency include depression, memory issues, confusion and irritability.

Now, a study finds that children with behavioural problems might be deficient in important nutrients such as iron and B12.

A study has found that boys with low blood levels of vitamin B12 and iron could exhibit some problematic behaviours such as depression, anxiety, breaking rules, and being aggressive.

Professor Eduardo Villamor, the study’s co-author, said:

“Iron deficiency is still highly prevalent in many regions worldwide.

There is less data on vitamin B12 deficiency but available evidence also suggests it may be a substantial public health problem in certain populations.”

For this study, 3,202 children aged 5 to 12 years old from primary public schools were randomly selected and followed-up for 6 years.

The research team wanted to see if micronutrient deficiency in children would lead to mental health problems.

Several health issues were linked to poor diets lacking micronutrients such as iron and vitamin B12.

They found that internalizing and externalizing behaviours in male adolescents were strongly related to anaemia (iron deficiency), and low levels of vitamin B12 through their childhood.

Professor Villamor said:

“Interventions to curb these deficiencies must be informed by knowledge of their causes in each specific setting.

In our study population, for example, we showed before that a school snack program increased vitamin B12 blood levels after three months.”

Past studies have found that iron deficiency in infants would reduce the alertness, self-soothing, and self-regulation such as ability to focus, control body function, and manage emotions.

These issues possibly develop further during childhood and could lead to behavioural problems in teenagers and poor mental health in their adulthood.

The study didn’t find any link between vitamin B12 and iron deficiency among girls and behaviour problems.

This may be related to differences in physical and psychological changes at puberty between girls and boys.

Professor Villamor said:

“We don’t have a clear explanation of why there were sex differences, although we knew it was important to study boys and girls separately because they may differ in the timing of development.

Studies in rats have found that some micronutrient deficiencies affect male and female brains differently but it is not clear exactly why this may also be the case in humans.”

Physical rather than mental symptoms of a vitamin B12 deficiency include headaches, fatigue, breathlessness and pale skin.

Taking a B12 supplement is one of the easiest ways to combat this problem.

Adults need around 1.5 mcg per day.

About the author

Mina Dean is a Nutritionist and Food Scientist. She holds a BSc in Human Nutrition and an MSc in Food Science.


The study was published in The Journal of Nutrition (Robinson et al., 2018).


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This site is all about scientific research into how the mind works.

It’s mostly written by psychologist and author, Dr Jeremy Dean.

I try to dig up fascinating studies that tell us something about what it means to be human.

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