Vitamin D was once regarded as a nutrient important for bone health, but it's now known that this steroid hormone influences virtually every cell in your body, including those in your brain. Far from just influencing your physical health, vitamin D plays a role in mental health and may influence behavior — even years down the road.
As such, ensuring children's vitamin D levels are optimized is also important, as a deficiency in childhood may affect their behavior in adolescence, according to a University of Michigan study.1
Low vitamin D in childhood linked to behavior problems later
The study involved 273 school-aged children between the ages of 5 and 12 years, living in Bogota, Colombia, who were part of a larger cohort study that began in 2006 and involved follow-up interviews conducted after six years. Part of the interviews assessed the children's behavior, and the researchers also checked the children's vitamin D levels via blood samples that were collected at the start of the study.
Vitamin D deficiency, defined as a vitamin D level of less than 20 ng/mL (or 50 nmol/L) was found in 10.3% of the children.2 Further, those with a deficiency at the start of the study were 1.8 times as likely to display behavior problems in later childhood, when they were 11 to 18 years old.3
"Children who have vitamin D deficiency during their elementary school years appear to have higher scores on tests that measure behavior problems when they reach adolescence," Eduardo Villamor, professor of epidemiology at the University of Michigan School of Public Health, said in a news release.4 This includes more "externalizing" problems, such as aggressive and rule-breaking behaviors.
Vitamin D's connection to emotional and behavioral problems
Separate research was published in 2017 that also linked vitamin D to emotional and behavioral problems in adolescents.6 In an analysis of 9,068 participants, lower vitamin D status was associated with increased emotional problems, peer relationship issues and behavioral difficulties among children. Further, a slight increase in vitamin D (10 ng/ml for boys and 10.2 ng/ml for girls) was linked to a decrease in total behavioral difficulties.7
"Based on the large-scale cross-sectional study in a German population-based sample of children and adolescents we detected inverse associations between 25(OH)D [vitamin D] concentrations and both parent- and self-rated SDQ scores of the total difficulties scale and different subscales with the strongest association in the subsample aged ≥12-<18 years for both genders," the researchers explained.8
Vitamin D receptors exist in the human brain,9 hinting at the importance of this vitamin in mental and emotional health. It's believed that vitamin D regulates more than 200 different genes by binding to vitamin D receptors that are responsible for driving a number of biological processes.10 Low levels of vitamin D have, in fact, been linked to a number of psychological disorders, including anxiety, depression and schizophrenia.
It likely influences psychological health in a number of ways, including by modulating inflammation, regulating proteins that fight free radicals and increasing the synthesis of brain-derived neurotrophic factor, which may play a role in schizophrenia.
Taken together, vitamin D exerts a neuroprotective role in the brain.11 Writing in the journal Children, Dr. Joy Weydert of the department of pediatrics at the University of Kansas Medical Center explained:12
"Activated vitamin D also has neuroprotective effects via neuromodulation, anti-inflammatory, anti-ischemic, and anti-oxidant properties. Having adequate vitamin D levels in-utero and early stages of life ensures normal receptor transcriptional activity vital for brain development and mental functioning.
Vitamin D affects the proteins directly involved in learning, memory, motor control, and social behavior, and is closely associated with executive functioning such as goal-directed behavior, attention, and adaptability to change."