Zinc and Its Role In Supporting Neurocognition and Behaviour
Zinc plays an instrumental part in many aspects of human health, including protein and DNA synthesis, wound healing, bone structure, and the immune system. (1) It also plays a major role in synaptic transmission. (2) As the body does not store zinc, it must be supplied by the diet and/or supplements. (2) Most people in developed countries meet their recommended zinc levels through dietary intake, primarily red meat, poultry, beans, fortified breakfast cereals, and dairy products. (3) Zinc deficiency is more common in the developing world due to poor diet, but certain conditions such as kidney disease, sickle-cell anemia, or other chronic diseases may lead to malabsorption, and therefore, deficiency, even with adequate dietary intake. (3) Symptoms of zinc deficiency include inattention, hair loss, jitters, delayed cognitive development, dermatitis, diarrhea, poor growth, suppression of aspects of cell-mediated immunity, and retarded development. (1, 3)
Zinc deficiency has been observed in numerous neuropsychiatric disorders, and a protective role of zinc has been hypothesized in some of these disorders. (2) Children diagnosed with ADHD have also commonly been shown to be deficient in zinc. (1, 3) Children with ADHD often have a very limited repertoire of foods, and may also experience appetite suppression if they are taking stimulants. (1, 2) This lack of dietary variety and appetite is one possible explanation for the increased zinc deficiency amongst the ADHD population. (1) Another hypothesis for low zinc levels, common also in major depressive disorder in adults, is increased inflammation in the body. (1)
Zinc has a function in the pathway for the body’s production of neurotransmitters and prostaglandins, which are hormone-like substances with numerous functions in the body, including inflammation modulation. (1) Zinc also supports the production and regulation of melatonin, a crucial element in the pathophysiology of ADHD due to its modulation of dopamine. (1, 2) The dopamine transporter, which is the where psychostimulants act to treat ADHD, is bound and regulated by zinc. (1)
Numerous studies have demonstrated positive results for supplementing with zinc for the treatment or alleviation of ADHD symptoms. (1) One randomized controlled trial including 400 boys with ADHD showed significant improvements in hyperactivity, impulsivity, and socialization in those supplemented with zinc. (1) In another study, students supplemented with zinc, as opposed to a placebo, were reported to have reduced oppositional behaviours, such as anger, disobedience or aggression, by their classroom teacher. (2) Evidence supports the recommendation that zinc may be a safe and cost-effective intervention for ADHD patients, or those with related symptoms and low zinc levels. (1)
1. Villagomez A, Ramtekkar U. Iron, Magnesium, Vitamin D, and Zinc Deficiencies in Children Presenting with Symptoms of Attention-Deficit/Hyperactivity Disorder. Children (Basel, Switzerland). 2014;1(3):261-79.
2. Ghanizadeh A, Berk M. Zinc for treating of children and adolescents with attention-deficit hyperactivity disorder : a systematic review of randomized controlled clinical trials: Nature Publishing Group; 2012.
3. Bloch MH, Mulqueen J. Nutritional supplements for the treatment of ADHD. Child Adolesc Psychiatr Clin N Am. 2014;23(4):883-97.
Written By Brittany Darling
NUTRITIONIST (BHSC), WESTERN HERBAL MEDICINE (ADV DIP),
CERT. PAEDIATRIC NUTRITION