Autism Spectrum Disorder is a neurodevelopmental disorder characterised by intellectual and social impairments including communication and language use as well as unusual and restricted patterns of behaviours, interests and activities and sensory sensitivities such as avoiding loud sounds.

Zinc deficiency has been shown to impact a number of protein molecules in the brain resulting in hypotonia, seizures and even “autistic-like” behaviours. Statistics show that up to 50% of autistic patients between the ages of 0 and 3 have a zinc deficiency compared to less than 1% in healthy patients (Yasuda et al., 2011).

Grabrucker et al. (2014) carried out a study looking at the role zinc plays on the family of proteins in the brain and how that leads to the presence of autistic related behaviours. They tested mothers and infants (prenatal) with zinc deficiency (acute) in mice as well as patients with Phelan-McDermid syndrome which is characterised by global developmental delay, severely impaired speech and autistic-like behaviours.

For the mice, they did a number of behavioural tests looking at social behaviour and for patients with Phelan-McDermid syndrome, they took a blood test and measured levels of copper and zinc in their blood.

They found that acute zinc deficient mice showed an increase in reactivity in maternal care situations compared to normal mothers. Mothers who were zinc deficient when they were infants show less maternal behaviour when responding to calls from their litter. Prenatal zinc deficient mice showed an auditory discrimination impairment as they were unable to distinguish between an important or neutral sound stimulus.

In terms of the ultrasonic vocalisations that infants give off as a call to their mothers, zinc deficient infants vocalised less calls per minute compared to controls and their calls were reduced in loudness. Some of these behavioural features that the zinc deficient prenatal mice are displaying are consistent with autistic related behaviours.

Grabrucker et al. (2014) found an increase in the likelihood of having a zinc deficiency in patients with Phelan-McDermid syndrome especially below the 12 years old. This study therefore suggests that zinc may contribute to autism spectrum disorders and giving zinc therapy to children with autism may improve their attention, hyperactivity etc.

Alanna Wong