Children who do not get enough zinc while in the womb may be more likely to develop autism, says a new study.
Scientists do not yet have a definitive answer for what causes autism, but the vast majority of research shows that it is a combination of "environmental factors" and genetic defects.
In a new paper published today, US and German scientists say they have evidence that zinc levels can be one of the environmental factors that define the seeds of behavioral disorder.
Further research is needed to confirm whether there could be a causal link, but the team claims to have established a possible mechanistic link.
US and German scientists say they have evidence that zinc levels can be one of the environmental factors that define the seeds of autism spectrum disorder
They found that zinc shapes the connections or "synapses" between brain cells that are formed during initial development, through a complex molecular mechanism encoded by the autism risk genes.
However, precautionary research is in its early stages and the findings do not mean that pregnant women should start taking zinc supplements to prevent autism.
Senior author Sally Kim of Stanford University School of Medicine in California said: "Autism is associated with specific gene variants involved in the formation, maturation and stabilization of synapses during initial development.
"Our results link zinc levels in neurons – through interactions with proteins encoded by these genes – to the development of autism".
Co-senior author Professor Craig Garner of the German Center for Neurodegenerative Diseases added: "Currently there are no controlled studies on the risk of autism with the integration of zinc in pregnant women or children, so the jury is still out .
"At this point we can not really draw conclusions or recommendations for zinc supplementation, but experimental work in autism models also published in this Frontier research topic is promising.
"Nonetheless, our results offer a new mechanism to understand how zinc deficiency – or the perturbed management of zinc in neurons – can contribute to autism."
Zinc helps to produce new cells and enzymes, to process carbohydrates, fats and proteins in food and to heal wounds.
Foods rich in minerals include meat, shellfish, dairy products such as cheese, bread and cereals.
The national health service said that most people get enough zinc from their diet and should not take more than 25 mg of zinc supplements a day unless it was recommended by a doctor.
Too much reduces the amount of copper the body can absorb, which can lead to anemia and weakening of the bones.
The study published in the journal Frontiers in Molecular Neuroscience found when a signal is transferred through a synapse, the zinc enters the target neuron where it can bind two of these proteins – Shank2 and Shank3.
These proteins in turn cause changes in the composition and function (& # 39;) of adjacent signal receptors, called 'AMPARs', on the surface of the neuron at the synapse.
The experiments showed the mechanism of maturity of AMPAR mediated by zinc-Shank in the development of synapses.
The main author of dr. Huong Ha, a researcher at Stanford, explained: "In the development of rat neurons, we have found that Shank 2 and 3 accumulate at synapses in parallel with a transition to mature AMPARs.
"The addition of extra zinc accelerated the switch, but not when we reduced the accumulation of Shank 2 or 3.
"Furthermore, our study mechanically shows how Shank2 and 3 work in agreement with zinc to regulate the maturation of AMPAR, a fundamental step for development."
In other words, Professor John Huguenard of the co-senior author, also of Stanford, added that zinc models the properties of synapse development through Shank proteins.
Prof. Huguenard concluded: "This suggests that lack of zinc during early development could contribute to autism through a compromise of synaptic maturation and the formation of neuronal circuits.
"Understanding the interaction between zinc and shin proteins could therefore lead to diagnostic, therapeutic and prevention strategies for autism."
- Note to readers: talk to your doctor before changing your diet