The mineral is essential for forming and developing synapses in the brain when the baby is in the womb, and so giving zinc supplements to the mother when she is pregnant could be one antidote to the epidemic, say researchers at the Stanford University School of Medicine.
Infants with autism could also take the supplements and this may possibly reverse the condition.
Zinc works by binding two proteins—Shank2 and Shank3—that are essential for the formation and development of synapses which, in turn, allow neurons to communicate.
"A lack of zinc during early development might contribute to autism through impaired synaptic maturation and neuronal circuit formation," said Prof John Huguenard, one of the researchers.
The researchers say the jury's still out as to whether zinc deficiency is directly linked to autism, mainly because there haven't been any controlled studies on treating autism with zinc supplements, either when the woman is pregnant or when the infant has been diagnosed with the condition.
They point out that too much zinc reduces the amount of copper the body can absorb, which can lead to anaemia and bone weakening. It's also possible that the deficiency could also be the result of a poorly-functioning gut that doesn't absorb zinc properly.