G.B.
It could be an iron deficiency, A disease known as PICA is caused by lack of iron , where people eat ineidble items.
My son sucked his shirt, but also chewed on leggos, beads, money, anything he can fit in his mouth. I recently started supplementing him.
He no longer chews his clothes.
Look for any of these signs of zinc deficiency :
white marks across fingernails
can't concentrate/ADD
may have apathy, depression
headaches or dizzy
more infections than average
skitsophrenia
boils
slow healing or growth
cracks begind ears
hair loss
restless leg syndrome
Vitamin c increases absorption.
Any of these can cause iron deficiency:
parasites
antacids
being vegan
being a child
being elderly
pregnant
rapid growth
caffeine/coffee/tea
asprin
antibiotics
coumadin (blood thinner)
and calcium may decrease iron