Persistent childhood diarrhea detrimentally affects IQ for 10 years and possibly longer.
Richard Guerrant of the University of Virginia in Charlottesville and colleagues came to this conclusion after following hundreds of Brazilian shantytown children for 14 years.
They found that the number of days children suffer from diarrhea in the first years of life is directly related to diminished cognitive function later, suggesting that diarrhea causes permanent brain damage.
“Repeated short illness with diarrheal episodes in the first two years of life may be enough to cause this affect,” Guerrant says in an interview with Chemistry & Industry Magazine.
And while the brain may recover somewhat, “the persistence of significant effects four to 10 years later suggests that the effects on IQ may be lastingly important,” says Guerrant.
While diarrhea is known to affect physical growth and fitness, the link between diarrhea and intelligence has not been well established.
This study changes that, as the researchers found that the best single predictor of how children are doing in third grade is how much diarrhea they had in the first two years of life.
Guerrant thinks that this is because children with persistent diarrhea don’t absorb nutrients vital to brain development.
If this proves to be true, supplementation could help address the problem.
Such a solution could have a dramatic impact, as diarrhea in infancy is thought to reduce economic productivity in adulthood by 10%.