In the largest study of its kind and recently published in The Journal of Epidemiology and Community Health, toddlers who ate a diet higher in junk food were more prone to develop lower IQ levels later in life.
Nearly 14,000 children from Western England born between 1991 and 1992 participated in the program conducted by the School of Social and Community Medicine at the University of Bristol. Researchers looked at data provided by parents, which detailed dietary habits ranging from highly "processed" foods, "traditional" meat-oriented diets and one considered to be more "health conscious" with a focus on fruits, vegetables, pastas and rice.
Of the 14,000 in the program roughly 4,000 children provided complete data on their diets. When the children were 8.5 years old, they were given the Wechsler Intelligence Scale test that revealed there was a significant difference in IQ among those who had had the "processed" as opposed to the "health conscious" diets in early childhood. The study states, "the 20 percent of children who ate the most processed food had an average IQ of 101 points, compared with 106 for the 20 percent of children who ate the most "health-conscious" food."
Vital nutrients may often be lacking in processed foods—even in those proclaiming to be "fortified" with vitamins and minerals—as scientists have long speculated that a certain unknown synthesis of nutrients occurs in whole foods versus isolation of key components.
Additional risks of processed foods include behavioral problems from artificial colors, flavors and other ingredients that have been linked to developmental issues, which could also be a factor in the decreased IQ levels.
IQ tests (intelligence quotient) have been used since the early 20th century to account for a number of factors in a child's intelligence and cognitive development. Despite the effects of processed foods on IQ levels as proposed in the study, average IQ scores for many populations have been rising at an average rate of three points per decade since the early 20th century in a phenomenon called the Flynn effect.
Keep in touch with Jill on Twitter: www.twitter.com/jillettinger