A new study, published in the Molecular Psychiatry, specified that dietary glycemic index is often linked to symptoms that are characteristic of autism spectrum disorder (ASD).
The autism rate has increased dramatically and is defined by social avoidance, repetitive behaviors and difficulty communicating and has risen dramatically over the past two decades for reasons that are unclear. Researchers are trying to clarify the exact cause for the disease.
The scientists determined that following a high glycemic index diet leads to a higher number of activated immune cells in the brain and more genes associated with inflammation.
The glycemic index is based on a food ranking provided to foods containing a specific amount of carbohydrates and their blood sugar level impact. The new study found that the diet might directly influence the ecosystem of bacteria in the gut. More complex starches are broken down by bacteria that live in the lower part of the gut, the large intestine. The group saw some evidence of that in the blood, detecting metabolites that could only have come from the gut in larger amounts in the animals fed the high-glycemic index diet.
‘We were really surprised when we found molecules in the blood that others had reported could only be generated by gut bacteria,’ Maher says. ‘There were big differences in some of these compounds between the two diets.’
Foods commonly found in the Western lead to a major fluctuation of blood sugar levels due to their rapid ability to be digested. These foods include bread, cereals and sugary processed foods lead to rapid increases and decreases in blood sugar levels.
“One thing that’s driving a lot of general physiological changes in people is changes in the diet,” said corresponding author Pamela Maher, a senior staff scientist at the Salk Institute for Biological Studies in La Jolla, CA.
“We were really surprised when we found molecules in the blood that others had reported could only be generated by gut bacteria,” said Maher. “There were big differences in some of these compounds between the two diets.”
Dietary glycemic index modulates the behavioral and biochemical abnormalities associated with autism spectrum disorder, Antonio Currais et al., Molecular Psychiatry, doi: 10.1038/mp.2015.64, published online 9 June 2015, abstract.