Eating and drinking foods high in sugar early in life can pave the way for learning and memory problems later in adulthood, according to a new study from the University of Southern California. The findings are of particular concern in light of how many food products marketed to young people contain high levels of corn syrup and other sugars.
Several studies have found that various foods have different effects on the “good” bacteria found in the intestine; diets high in fat and sugar and low in fiber, for example, are associated with several health problems. This latest study focused on sugar and its potential impact on cognitive function in adulthood.
The research involved young rats who had unlimited access to a sugary drink similar to the soft drinks and other sweetened drinks that teenagers usually drink. Two methods were used to test the rats’ memories when they reached adulthood, including one that tested memory controlled by the perirrinal cortex and one that tested memory controlled by the hippocampus.
When compared to rats that received plain water without a sweetener, rats that received unlimited access to sugary drinks had problems with the function of memory controlled by the hippocampus, but not with the function related to the perirrinal cortex.
The scientists also found differences in intestinal bacteria between the two groups of mice, with the sugary drink group showing a greater number of two specific species of intestinal bacteria called Parabacteroides distasonis and Parabacteroides johnsonii.
Mice that received water and that received Parabacteroides transplants had memory problems similar to those of mice that drank the sugary drink – and they also developed memory problems controlled by the perirrinal cortex.
The findings directly link the changes in intestinal bacteria induced by the diet to cognitive function, highlighting the importance of limiting sugar consumption, especially in young people who are usually attracted to sweet drinks and treats.