How did the researchers test for the effect of sugary sodas?
To test the impact of long-term consumption of sugary sodas, the researchers experimented with three groups of rats, each categorized by age, viz., 2-month, 8-month, and 14-months. Each of these groups was further divided into two, where one subgroup received only water as a drink while the other received sugary sodas and water.
The experiment ran for 67 days, and on the 68th day, the rats were euthanized to allow the researchers to study the rat brains from the inside. Before killing them, the researchers also ran the rats through some maze tests between days 57 and 67 of the experiment.
What did the researchers find?
In the behavioral tests, the researchers found that the soda-drinking younger rats, the two and eight months old, showed memory impairment in multiple maze-based tests, although the older ones did not.
The rats were killed to gain access to their brains, where the researchers looked for markers of oxidative stress such as thiobarbituric acid reactive substances (TBARS) and dichloro-dihydro-fluorescein diacetate (DCFH). Additionally, levels of catalase (CAT) and superoxide dismutase (SOD), which are antioxidant enzymes, were also measured.
While studying the frontal cortex, the researchers found that the sugary soda intake reduced CAT activity in the 8-month-old rats while reducing SOD activity in the 8-month and 14-month-old rat brains. The frontal cortex is the area of the brain that plays a role in functions like memory, attention, and judgment.