Scientists fed mice sugary soda for two months, and the brains of the younger mice were impaired

Should we even be surprised?
Ameya Paleja
Mouse and sugary soda
Mouse and sugary soda

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Scientists at a Brazilian research institute fed sugary soda to rats for two months and found that their brains suffered significant damage, Futurism reported.

High sugar content in soda and other foods is a well-known health hazard, with years of research suggesting its role in diseases such as diabetes, heart disease, dental issues, and many more ills. Health experts have been campaigning for warning labels on food products with damaging sugar levels.

While the debate is still ongoing about whether this needs to be done, there is new evidence to suggest that long-term consumption of sugary sodas can impair cognition, cause cellular distress and result in memory issues.

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.

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While studying the hippocampus, the researchers found that CAT activity was increased in the 2-and 8-month-old rats, while DCFH levels were elevated in rats of all ages. The hippocampus too plays a role in memory and learning, and humans have been associated with disorders such as anxiety, depression, and bipolar disorder, to name a few.

Overall, the researchers found that oxidative stress increased on long-term consumption of sugary soda, as did memory impairment, and the younger rats seemed to be more prone to behavior alterations on their consumption.

However, since rats are not humans, these findings cannot be directly extrapolated to have the same effects on us. Nevertheless, they serve as a warning of the likely impact of long-term consumption of these sugary drinks could be.

The findings were published in the journal Experimental Gerontology.



The consumption of soft drinks has increased considerably in recent decades, mainly cola soft drinks. Excessive consumption of cola-based soft drinks is associated with several diseases and cognitive decline, particularly memory impairment. Furthermore, diets with high sugar can promote insulin resistance, metabolic syndrome, and dyslipidemia.


Thus, the present study aimed to evaluate the effect of cola soft drink intake on behavioral alterations and oxidative damage in 2-, 8- and 14- month-old male Wistar rats.

Results and discussion

The cola-based soft drink intake caused memory impairment in the radial-arm maze, Y-maze task, and open-field in the 2- and 8-month-old rat, but not in the 14-month-old. There were no difference among groups in the inhibitory avoidance test. In the frontal cortex, soft drink intake reduced CAT activity in the 8-month-old rats and SOD activity in the 8- and 14-month-old rats. In the hippocampus, the soft drink increased CAT activity in 2- and 8-month-old rats, increased DCFH levels at all ages, and increased TBARS levels in 2-month-rats. Therefore, the results show that long-term soft drink intake leads to memory impairment and oxidative stress. The younger seems to be more susceptible to the soft drink alterations on behavior; however, soft drink caused alterations in the oxidative system at all ages evaluated.