By Megan Tseng
Snickers, Reese’s, Starburst, Skittles. For some of us, these could be the occasional Halloween indulgence. For others, these are part of the daily diet.
According to the American Heart Association, a child should have no more than 25 grams of sugar per day, equivalent to about 6 regular-sized marshmallows. The average American child consumes 418 grams of sugar daily, which amounts to 100 marshmallows. Concerning, to say the least.
Regardless, we should all be paying better attention to our daily sugar consumption. Not only are they recipes for obesity and cavities, new research shows that these sweet treats might actually be bad for the brain.
The amount of sugar contained in a Snickers bar, one of America’s most popular candies. Each sugar cube equates to 4 grams of sugar.
To investigate sugar’s effect on a child’s brain, researchers at the University of Georgia conducted a study in which they tested the memories of mice after a high sugar intake.
They first fed some of the mice an 11% sugar solution, in proportion to a typical sweetened beverage. The scientists then measured their episodic contextual memory, testing how well they were able to recall the location in which they saw an object. They then tested their basic recognition memory, in which the mice had to recognize an object they had previously encountered. Curiously, mice who drank the sugar solution showed impaired ability in the episodic contextual memory task, but normal function in the basic recognition memory task.
Both of these types of memory are dependent on the hippocampus, an region of the brain located in the temporal lobe. The hippocampus is commonly associated with memory and learning, and is able to process and retrieve declarative and spatial memories. Episodic contextual and basic recognition are two types of declarative memories, and are hippocampal-dependent; damage to the hippocampus can prevent these memories from being properly stored and retrieved. The mice’s impaired abilities to perform episodic contextual memory tasks point directly to damage in the hippocampus.
The hippocampus is one of the most essential brain areas associated with memory and learning.
The Brain and Parabacteroides
Further investigation of this phenomenon showed elevated levels of Parabacteroides in the mice’s guts. While intestinal bacteria are usually helpful for human digestion and even mental well-being, excessive amounts can be damaging to our body systems.
In an additional segment of the study, researchers experimentally increased the mice’s levels of Parabacteroides rather than their sugar intake. After putting the mice through some more memory tasks, they found that the mice showed impairment in both hippocampal-dependent and hippocampal-independent memories. This indicates negative effects in the hippocampus as well as surrounding brain regions, and could be a clue to how sugar impairs brain function through its influence on Parabacteroid levels.
The research has shown that high sugar intake can impair brain activity, especially targeting the hippocampus. The next step is to identify how these Parabacteroides influence cognitive function. By understanding more about their effects on the brain, scientists can find out more about the ideal conditions for brain growth and development during early life.
“Added Sugar in the Diet.” Harvard T.H. Chan School of Public Health, Harvard College, 2021, www.hsph.harvard.edu/nutritionsource/carbohydrates/added-sugar-in-the-diet/#ref27.
Jenco, Melissa. “AHA: Limit children’s sugar consumption to 6 teaspoons per day.” AAP News, American Academy of Pediatrics, 23 Aug. 2016, www.aappublications.org/news/2016/08/23/Sugar082316.
Noble, Emily E. et al. “Gut microbial taxa elevated by dietary sugar disrupt memory function.” Translational Psychiatry, 31 Mar. 2021, www.nature.com/articles/s41398-021-01309-7.
Powell, Cal. “Sugar not so nice for your child’s brain development.” UGA Today, University of Georgia, 31 Mar. 2021, news.uga.edu/sugar-not-so-nice-childs-brain-development/.