Often feel that your memory is worse than others?
Is it possible that I ate too much sugar when I was a child?
Scientists from the University of Georgia and the University of Southern California have found for the first time:
Consuming too much sugar during the rapidly developing childhood phase of the brain can impair memory function in adulthood.
△ The results were published in the nature sub-journal
What's going on?
Are harms like tooth decay and obesity not enough?
How did you come to this conclusion?
The scientists first divided 21 juvenile male rats born 26-28 days into experimental and control groups, and gave them free drinking of monosaccharide solution and ordinary filtered water under the same food feeding.
Among them, the monosaccharide solution mass-to-volume ratio is 11%, containing 65% fructose and 35% glucose, and the ratio simulates the sugary drinks commonly drunk by humans.
The mice were monitored three times a week for food intake, solution intake, and body weight.
When the mice reach adulthood, that is, after they have grown to 60 days, they begin to experiment with memory tasks.
The first experiment is the NOVEL (Novel Object in Context) experiment, which measures hippocampus-dependent episodic memory function based on mice's ability to recognize familiar things in a particular environment.
Specifically, it provides two different environments: a translucent box and a gray opaque box.
Place 2 different objects A and B in a translucent box on the first day and put the mice into it to become familiar;
The next day put the mice in a gray box and replace B with A, i.e., place two identical objects A;
On the third day, the objects in the gray box were replaced by A and B, both of which the mice had seen, but at this time one of the objects was placed in a position that had not been seen before for the mice.
It is then possible to record the time it takes the mice to explore the "new" object divided by the sum of the time spent exploring objects A and B, known as the "discrimination index" (assuming the mice spend more time on unfamiliar objects).
Identification and exploration are defined as sniffing with the nose or touching objects with the front paws.
The second experiment, the NOR (Novel Object Recognition) experiment, measures basic cognitive memory functions that are independent of the hippocampus and controlled by the cerebral cortex by comparing the time it takes mice to explore new things unrelated to the environment.
Specifically, the mouse is placed in a space and given two identical jars for the mouse to explore; then the space is fully cleaned and disinfected, one of the objects is replaced, and the mouse is put in to record their exploration time of the two jars.
As a result, the performance of the two groups of mice in the NOR experiment did not differ much, but the results of the NOIC experiment were different:
Compared with mice that grew up drinking white water in their infancy, mice that drank too much sugar water spent more time exploring familiar object B, that is, their ability to remember it became weaker.
△ CTL stands for white water, sug for sugar water
This also shows that high glucose intake in the early stages of life development has no effect on the memory function dependent on the cerebral cortex, but it will impair the contextual episodic memory function dependent on the hippocampus.
Among them, sequencing of mouse hippocampal RNA shows that a high-sugar diet mainly affects four pathways related to the prominent signaling of neurotransmitters: dopaminergic, glutamatergic, cholinergic, and serotonergic signaling pathways.
Mechanisms are difficult to find, intestinal flora
Why is that?
As the saying goes, "Quantum mechanics; mechanisms are hard to find, gut microbiota" – scientists extracted the feces of mice and began to find answers from their gut flora.
It turned out that sugary drinks really have an effect on the gut microbiota:
The concentrations of two Bacteroides species in the intestines of mice grown up drinking sugar water that were negatively correlated with hippocampal function: Bacteroides dii and Bacteroides d. josephus and Bacteroides d. Josephus increased.
The higher the concentration of these two bacteria, the stronger the damage to the hippocampus.
In addition, considering the effect of high sugar intake on weight, scientists have also done some targeted experiments.
The results were somewhat unexpected, and the mice had no effect on weight in adulthood by overstepped sugar intake during "adolescence."
However, their tolerance to glucose is reduced (the effect is that they are prone to diabetes).
Hey, although sugar can make people happy, it seems that it is better to touch less from a young age.