Sugar Intake Tied to Memory Problems in Adolescent Rats

An animal study suggests that adolescents were at an increased risk of suffering from the detrimental health effects of sugar-sweetened beverages.

Sugar-sweetened beverages (SSBs) are drinks that are sweetened with sugar, high-fructose corn syrup or other caloric sweeteners. Public health experts have identified sugar-sweetened beverages as a major contributor to poor diet and increasing rate of obesity worldwide. Studies have even shown that the daily consumptions of these beverages impair the ability to learn and remember information, especially if the consumption occurs during adolescent period.

Further investigating the effects of sugar-sweetened beverage consumption, the researchers at the University of Southern California studied rats as model subjects and found that these beverages increase the risk of suffering from negative health effects.

As part of the study, 76 adolescent rats were given access to sugar-sweetened beverages that replicate the concentrations found in soft drinks.

It was observed that the adolescent rats which freely consumed large quantities of liquid solutions with sugar or high fructose corn syrup (HFCS) experienced memory problems and brain inflammation and also became pre-diabetic. Neither did the adult rats who took the sugary drinks experience the problems, nor did the adolescent rats who did not consume sugar.

"The brain is especially vulnerable to dietary influences during critical periods of development, like adolescence," said Scott Kanoski, corresponding author of the study and an assistant professor at the USC Dornsife College of Letters, Arts and Sciences.

Nearly 30-40 percent of the rats' caloric intake came from sugar or HFCS. Added sugar make up to 17 percent of the total caloric intake of teens in the United States on an average, reports the CDC. The rats were later tested again in mazes that reviewed their spatial memory ability.

The researchers observed that the adolescent rats that took sugar beverages, mainly HFCS, did worse in the test as compared to any other group; which may be due to the neuroinflammation detected in the hippocampus, the region of the temporal lobe that is located deep within the brain that regulated memory formations.

Those with Alzheimer's and other forms of dementia are known to have a damaged hippocampus.

"Consuming a diet high in added sugars not only can lead to weight gain and metabolic disturbances, but can also negatively impact our neural functioning and cognitive ability." Kanoski said.

Next, the team plans to investigate how different monosaccharides (simple sugars) and HFCS affect the brain.

The finding was documented in the journal Hippocampus.