Western diet may permanently harm developing brains’ ability to remember things.

1. A high-sugar, high-fat diet, like junk food or the Western diet, has been linked to long-term memory problems in rats, according to a recent study.
2. It is believed that these meals interfere with the hippocampus’s ability to function, which is important for memory in both rats and humans.
3. The fact that this memory impairment persisted even after the rats were fed a healthy diet may be the most alarming discovery.

The human brain is particularly sensitive as it develops toward adulthood during childhood and adolescence.

According to a recent study conducted on rats by researchers at USC Dornsrife in California, brain damage induced by junk food that is high in fat and sugar, or a typical Western diet, is particularly likely to occur at this stage.

The study’s authors looked at how these foods affected acetylcholine (ACh) levels in the brain, a neurotransmitter that’s crucial for memory, learning, arousal, and attention. Low levels of ACh have been linked to the development of Alzheimer’s diseaseTrusted Source

Juvenile and adolescent rats were fed a variety of meals during the study. They could have as much of the high-fat, high-sugar food, potato chips, peanut butter cups, and high-fructose corn syrup as they wanted. They could also drink water at will.

A control group of rats was given access to only ordinary chow and water.

When the rats reached young maturity, they were given memory tests. Every rat was exposed to new environments and things. A few days later, the rats were placed back in same locations along with one additional item. The experimental group didn’t seem to realize anything had changed, but the control group showed curiosity about that object.

The experimental groups’ memory deficits continued even after they were shifted to a healthy diet as adults, indicating possibly permanent brain injury.

The hippocampal regions of the experimental groups, which are strongly linked to memory and learning in both rats and humans, showed weakened ACh signaling, according to the researchers.

Published in Brain, Behavior, and Immunity is the study.

The Western diet causes hippocampal problems

The authors of the new study found that ACh signaling was disturbed in the hippocampus. Senior study investigator Scott Kanoski, PhD, MS, , a biological sciences professor at USC Dornsrife, provided Medical News Today with the following explanation:

One area of the brain that is especially vulnerable to biological and environmental stresses is the hippocampus. This is especially true when this brain region is still developing, which occurs during the juvenile and adolescent years.

“The rats’ hippocampi experienced acetylcholine disruption in our diet model, which is comparable to disruptions seen in Alzheimer’s disease.” To further understand how early-life dietary and metabolic factors impact long-term risk for Alzheimer’s disease and other linked dementias, more research is necessary, according to Kanoski.

Why growing brains are more susceptible

Not engaged in this study, Amy Reichelt, PhD, BSc with honors in Psychology,, has done a great deal of research on the impact of diet on the growing brain.

Reichelt stated that it would have been intriguing if the writers had also looked at how food affected cholinergic signaling in the prefrontal brain of adult and teenage rats.

She continued, “Changes may have been specific to the younger animals because this area of the brain is rich in ACh receptors and is also the last part of the brain to mature.”

According to Reichelt, ” “research with rodents that the prefrontal cortex [i]s susceptible to the detrimental effects of poor diets that are high in fat and sugar.” An important part of the brain for executive control abilities like impulse control and decision-making is this one.

“Brand new research conducted at SickKids also shows that the brains of children and adolescents with a higher BMI had different neuronal activity signatures associated with reductions in inhibition in the frontal cortex,  a similar cellular profile to rats that ate a Western-style diet Reichelt stated, listing humans as one of those animals.

Reichelt’s research is a pre-print and has not yet been accepted for publication in a peer-reviewed journal.

Permanent or long-lasting alterations to memory

Longitudinal studies conducted on humans have demonstrated that midlife nutritional and metabolic variables (such as obesity and high-fat diets) can raise the risk of dementia later in life. But nothing is known about the possible connection to early life development, according to Kanoski.

More investigation is necessary to determine whether memory problems are irreversible. However, Kanoski observed that the rats’ memory did not get any better even after they were fed a healthy adult diet.

“It’s likely that these systems would have returned to normal if the healthy diet had been followed for a longer period of time. To comprehend the conditions under which these persistent deficiencies can be corrected, more research is required, he stated.

Enhanced memory using two medications

In a later stage of the study, the researchers did discover that the rats’ memory was recovered by injecting two medications, PNU-282987 and carbachol, straight into the hippocampus.

Furthermore, the study notes that a healthy diet can counteract the negative alterations to the  gut microbiome  that result from a Western or junk food diet. There might be memory implications to this as well.

According to Reichelt, “it is intriguing to include microbiome analysis in young animals because it has been demonstrated that the microbiota communicates with the brain through the secretion of neuroactive chemicals.”

The health effects of Western diets

Reichelt outlined the potentially dangerous aspects of the highly processed, high-fat, and high-sugar Western diet.

According to research, a high sugar diet is especially bad for memory function because it reduces hippocampus neurogenesis, which is the growth of new neurons in a crucial section of the brain needed to construct memories, Reichelt said.

As an illustration, Reichelt provided:

Specifically, when you drink high-sugar beverages like Coca-Cola, the sugar is quickly absorbed from your stomach into your blood, resulting in an increase in blood sugar levels. Insulin is then needed for the cells to absorb the glucose. Consuming sugar-sweetened beverages in excess can eventually lead to a blunting of insulin’s effectiveness, which can result in type 2 diabetes and metabolic syndrome (Trusted Source).

“Diets high in saturated fat, refined sugar, and  processed carbohydrates have been linked to long-term cognitive decline,” stated Michelle Routhenstein, MS, RD, CDCES, a preventive cardiology dietitian at EntirelyNourished.com who was not involved in the study.

Foods that strengthen memory

The perfect memory food, according to Reichelt, is eggs! A good supply of choline, which is a component of acetylcholine, is eggs, especially the yolk.

Apart from eggs, Routhenstein recommended that “foods rich in choline, such as fish — specifically omega-3 rich varieties found in salmon, sardines, and arctic char — nuts, and cruciferous vegetables like broccoli, cabbage, and Brussels sprouts may help to promote healthy acetylcholine signaling.”