A study conducted by researchers from the University of Southern California found that consumption of junk food during adolescence can lead to long-term memory impairment in adulthood.

The neurotransmitter acetylcholine plays a role, as it is crucial to memory, as well as other brain functions like attention and learning. Consuming junk food also increases a child’s risk of depression, obesity and inflammatory conditions like eczema, rhinitis and severe asthma.

The report recommends that adults should set an example for children and encourage them to shift to healthier food choices, despite junk food being designed to be addictive.

Many parents are aware of the negative effects of alcohol and drugs on their children’s brains and take the necessary steps to protect them from these dangerous substances. However, there’s another stealth element that could be putting them at high risk of future memory issues – and it’s likely in your kitchen pantry right now.

The study conducted by researchers from the University of Southern California found that consuming a junk food diet during adolescence can lead to long-term memory impairment in adulthood. Even more alarming is that the effects could be irreversible.

The featured animal study, published in the journal Brain, Behavior and Immunity, sought to determine the effects of feeding a junk food diet on adolescents’ brains. While conducting the study, the researchers considered previous findings that a poor diet can lead to Alzheimer’s disease.

They found that the neurotransmitter acetylcholine plays a role, as it is crucial to memory, as well as other brain functions like attention and learning. People who have been diagnosed with Alzheimer’s disease tend to have lower levels of this neurotransmitter in their brains.

The researchers then wondered if adolescents who consumed the same type of processed food diet – loaded with unhealthy fats and refined sugar – could also experience similar effects, especially as their brains are still going through significant development.

To test their hypothesis, they fed one group of rats a “junk food cafeteria-style diet” consisting of potato chips, chocolate-covered peanut butter cups and soda, and gave a control group a standard diet.

They then observed the animals’ acetylcholine levels and analysed their brain responses by having them undergo tasks to test their memory. One test involved allowing the subjects to explore new objects in different scenarios. After a few minutes, they repeated the test but added a new object to the scene.

The researchers observed that the rats who ate the junk food diet were unable to recall which objects they had seen before, as well as their location. The control group, however, was more familiar with their surroundings.

In a Study Finds article, Anna Hayes, a postdoctoral research fellow who is a member of the research team, explained: “Acetylcholine signalling is a mechanism to help them encode and remember those events, analogous to ‘episodic memory’ in humans that allows us to remember events from our past. That signal appears to not be happening in the animals that grew up eating the fatty, sugary diet.”

This isn’t the first study that showed the negative effects of a junk food diet on your brain.

A 2012 study published in the Journal of Psychology found that just six weeks of bingeing on sweets and sweetened beverages could slow brain function, memory and learning – to put it simply, it makes you “stupid.”

In a UCLA article, Fernando Gomez-Pinilla, a professor of neurosurgery at the David Geffen School of Medicine and one of the study authors, said: “Our findings illustrate that what you eat affects how you think. Eating a high-fructose diet over the long term alters your brain’s ability to learn and remember information.”

A 2023 study published in Cell Metabolism also revealed that junk foods like chips can cause the brain to “rewire” itself, and subconsciously learn to opt for foods that are loaded with fat and sugar. Considering that adolescence is a very sensitive time for a child’s developing brain, these findings should be a cause for concern.

Scott Kanoski, a professor of biological sciences at the University of Southern California (USC) Dornsife College of Letters, Arts, and Sciences and co-author of the feature study, comments: “What we see not just in this paper, but in some of our other recent work, is that if these rats grew up on this junk food diet, then they have these memory impairments that don’t go away.

“I don’t know how to say this without sounding like Cassandra and doom and gloom, but unfortunately, some things that may be more easily reversible during adulthood are less reversible when they are occurring during childhood.”

In the US, an estimated five million teens aged 12 to 17 – or 20 per cent of the overall age group – have experienced at least one episode of depression, with symptoms of a loss of interest in daily activities and struggling with sleep, energy and appetite.

Depression among teens has increased by 30 per cent in the last 10 years, and while many aspects are being considered, one potential factor could be eating junk food or a fast-food diet.

According to a study from researchers at the University of Alabama at Birmingham, two dietary elements could be contributing to depression in adolescents: having high levels of sodium and low levels of potassium.

High sodium levels are associated with salty snacks and fast-food items like fries and burgers, while having low potassium levels means there aren’t enough potassium-rich foods in the diet, including fruits and vegetables. These can influence neurotransmitters and neural function.

“Given the substantial brain development that occurs during adolescence, individuals in this developmental period may be particularly vulnerable to the effects of diet on the neural mechanisms underlying emotion regulation and depression,” the researchers said.

Healthy eating habits begin at home, and as adults, we must set an example for children and encourage them to shift to healthier food choices. However, this can be difficult, since junk food has been designed to be addictive.

• A Tell / The Defender report / By Joseph Mercola