Junk food damages the brain to such an extent that it permanently affects memory

Reading time: 2 minutes – seen in the New Atlas.

The impact of unhealthy food on physical and mental health is increasingly being documented. These often ultra-processed, high-fat foods contribute to the development of obesity, type 2 diabetes and cardiovascular disease, as well as early cognitive decline (anxiety, depression, Alzheimer’s disease, etc.). It is associated with every fifth death in the world – or 11 million deaths per year.

Many of the effects of unhealthy food are usually reversible. However, new research published by New Atlas suggests that the effects on memory if consumed during adolescence are too great to be negated by a healthy diet.

The scientists based their observations on two groups of rats, one of which was fed an unbalanced diet during childhood and adolescence before switching to a healthy diet as adults. Experiments were then conducted to test their episodic memory (the memory of personally experienced moments that allows them to locate themselves in time and space and project themselves into the future).

Alzheimer’s-like symptoms

First, all rats were presented with objects in different locations. A few days later they were introduced there again, but with an additional object. While those who ate a normal diet recognized the scene, those who ate junk food showed no signs of memory.

It all comes down to the secretion of one chemical: acetylcholine. This neurotransmitter (a type of molecule that allows messages to pass between neurons) plays an important role in the proper functioning of the hippocampus, an area of ​​the brain responsible for, among other things, memory and learning. Low levels of acetylcholine are especially common in patients with Alzheimer’s disease.

Thus, consuming a diet high in fat and processed foods between the ages of 10 and 24 (and especially during adolescence) may harm brain development by interfering with the proper secretion of acetylcholine. In rats, switching to a healthy diet had no restorative effect: the effects of unhealthy food could only be reversed by using drugs that mimic the corresponding neurotransmitter.

If this study helps to better understand the relationship between unhealthy foods and cognitive decline, research must now focus on ways to reverse effects that are a priori difficult to reverse… and determine whether these effects are also observed in humans.