Category: Memory

A study shows that “good” or healthy fats and “bad” fats affect brain cells in different ways.

Diets rich in saturated fat and or refined carbohydrates are linked to neurodegenerative disorders, neuroinflammation, and cognitive dysfunction.

In contrast, diets rich in polyunsaturated fats such as omega-3 and omega-6 fatty acids may have neuroprotective and anti-inflammatory effects.

A study shows that “good” or healthy fats and “bad” fats affect brain cells in different ways.

The research suggests that high-fat diets will reduce polyunsaturated fatty acids and increase saturated fatty acids in the hippocampus.

The hippocampus is part of the brain important for the formation of new memories and learning processes.

The finding may explain the connection between high-fat foods and memory impairment, especially in older people.

Moreover, the study found that omega-3 DHA (docosahexaenoic acid) has the ability to reduce the negative effect of high fat foods-induced inflammation in brain cells.

Previously they showed that eating highly processed foods was linked to higher levels of inflammation in the brain accompanied with memory loss, but DHA supplements averted the issue.

DHA can lower inflammation by acting directly on microglia in response to issues such as traumatic brain injury, neurodegenerative disorders including Alzheimer’s, and brain infections.

Microglia are types of immune cells that are involved in brain development, and inflammatory responses to brain injury.

Dr Ruth Barrientos, the study’s senior author, said:

“The cool thing about this paper is that for the first time, we’re really starting to tease these things apart by cell type.

Our lab and others have often looked at the whole tissue of the hippocampus to observe the brain’s memory-related response to a high-fat diet.

But we’ve been curious about which cell types are more or less affected by these saturated fatty acids, and this is our first foray into determining that.”

DHA protects cells

For this study, microglia cells from animal tissue were taken and developed in the laboratory.

Then these microglia models were exposed to palmitic acid, the most common saturated fat in foods such as shortening, pork, beef, lard, palm oil, and cocoa butter.

The results revealed that palmitic acid caused changes in gene expression involved in the inflammatory response.

However, DHA treatment completely prevented or partially lowered alterations and so protected cells against inflammation.

Dr Michael Butler, the study’s first author, said:

“Previous work has shown that DHA is protective in the brain and that palmitic acid has been detrimental to brain cells, but this is the first time we’ve looked at how DHA can directly protect against the effects of palmitic acid in those microglia, and we see that there is a strong protective effect.

The protective effects of DHA might, in this context, be restricted to effects on gene expression related to the pro-inflammatory response as opposed to the metabolic deficits that the saturated fat also induced.”

Related

• Eating just one meal that is high in saturated fats ruins the ability to concentrate.
• Dry eye syndrome can be an outcome of omega-3 fatty acids deficiency.
• The right balance between omega-3 and omega-6 fatty acids promotes healthy cognitive aging.
• A higher intake of fibre and lower intake of saturated fats can reduce belly fat.
• A mother who eats a high-fat diet can cause life-long changes in the brain of her child.

The study was published in the journal Frontiers in Cellular Neuroscience (Butler et al., 2023).

This fact about memory might seem depressing, but it is critical to useful recall.

Recalling one memory actually leads to the forgetting of other competing memories, a study confirms.

It is one of the single most surprising facts about memory, now isolated by neuroscience research.

Although many scientists believed the brain must work this way, it has been demonstrated.

Dr Maria Wimber, a cognitive neuroscientist and the study’s first author, said:

“Though there has been an emerging belief within the academic field that the brain has this inhibitory mechanism, I think a lot of people are surprised to hear that recalling memories has this darker side of making us forget others by actually suppressing them.”

The study monitored people’s brain activity while they tried to recall images they had been shown earlier.

By measuring activity in tiny sections of the brain, the neuroscientists were able to track individual memories.

They found that as one memory was recalled, others were suppressed.

Each subsequent time a target memory was recalled, it became stronger, while the others became weaker.

Dr Michael Anderson, a neuroscientist who co-led the study, said:

“People are used to thinking of forgetting as something passive.

Our research reveals that people are more engaged than they realize in shaping what they remember of their lives.

The idea that the very act of remembering can cause forgetting is surprising, and could tell us more about selective memory and even self deception.”

The process is believed to be critical to how memory and learning work.

Here’s how I’ve explained it previously:

“The idea that forgetting helps you learn seems counter-intuitive, but think of it this way: imagine if you created a brain that could remember and recall everything.

When this amazing brain was trying to remember where it parked the car, it would immediately bring to mind all the car parks it had ever seen, then it would have to sort through the lot.

Obviously the only one that’s of interest is the most recent.

And this is generally true of most of our memories.

Recent events are usually much more important than ones that happened a long time ago.

To make your super-brain quicker and more useful in the real world you’d have to build in some system for discounting old, useless info.

In fact, of course, we all have one of these super-brains with a discounting system: we call it ‘forgetting’.”

Dr Wimber suggested another situation in which forgetting is useful:

“Forgetting is often viewed as a negative thing, but of course, it can be incredibly useful when trying to overcome a negative memory from our past.

So there are opportunities for this to be applied in areas to really help people.”

He continued:

“It has significance for anything that relies on memory, but a really good example is that of eyewitness testimonies.

When a witness is asked to recall specific information about an event, and they are quizzed time and time again, it could well be to the detriment of associated memories — giving the impression that their memory is sketchy.

In fact, the repeated recall is causing them to forget these details.”

The study was published in the journal Nature Neuroscience (Wimber et al., 2015).

The rapid damage done to the brain by eating these foods is surprising.

Eating a diet of highly processed foods could seriously damage your memory, a study on rats suggests.

A diet high in foods like soft drinks, chips, candy, ice-cream and packaged soups is linked to neuroinflammation and cognitive problems.

However, the omega-3 fatty acid DHA almost completely reverses this effect — even in older rats.

Foods high in DHA include salmon, trout, oysters, cod and canned tuna.

The rapid damage done to the brain by eating highly processed foods is surprising, said Dr Ruth Barrientos, study co-author:

“The fact we’re seeing these effects so quickly is a little bit alarming.

These findings indicate that consumption of a processed diet can produce significant and abrupt memory deficits—and in the aging population, rapid memory decline has a greater likelihood of progressing into neurodegenerative diseases such as Alzheimer’s disease.

By being aware of this, maybe we can limit processed foods in our diets and increase consumption of foods that are rich in the omega-3 fatty acid DHA to either prevent or slow that progression.”

The study on rats fed some of them a standard diet or one that mimicked the highly processed diet that many people around the world now consume.

A third group were given the highly processed diet along with DHA supplementation.

Eating a highly processed diet caused inflammation in critical areas of the brain, including the hippocampus and amygdala.

Dr Barrientos explained:

“The amygdala in humans has been implicated in memories associated with emotional—fear and anxiety-producing—events.

If this region of the brain is dysfunctional, cues that predict danger may be missed and could lead to bad decisions.”

The hippocampus, meanwhile is vital for memory.

Rats fed the highly processed diet subsequently demonstrated memory loss, unless they were given DHA supplementation.

Prevention is better than cure, though, and highly processed foods are unhealthy in many ways, warned Dr Barrientos:

“These are the types of diets that are advertised as being low in fat, but they’re highly processed.

They have no fiber and have refined carbohydrates that are also known as low-quality carbohydrates.

Folks who are used to looking at nutritional information need to pay attention to the fiber and quality of carbohydrates.

This study really shows those things are important.”

The study was published in the journal Brain, Behavior, and Immunity (Butler et al., 2021).