In past studies using animals, Highly processed diets are linked to memory impairment and inflammation in the aging brain – and Effects can be seen quicklyafter just 3 days of terrible eating.

New research suggests that another dietary pitfall, a lack of dietary fiber, may have similar detrimental effects in the short term in older adults.

Studies in rats also point to the amygdala, a small structure that governs emotional memories, especially those associated with bad experiences, as a brain region that is particularly sensitive to highly processed diets. Sophisticated diets of all kinds fed to older animals were associated with cellular and behavioral signs of cognitive problems that trace back to the emotional memory centers of the brain.

“The amygdala is important for learning the association between something scary and a bad outcome, and we found that it doesn’t matter whether all sophisticated diets are high fat, high sugar, low fat, or low sugar; they all impair memory, which is controlled by the amygdala,” said the co-first author. Ruth Barrientosinvestigator. Institute of Brain, Behavior, and Immunology at Ohio State University.

“And when we looked at what all of these diets had in common, what became very clear was that they all lacked fiber.”

Barrientos, also an associate professor, said not learning the connection between actions and their consequences, especially when they are dangerous or dangerous, can increase the risk of physical or economic harm. Psychiatry and behavioral health and neuroscience at the Ohio State Medical University.

“The amygdala plays a role in such cognition and learning,” she says. “Therefore, that vulnerability to refined diets is of concern for older adults who: Increased risk of financial exploitation and fraud. ”

This study was recently published in the journal brain, behavior, immunity.

Dr. Barrientos has been studying the effects of high-fat and highly processed diets on the brains of older adults for several years, observing behavioral outcomes and associated signs of inflammation in both the amygdala and hippocampus, which are important for spatial, autobiographical, and episodic memory.

In this study, she and her colleagues focused on understanding the diet to see whether fat, sugar, or something else had the strongest association with cognitive impairment in rats.

Young and old male rats were fed normal chow or one of five experimental diets for 3 days. Low fat, high sugar. Medium fat, low sugar. Medium fat, high carbohydrate. Or high fat, low sugar.

Behavioral tests showed that old animals fed a completely refined diet, regardless of fat or sugar levels, had impaired amygdala-based long-term emotional memory compared to young rats fed the same diet. In contrast, memory-related behaviors traced back to the hippocampus were only negatively affected by a high-fat, low-carbohydrate diet.

And there was also the factor of not using fibers. All experimental diets contained no fiber, and testing of the rats’ intestines and blood showed that Butyrateproduced in the intestines when dietary fiber is broken down by intestinal microorganisms, and circulates in the blood.

Previous studies by other labs have shown that butyrate has anti-inflammatory properties and can cross the blood-brain barrier, which could mean that butyrate deficiency caused by a lack of dietary fiber could be linked to uncontrolled inflammation in the brain, Barrientos said.

“What our study really reveals is the complexity of diet and how it affects a variety of things, and even the brain,” co-lead authors said. kedryn baskinAssistant Professor Physiology and cell biology at Ohio State University. “There’s no silver bullet, but in this case it’s low butyrate due to lack of fiber.”

Researchers found the most convincing evidence of sophisticated diet-related damage at the cellular level. mitochondria Microglia, cells with multiple functions important for memory function. When exposed to experimental energy demands in cell culture, mitochondria in young brains were able to adapt to the changes, but these power centers in aging brain cells were unable to rise to the challenge.

“The mitochondria are still functioning, but their respiration is reduced, and older people have a much lower rate of function than younger people,” Baskin said.

Although refined diets caused some weight gain, Barrientos said the findings dispel the idea that obesity caused by highly processed diets is the main cause of cognitive impairment.

“The effects on the brain after eating something occur pretty quickly,” she says. “You can experience this unhealthy cognitive dysfunction long before you become obese.”

And while she and Professor Baskin said the data suggested that increasing fiber in the diet could be beneficial for the brain, the research team said they planned to study whether supplementing animals with fiber and butyrate could reverse age-related cognitive problems associated with poor diets.

This research was supported by the National Institute on Aging, the National Center for the Advancement of Translational Sciences, the Ohio State Healthy Food Research Initiative, and the National Heart, Lung, and Blood Institute.

Additional co-authors are Michael Butler, Jade Blackwell, Andrew Sanchez, Hannah Saunders, Dominick Coloney, Jefferson Jantsch, Stephanie Muscat, Sabrina Mackey Alfonso, and Brian Alvarez, all of Ohio State University. Maria Elisa Caetano Silva, Akriti Shrestha, Casey Kin Yun Lim, Robert McCusker, and Jacob Allen from the University of Illinois at Urbana-Champaign;