Home Medizin Der Verzehr von fetthaltigen Nahrungsmitteln vor der Operation kann bei älteren Erwachsenen Auswirkungen auf die gedächtnisbezogenen kognitiven Funktionen haben

Der Verzehr von fetthaltigen Nahrungsmitteln vor der Operation kann bei älteren Erwachsenen Auswirkungen auf die gedächtnisbezogenen kognitiven Funktionen haben

von NFI Redaktion

Eating high-fat foods in the days before surgery can trigger an intensified inflammatory response in the brain, impacting memory-related cognitive functions for weeks in older adults – and as new research on animals shows, even in young adults.

The study, building on previous investigations by the same lab at Ohio State University, also found that a one-month intake of DHA Omega-3 fatty acid supplement before the unhealthy diet and surgical procedure prevented the memory effects associated with the high-fat diet and surgery in both old and young adult rats.

Three days of a high-fat diet alone adversely affected a specific type of anxiety-related memory in older rats up to two weeks later – the same type of impairment observed in younger rats consuming fatty food and undergoing surgery. The team linked the brain inflammation behind these effects to a protein that activates the immune response.

„These data suggest that these multiple insults have a potentiating effect,“ said lead author Ruth Barrientos, researcher at the Ohio State Institute for Behavioral Medicine Research and associate professor of Psychiatry, Behavioral Health, and Neuroscience in the College of Medicine.

„We have shown that an unhealthy diet, even short-term, can have harmful consequences, especially when taken shortly before surgery and already triggering an inflammatory response. The high-fat diet alone may only slightly exacerbate brain inflammation, but then you have surgery, which does the same thing, and if put together in a short period, you get a synergistic reaction that can set things in motion for a problem with long-term memory.“

Ruth Barrientos, researcher at the Ohio State Institute for Behavioral Medicine Research

The study was recently published in the journal Brain, Behavior, and Immunity.

Barrientos‘ lab investigates how everyday events can trigger inflammation in the aging brain as the nervous system responds to signals from the immune system reacting to a threat. Decades of research have shown that with advancing age, there is a long-term „priming“ of the brain’s inflammatory profile and a loss of brain cell reserves to recover from.

The researchers fed young adult and older rats a diet high in saturated fats for three days before a procedure mimicking exploratory abdominal surgery – an event already known to cause cognitive problems for about a week in an older brain. Control rats ate regular feed and were anesthetized but did not undergo surgery. (Barrientos‘ lab has found that anesthesia alone in rats does not cause memory problems.)

In this study, the team, as in earlier investigations with old rats given morphine after surgery, found that an immune system receptor called TLR4 was the cause of brain inflammation and related memory problems caused by both surgery and the high-fat diet, said lead author Stephanie Muscat, clinical assistant professor of Neuroscience at Ohio State.

„Blocking the TLR4 pathway before the diet and surgery completely prevented this neuroimmune response and memory impairments, confirming this specific mechanism,“ said Muscat. „And as we had previously found in another unhealthy diet model, we demonstrated that DHA supplementation mitigated these inflammatory effects and prevented memory deficits after surgery.“

There were some surprising memory findings in the new work. Using different behavioral tasks, two types of memory were tested: contextual memory in the hippocampus and cued-fear memory in the amygdala. In contextual memory tests, rats with normal memory froze when re-entering a room where they had had an unpleasant experience. Cued-fear memory is evident when rats freeze in a new environment upon hearing a sound related to the previous bad experience.

In older rats in this study, the combination of a high-fat diet and surgery predictably led to problems in both contextual and fear memory, lasting at least two weeks – a more prolonged effect than researchers had previously observed.

The high-fat diet alone also impaired fear memory in aging rats. And in young adult rats, the combination of a high-fat diet and surgery only led to memory deficits due to anxiety but not problems with hippocampus-controlled memory.

„This tells us that in old animals, along with the fact that we also see the same impairment in young animals after the high-fat diet and surgery, the cued-fear memory is particularly vulnerable to the effects of diet. And we don’t know why,“ said Barrientos. „One of the things we hope to understand in the future is the vulnerability of the amygdala to these challenges of unhealthy diet.“

Given increasing evidence that fatty and highly processed foods can trigger inflammation-related memory problems in the brain of any age, there is converging evidence that DHA – one of the two Omega-3 fatty acids found in fish and other seafood and available in supplement form – plays a protective role that is compelling, said Barrientos.

„DHA was really effective in preventing these changes,“ she said. „And that’s amazing – it really suggests that this could be a potential pre-treatment, especially when people know they have to undergo surgery and their diet is unhealthy.“

This work was supported by grants from the National Institute on Aging and the National Institute of Neurological Disorders and Stroke.

Co-authors included Michael Butler, Menaz Bettes, James DeMarsh, Emmanuel Scaria, and Nicholas Deems, all from Ohio State.


Journal Reference:

Mascat, SM, et al. (2024). Postoperative cognitive dysfunctions worsened by high-fat diet via TLR4 and prevented by DHA supplementation. Brain, Behavior, and Immunity. doi.org/10.1016/j.bbi.2023.12.028.

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