Keto Diet and Hypoxia Alter Gut Microbiota, Leading to Cognitive Impairment

A newly published paper tackles the discovered activities found in the gut microbiota. These changes happening in the region of the gut could potentially affect the brain and behavior of living organisms, including humans.

The study on how the microbes in the gut work and the key goals of this process were presented by the experts from the University of California, Los Angeles.

Microbiomes and Hippocampus

The microbes, according to the investigation, are microorganisms that can trigger and aggravate cognitive impairment because of their effects on a specific region in the brain, deep inside the temporal lobe that is responsible for learning and memory, also known as the hippocampus.

The gut microbiota of mice served as the model for the observation. According to the study, one group of bacteria increased significantly when the mice were fed a type of diet that includes low carbohydrates but is high in fat rate called the ketogenic diet. The bacteria that increased in concentration is known as Bilophila and can possibly cause poor oxygen distribution throughout the system that leads to hypoxia.

The application of the combined effects between processes and bacteria, including hypoxia, the ketogenic diet, and Bilophila wadsworthia, heavily impacted the hippocampus and eventually impaired the subject's cognitive ability.

Cognitive Decline: Mouse Experiment Shows Cognitive Impairment in Microbiome, Hypoxia, and Ketogenic Diet Combination

The experiments included two separate groups for testing, including the subjects that had a normal diet and the other that had a ketogenic diet. Technology Networks reported that throughout the test, both groups were purposely given low oxygen levels for five days but were given a chance to recover for the following four days.

Cognitive impairment is correlated with the lack of oxygen, and the latter is essential to apply to the subjects to mimic the perfect conditions happening during cognitive impairment. The findings under these circumstances could provide us answers on the reasons of cognitive impairment specifics caused by aging, as well as neurological diseases.

The mice subjects were also allowed to go through a challenging maze to test whether they will be able to navigate with their current cognitive ability and type of diet. The group that took the normal diet had a higher success rate on escaping the maze compared to the group with the ketogenic diet. The difference in escaping rate between the two groups ranged from 25%-75%.

The diets alone were also tested in the investigation to find whether they could single-handedly affect the cognitive ability of the subjects that were not deprived of oxygen supply. The results did not find any change in the subjects, and they were still able to escape the maze regardless of the diet they were treated. This eliminates the idea of cognitive impairment in diet alone but established that cognitive ability only fails when combined with the lack of oxygen.

The last experiment included the depletion of microbiota in mice subjects before applying the ketogenic diet and hypoxia. The group that had microbiota depletion alone was determined to have a higher escaping rate than the group exposed to a ketogenic diet and hypoxia and had no changes in their microbiota levels.

UCLA expert and lead author of the study Christine Olson said that the findings from their observation highlighted the defining factors that could affect cognitive behavior in mice.

In conclusion, the ketogenic diet and hypoxia dictate how the microbes will impact the brain and lead to cognitive impairment. The study was published in the journal Cell Host & Microbe, titled "Alterations in the Gut Microbiota Contribute to Cognitive Impairment Induced by the Ketogenic Diet and Hypoxia."

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