Dear bacteria, sleep and brain health

This paper is part of the NMJ special edition 2018 on cognition and mental health. Download the full edition here.

reference

Anderson JR, Carroll I, Azcarate-Peril Ma, et al. A preliminary examination of intestinal microbiota, sleep and cognitive flexibility in healthy older adults. sleep medicine . 2017; 38: 104-107.

Study goal

evaluation of relationships between intestinal microbiota, sleep quality and cognitive flexibility in healthy older adults.

draft

a preliminary observation study

participant

data from 37 participants aged 50 to 85 (73 % female, 92 % Caucasians) were analyzed. People with significant neurological or gastrointestinal diseases were excluded, as were people who had taken probiotics or antibiotics within 30 days before the study. The presence of high blood pressure, diabetes and sleep apnea was pursued as covariates, as was the food intake of macronutrients per participant report (Epic-Norfolk Food Frequency Questionnaire).

target parameter

The self -reported sleep quality was rated with the Pittsburg Sleep Quality Index (PSQI), which pursued the sleeping and duration. Higher values ​​in the PSQI indicate poorer sleep quality. The cognitive flexibility was evaluated by Stroop-op color word tests. During the Stroop test, the participants read color words ("Stroop word") loudly, identified the ink color of rows of XS ("Stroop-color") and identified the ink color of incongruent color words ("Stroop-color word") as quickly as possible. Higher values ​​indicate better identified elements. Dearmicrobiom samples were analyzed by ubiome using 16S-ribosomal RNA amplic conference and specified as a percentage of the existing phyla.

important knowledge

under control of the covariates correlated a reduced sleep quality with poorer stroop test results (Stroop Word, p = 0.018; stroop color word, p = 0.010 and stroop color, p = 0.053). Here, too, the study under the control of the covariates participants with a higher percentage of Verrukomikrobie had improved cognitive flexibility, measured with Stroop Word ( p = 0.034) and stroop color ( p = 0.071) tests. The lentiphaerae tribe did not show a similar correlation; However, there was a stronger relationship with the performance of Stroop Color-Word ( p = 0.015), regardless of sleep quality.

practice implications

As the increase in research in microbiota suggests, the potential influence of the intestinal microbiota on our understanding of human health and our approach to the treatment of different health conditions is enormous. Although this special study is easily confused by the number of variables discussed, together with their admitted restrictions (e.g. results that are more based on observations than causal relationships, lack of detailed screening measures for sleep and superficial research of the mechanism of action), it delivers some interesting thought for thought: could be a factor, sleep quality and Cognitive health connects?

observation studies, such as those discussed here, are the first steps in a direction that can ultimately help us to make the manipulation of the microbiome usable for therapeutic purposes.

In view of the fact that more than 30% of Americans report on nightly lack of sleep and an estimated 50 to 70 million adults of a sleep disorder, ^{1 A continuous research of modifiable factors is a necessity. The intestinal microbioma is a largely unexplored area, and our journey to recognize its effects on the health requirements is just at the beginning. The influence of the intestinal microbioma on human health must be understood deeply. Observation studies, such as those discussed here, are the first steps in a direction that can ultimately help us to make manipulation of the microbiome usable for therapeutic purposes.}

The researchers suggest that their results together with those from other related studies ^{2-4 indicate that the sleep quality is directly proportional to the presence of certain phyla of the intestinal microbiota, which then correlate with the cognitive function. Both Phyla discussed in this article were associated with sleep disorders. The verrukomicrobie was then directly with cognition while correlated lentiphaerae was possibly correlated indirectly. The not so clear question was whether the cognitive impairment was a direct result of an impaired intestinal flora or whether it is secondary to the chronic, non -transferable health states that are also associated with both, such as obesity, diabetes and heart disease.}

The researchers failed to discuss the possible reverse correlation, in which the microbiota shares of the specified phyla are poor lentiphaerae and Verrocumicrobia could be a direct cause of reduced sleep quality. We know that sleep quality is directly related to chronic diseases and cognitive decay; The Centers for Disease Control and Prevention show that adults who sleep less than 7 hours a night are more likely to report chronic health problems than those who get enough sleep. ^{5 Due to the observation design of this study, it is not possible to draw direct cause-effect consequences. With increasing recognition of the intestinal brain connection in the community, the relationship between these two variables should perhaps be considered dynamic and bidirectional.}

The pronounced correlation shown in this study between the verrukomicrobia and lentisphaerae phyla and sleep quality is in contrast to a study by Benedict and colleagues from 2016, which showed a correlation with other phyla than this. associated genres and species not part of the probiotics seen and prescribed more frequently today. All of this should say that this information is certainly fascinating, but we are at the very beginning to understand how the microbiota of the intestine can (or not) influence sleep and perception.