Monday, March 6, 2017

Brain Rules: Your stomach bacteria partially controls your brain health

As unlikely as it seems, the bacteria in your digestive system influences some cognitive functions that are performed by the brain, including stress management and sleep cycles. If you haven’t considered them much before, then here are a few reasons why you should:

Probiotics, as defined by Ryan Andrews of Precision Nutrition, refers to any beneficial bacteria in our bodies. They’re plentiful in certain areas, such as our digestive tract, and help us absorb the nutrients from the food that we eat.
There’s another microbial level, which are prebiotics. Prebiotics serve as “food” for the beneficial bacteria in our body. As noted in the study “Dietary Prebiotics and Bioactive Milk Fractions Improve NREM Sleep, Enhance REM Sleep Rebound and Attenuate the Stress-Induced Decrease in Diurnal Temperature and Gut Microbial Alpha Diversity” and in a summary article by Science Daily, prebiotics are natural dietary fibers found in foods like artichokes, leeks, and onions.  
When the probiotics feed on this prebiotic fiber, the probiotics release metabolic substances as byproducts. These byproducts can then influence an organism’s brain function, as noted by Professor Monika Fleshner at the University of Colorado at Boulder in their Integrative Physiology Department.
The study used a rat model, feeding 3-week old male rats either standard feed or feed that included prebiotics. Then, they monitored the body temperatures, gut bacteria and sleep-wake cycles. The latter group spent more time in nonREM sleep than the non-prebiotic group. NonREM sleep is a crucial stage in the sleep cycle where cells regenerate and where the organism wakes up feeling the most rested.
In a second part of the experiment, the rats were exposed to a stimulus that caused a spike in cortisol, otherwise known as “stressing them out.”
The prebiotic group spent more time in REM sleep after the introduction of the stress stimuli, which is crucial for brains to “recover” after stress. Constant exposure to stress without proper recovery can lead to a decrease in healthy gut bacteria and abnormal fluctuations/stagnant body temperatures.
The study showed that the rats with the prebiotic supplement could continue sleeping well even after the stressor was added.
A different study, conducted at the University of Oxford’s Department of Psychiatry, found similar results. Dr. Phil Burnet of Oxford noted that when rats were given prebiotics repetitively, the number of molecules that increased and maintained healthy brain cells increased.
The molecule, as defined by Society for Neuroscience, is called Nerve Growth Factor, or NGF. Society of Neuroscience mentions that the neurotrophin brain-derived neurotrophic factor, or the BDNF, helps regenerate new neurons located in the hippocampus, which is the main memory center. The BDNF was also shown to increase in rats.
So, how can we use a study with a rat model to work on humans? It’s easier than expected. If you don’t have access to prebiotic or probiotic supplements, the shortcut would be to eat more foods that naturally contain probiotics.
Precision Nutrition lists yogurt, buttermilk, and bacterially cultured cheese as some examples. Most vegetables, fruits, and whole grains contain prebiotics, so eating foods from both bacterial groups can have positive effects on you just as much as the rats.
Consuming products with pre/probiotics can deepen sleep cycles and help the brain deal with long term, more serious mental states, such as depression, anxiety and PTSD.
After a stressful day at work, school or both, an extra amount of prebiotics can assist in REM sleep, which can help reset your brain for the next day. The effects aren’t instantaneous, but proper gut bacteria is just as good as any excuse to start that New Year’s Resolution of “eating right.
Anu Kumar is a sophomore in neuroscience and psychology and can be reached at akumar8@vols.utk.edu.

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