At one time or another, we’ve all had that groggy morning experience telling us that we’ve not slept well. Maybe its stress on the job or too many late nights. Whatever the cause, we do our best to shake the cobwebs from our brain, rub our bleary eyes and soldier on through the day. We tell ourselves to hold on until bedtime and a second chance at a good night’s sleep.
But what if that second chance never comes and that groggy, restless feeling is a common, every day experience? And if sleep-deprived, brain-fog is an everyday experience, how would you even know that something’s wrong? In fact, you wouldn’t because the dial you use to measure the performance of your body has been adjusted downward and now you begin to forget details that were easily retained in the past. Or the agitation and feelings of unease you have are common and an accepted part of life.
Chronic sleep deprivation results in any number of maladies including emotional distress, memory loss, over-eating, obesity and other long-term diseases. Our decision-making and problem solving skills are greatly diminished when we consistently do not get the sleep we need.
Most experts recommend seven to nine hours of sleep for healthy adults and there is good reason for that; quality sleep helps to protect mental and physical health. During sleep your body recovers from the wear and tear of everyday life and your brain is preparing for the next day. Studies show that a good night’s sleep promotes emotional wellbeing and improves your ability to learn, remember, react and interact with others. Without sleep our bodies do not recover and we are forgetful, clumsy, emotionally unstable, grumpy and anxious.
Intuitively we believe that our bodies know how much sleep it needs. As if somehow, despite the constant bombardment of negative environmental factors, our bodies simply cope and will give us the sleep we need. We believe that our bodies know when to fall asleep and when to wake up. But, is that really true? And how much of an impact does our environment play? After all, our bodies take cues from the multitude of molecular signals that course through our systems on a constant basis; molecular signals that are influenced by the stress we feel and the food we eat.
Hormones and neurotransmitters such as serotonin, dopamine, melatonin and cortisol all play critical roles in regulating mood and sleep patterns. These and other molecular signals are the real sleep conductors and they dictate whether or not you get a good night sleep. These signals interact with the “master clock” located in an area of the brain called the suprachiasmatic nucleus. The “master clock” controls our circadian rhythms that dictate the physical, mental and behavioral changes, including our sleep-wake cycles, that follow a 24-hour time frame, responding primarily to light and darkness.
So what controls circadian rhythms and what can we do to ensure our individual “master clocks” are operating at peak performance? Scientists have been interested in this question for many years and recent discoveries have highlighted a critical role for the trillions of microorganisms that occupy our intestines, known as the gut microbiota.
The microorganisms in our intestines are masters at interacting with our bodies through the expression of molecular signals that influence immune response, mood changes, and even our sleep-wake cycles. There are anywhere between 100-1,000 different species of bacteria in our intestines and each one of us has a unique combination of different species. It is interesting to note that on the DNA-sequence level, our human genomes are 99.9% similar to each other, yet our microbiome (i.e., the genetic make-up of the microbiota) is so unique that it is only approximately 10-20% similar to the next person.
Your individual microbiota community is influenced by the environment that you choose to create for it. When you eat healthy foods and exercise regularly you create an environment that promotes positive interactions between the gut microbiota and the body. It’s important to note that the microbial community in your gut does not change easily. Studies have shown that the microbiota is resilient to change and it can take months of healthy eating to realize changes in gut microbiota composition. However, within our personal gut microbiota, where trillions of microorganisms interact with each other and the gut environment, fluctuations occur in community composition and gene-expression in a circadian-dependent manner.
Recent scientific research has demonstrated that when laboratory mice are fed high-fat, western diets, noticeable shifts occur in the microbial-dependent metabolites that are produced in the gut following digestion of food. These metabolites are then shuttled to the liver and ultimately result in the disruption of hepatic circadian rhythm networks. Certain microbial metabolites, such as short-chain fatty acids, that contribute to healthy circadian rhythms were lowered while other unhealthy microbial metabolites, such as hydrogen sulfide, were elevated. Furthermore, these shifts in microbial metabolites as a result of a high-fat, western diet caused lowered metabolic states and diet-induced obesity.
Additional work in this area is needed to further understand the environmental and host-specific cues that influence our internal “master clocks”. However, it is clear that the microorganisms in our gut and the metabolites that they produce have an important role in maintaining a healthy circadian rhythm to ensure proper sleep-wake cycles. It is also equally clear that a healthy microbiota is promoted by a diverse and healthy diet. So, in the end, our ability to get the sleep we need is closely intertwined with the activities of our gut microbiota, which in turn, is molded by the food we eat and other healthy lifestyle activities.
Promoting a diverse gut microbiota is important for good health. Scientific research, as described here, demonstrates the important role that our gut microorganisms play in maintaining a healthy sleep-wake cycle. By taking steps to eat healthy, exercise on a regular basis and supplement diets with proven probiotic strains, we give our bodies a better chance at a good night’s sleep.
Leone, V., et. al., 2015. Effects of Diurnal Variation of Gut Microbes and High-Fat Feeding on Host Circadian Clock Function and Metabolism. Cell Host & Microbes 17: 681-689.
About the author:
Douglas Toal, PhD is a Clinical Scientist with extensive knowledge and expertise in medical laboratory sciences, metabolism and anti-aging medicine.