Intestinal Flora Archives – Chronobiology.com

Newly Discovered Immune System Mechanism Links Sleep and Gut Health

Oct. 17, 2019

If you work nights or experience other conditions that prevent you from getting good sleep in the evening hours, research has shown that you are at a greater risk of developing a weakened immune system. Now, a new study has discovered that the immune system may also play a pivotal role in the relationship between sleep and gut health, increasing the importance of a good night’s sleep.

Immune System Influences Relationship Between Sleep and Gut Health

Not getting enough restorative sleep may open the door to a number of different diseases via the effect of lack of sleep on the immune system, according to a recent study on sleep and gut health.

It has long been recognized that a lack of nighttime sleep opens us up to a greater number of medical conditions. People who work nights or graveyard shifts are significantly more likely to develop cancer, ulcers, obesity and a long list of other illnesses, which suggests that the circadian rhythm plays a role.

In the most recent study, researchers working out of Portugal’s Champalimaud Centre for the Unknown wanted to see if the lymphoid immune cells (ILC3 cells) that help the body fight off infection were influenced by the body’s circadian rhythm. Using mice, the team found that ILC3 cells were very sensitive to changes in the circadian rhythm. In fact, they noted that there was a circuit in the brain that directly connects the circadian rhythm to the ILC3 cells in the gut.

When the body’s biological clock is disrupted by changes to the normal cycle of light and dark, the ILC3 cells are also affected, disrupting the entire gut microbiome as well as the body’s lipid absorption rate. In short, a dysregulated circadian rhythm resulted in changes to both metabolic health and intestinal inflammation. When the circadian rhythm is disrupted regularly, the researchers found that it resulted in fewer ILC3 cells in the gut microbiome. This led to higher instances of inflammation throughout the body and an increased risk of obesity.

Normally, there is a protein that tells the ILC3 cells where to go to help protect the body. However, disrupting the sleep patterns and altering the circadian rhythm prevents this protein from functioning properly. As a result the ILC3 cells don’t know where to go and the immune system is weakened. This may explain why people with irregular sleep patterns also take longer to heal or recover from sickness.

How Does Sleep Affect Gut Health?

We’re just beginning to learn that there’s a relationship between sleep quality and the health of the gut microbiome. This is a reciprocal relationship, meaning a deficiency on one end will result in a deficiency in the other. In 2016, researchers tested this relationship in a study that used nine male subjects. The subjects were in good physical condition, had not experienced any sleep disorders and consumed regular diets.

When the participants were deprived of sleep for just two nights, the researchers noted some significant changes in their health: They found that the test subjects had experienced a drop in the amount of healthy bacteria in their gut microbiomes. There was a notable increase of the bacteria that affected obesity and type 2 diabetes as well. Finally, they noted that the body of each participant exhibited decreased insulin sensitivity.

That relationship works in the opposite direction as well. Studying subjects aged 50 to 85, researchers in another study looked at how a compromised gut microbiome affected sleep and cognitive functioning. They discovered that a healthier and more diverse gut microbiome resulted in subjects getting better-quality sleep. Their cognitive functioning was also improved, although it’s difficult to say whether this was directly related to gut microbiome diversity or to getting a good night’s sleep. Better sleep and more bacterial diversity may have played equal parts in helping subjects improve their cognitive functioning. While more research is needed, it’s clear that a healthy gut microbiome does affect sleep quality just as sleeping habits influence the health of the gut microbiome.

Sleep and Immunity

In other research, it was found that the quality and duration of sleep can also affect the functioning of the immune system. This is because the immune system releases proteins called cytokines during sleep, which affect the body’s ability to fight off illnesses and infections. If you’re not sleeping well, your body won’t produce a sufficient amount of cytokines, which means you’ll have a greater risk of developing inflammation or infections.

While you’re sleeping, your body is working hard to repair the strain or damage that you experienced throughout your waking hours. This means sending out antibodies to help reduce inflammation and tissue damage. The body needs seven to eight hours of sleep each night to accomplish this task, so by failing to get enough sleep, you’re also hampering this process. This is why you feel more fatigued and less productive when you don’t get enough sleep.

Over time, you build up a sleep deficit, leaving your immune system in an extremely weakened state. As a result, you’ll feel more stressed and you’ll be more prone to develop illnesses or infections. The relationship between sleep and immune system functioning also explains why people working night shifts are more likely to contract colds or the flu. The link between sleep and immunity further explains why getting enough sleep every night is essential to overall health.

Intermittent Fasting Affects Circadian Rhythm, Says New Study

Jan. 23, 2019

Dietary fads seem to come and go with the seasons. Fasting, particularly intermittent fasting, seems to be here to stay. A growing number of people are achieving weight loss and other health goals using this simple method of eating. According to new research, this may be due to the way intermittent fasting affects circadian rhythm. Could this style of eating be right for you?

Intermittent Fasting: More Than a Diet Fad

Fasting is one of the world’s oldest practices, used both for health and religious reasons over several millennia. Ascetics routinely gave up food and even water for days in search of meaningful change and insight. Intermittent fasting is slightly different from traditional fasting because people give up calories for shorter, well-defined periods of time. In the most popular type of intermittent fasting, users fast for 16 hours of the day and eat for the remaining eight.

The benefits of this style of eating are many, which is why it is steadily growing in popularity. People often lose dramatic amounts of weight, even when eating similar amounts of calories. Many people have seen their blood pressure and cholesterol lowered to safe and healthy levels. People with type 2 diabetes and other metabolic diseases also appear to have benefits. Even people who are otherwise healthy report positive health effects, such as increased energy, better sleep and improved digestive health.

How can simply changing the times when you eat have such dramatic health benefits? According to new research, the secret lies in the effects of intermittent fasting on the body’s internal clocks.

How Intermittent Fasting Affects Circadian Rhythm

Our diet, especially the times when we eat, can affect our circadian rhythm in a variety of ways. Food stimulates insulin production, which in turn can activate different genes linked to internal clocks. In addition, eating stimulates our internal microbiome, the bacteria that live in our digestive tracts. These bacteria in turn release hormones and other biochemicals that can stimulate wakefulness or sleepiness.

According to new research, intermittent fasting may affect health and circadian clocks in more dramatic and previously unknown ways. Researchers looked at how periods of fasting affected mice.

Researchers divided mice into two groups: one that was placed on an intermittent fasting diet and one that had food available all the time. These mice ate the same amount of calories and fats. Despite this, the unrestricted eating group gained weight rapidly while the intermittent fasting group did not.

Muscle cells have two different modes to acquire energy. When glucose from food is readily available, insulin “unlocks” cell receptors so it can flood into muscle cells and power their activities. When glucose is in short supply, the liver produces ketones from fatty acids, which are then used to fuel muscle. Producing ketones causes a distinct shift in the metabolism of cells throughout the human body. Its effects on the circadian rhythm are particularly dramatic.

Mice who underwent intermittent fasting had larger oscillations in the activity of the genes that govern circadian rhythm. This means that they were biochemically primed to sleep better during their sleeping periods and were more wakeful during the day. Researchers believe that this is due to the effects of ketones on certain circadian genes. Regardless of the cause, it is apparent that intermittent fasting can lead to a stronger and more rhythmic circadian rhythm.

Circadian Rhythm and Health

This study offers new information on how intermittent fasting can have such dramatic effects on weight and health. Having a dysregulated circadian rhythm is a risk factor for major diseases, including heart disease and diabetes. It also can contribute to fatigue and a wide variety of unpleasant daily symptoms. Everyone prefers to feel sleepy at night and alert during the day, which requires having properly functioning internal clocks.

However, keeping a healthy circadian rhythm can be difficult in the modern world. Many people work odd hours or have commitments that keep them from sleep. Screens and ambient light are almost ubiquitous, which can affect our ability to make the important sleep hormone melatonin. Although we all want to have the benefits of a well-regulated circadian rhythm, it can be difficult to maintain.

Is Intermittent Fasting Right for You?

Intermittent fasting appears to have dramatic health effects, including an impact on our internal clocks. However, this does not mean it is right for everyone. Fasting can very difficult in the beginning, before your body becomes used to eating on a different schedule. In addition, you should talk to your doctor if you have any health issues, as fasting may require medical supervision initially for some people. Although intermittent fasting can be challenging in the beginning, it appears to have whole body health effects that can make it more than worth the effort.

Disrupting Gut Bacteria Circadian Rhythm Leads to Serious Health Consequences

Aug. 15, 2018

The gastrointestinal microbiome and its effects on human health have been all over the media lately. While we have known for hundreds of years that there are bacteria in our gut, we are just beginning to grasp their diversity and complexity. Some recent studies have focused on the circadian rhythm of these tiny bacteria. Like all living creatures, gut bacteria have internal clocks that govern a variety of important biological processes. Our own actions can knock the gut bacteria circadian rhythm out of sync, with serious consequences to human health.

The Inner Life of Your Gut

Your gastrointestinal tract is lined with billions of bacteria. Although we are not physically aware of these microbes, they affect our health in a variety of ways. In addition to assisting in digestion and the absorption of key nutrients, our gut bacteria help to regulate our immune system and can impact most of our organs.

All organisms have a circadian rhythm. Although our internal clocks are innate, they can be influenced by external cues. For humans, sunlight and temperature both serve as powerful cues. For the gut bacteria circadian rhythm, our own actions make up the majority of the environmental cues. Some bacteria respond to hormones such as melatonin that are released according to our own internal clocks. Others respond to the presence of food in the GI tract.

Our microbiomes are constantly in flux. As we go through the day, the number of different kinds of bacteria can change dramatically. In addition, their location in our gut also can differ based on timing. We have co-evolved to have a symbiosis, in which our gut bacteria help us to maintain good health and vice-versa.

What Happens When Your Gut Bacteria Circadian Rhythm is Out of Sync?

Many humans live dysregulated lives, eating at a wide variety of times and sleeping whenever we get the chance. This affects our bodies in many ways, but also can affect the organisms that live symbiotically with us. This in turn can have further effects on our health. When our microbiome gets off track, the impact can be far-reaching.

Researchers have used a variety of techniques to learn more about the link between our gut bacteria circadian rhythm and our own health. In one experiment, Israeli researchers measured levels of different enzymes in the bloodstream over the course of a day. Liver enzymes, which are crucial for detoxification of the body, vary widely over a standard 24-hour day. When mice were fed at different times of day than they were used to, their microbiome and liver enzymes became more dysregulated. When the microbiome was further disrupted using antibiotics, their liver enzyme production was so dysregulated that the mice were unable to handle high doses of common medications such as Tylenol.

In addition to affecting the function of key organs such as the liver, our gut bacteria appear to impact our own circadian rhythm. A few smaller studies have suggested that our circadian rhythms respond to the chemicals released by gut flora, similar to how they respond to our own melatonin.

The Endless Effects of Circadian Rhythm Disruption

Our own circadian disruption can affect the internal clocks of our gut bacteria, which in turn further disrupt our own circadian rhythm. It is easy to see how this could create a self-perpetuating cycle of health effects. This is especially relevant in modern times, when a variety of factors make it difficult to keep our bodies on their natural timing.

The modern Western diet and other factors in contemporary life already place our gut flora at risk. At the same time, it is more difficult than ever to keep our internal clocks on track. More people have jobs that include shift work or late hours. We are chained to smartphones and other devices that release a wavelength of light that has been proven to disrupt our circadian rhythm. Even if you can control your life to allow optimal sleep, light pollution is serious enough to interfere with your sleep.

The disruption of our circadian rhythms and gut microbiome can be devastating. However, there are ways to keep your body well-regulated.

Keeping Your Internal Clocks — And Those of Your Gut Bacteria — On Track

Keeping your body and your microbiome regulated in the modern world can be a challenge. However, there are several ways to accomplish this. Consider the following tips:

Practice basic sleep hygiene, going to bed and waking at the same time and turning off screens well before bedtime.
Use blackout curtains to keep out ambient light if this is a concern in your area.
Eat meals at the same time every day, to ensure that your gut flora are not dysregulated.
Take probiotic and prebiotic supplements to ensure that the right bacteria can thrive in your GI tract.
Avoid taking antibiotics or using antimicrobial products unless completely necessary for your health.

There is still much to discover about the ways that gut bacteria interact with our circadian rhythm. However, it is clear that modern people face an uphill battle in maintaining the right balance. Although it can be difficult to keep your internal clocks, and those of your microflora, on track, doing so is crucial to your health and well-being.

Why Fasting Boosts Gut Health

May. 16, 2018

Intermittent fasting has become the new health trend, with several different plans that feature short-term calorie restriction offering a variety of benefits. While some people write off fasting as just another dieting fad, a growing body of research is showing interesting health effects. According to a new study, fasting boosts gut health and may even function as a metabolic reset button.

Fasting: Just a Fad?

Fasting has been used for millennia for spiritual effects. However, it is becoming popular in modern times not as a way to get in touch with your higher nature but as a natural way of improving whole body health.

There are several types of fasting, from short term (12-24 hour) calorie restriction to longer fasts. All have one thing in common: They deprive the body of food long enough that the body switches its style of metabolism. Instead of burning glucose to fuel our cells, the body burns fat to produce ketones. This changes the way our cells function on a basic biochemical level.

Although this may sound like “woo,” it appears to have a variety of positive health effects. Studies have found that fasting and even very short term calorie restriction can slow down aging, reduce levels of oxidative stress, and reduce the effects of common chronic illnesses. In addition, a new study suggests that fasting may affect gut bacteria, increasing amounts of positive microbes while decreasing bacteria that cause illness.

The Microbiome and Metabolism

Humans are never truly alone. We share our bodies with trillions of bacteria that colonize our skin, eyes, and digestive tract. People with an imbalance of these bacteria suffer a variety of negative effects, from digestive tract disorders to depression. In addition, the microbiome appears to have a variety of effects on our metabolism.

Beneficial gut bacteria are essential to effective digestion. They break down certain vitamins and nutrients so they can be efficiently absorbed. These microbes also release hormones that improve the way we use insulin, reduce hunger and improve metabolism. Several metabolic diseases such as diabetes have been linked to changes in the microbiome.

In addition to being a very effective weight loss plan, fasting changes the way our body interacts with food, improving the efficiency of our mitochondria. In addition, it may improve health by changing the makeup and the activity of the bacteria that line our gastrointestinal tracts.

How Fasting Boosts Gut Health

Can fasting change your microbiome and thus your whole body health? New research suggests that even short periods of calorie restriction change the makeup of your microbiome, with beneficial bacteria becoming more dominant. These bacteria in turn release hormones that actually communicate with the brain, helping to improve metabolism on a cellular level.

In addition, fasting appears to improve the activity of stem cells in the digestive tract. Young people have ample amounts of stem cells that differentiate to become new cells to replace damaged or dysfunctional ones. As we age, our bodies lose the ability to repair tissues due to a decrease in these stem cells. Any improvement in stem cell function can decrease the long term damage and loss of function associated with aging.

When we fast, our stem cells also switch to metabolizing fats rather than glucose. This change has been called a “metabolic switch” because it can have far-reaching effects on our metabolism and our health. According to new research, this may make stem cells more active and effective, particularly ones in our GI tract. This in turn can prevent some of the gradual damage that makes aging people more prone to intestinal problems.

Secrets to Healthy Fasting

Modern fasting is not merely a matter of giving up food for a certain time period. Healthy fasting requires special measures. For example, it is important to not become deprived of nutrients or protein. Many people who use intermittent fasting successfully eat high protein meals before and after the desired fasting period. In addition, it is important to take vitamins or eat vitamin-rich foods to keep levels of these essential elements high.

In addition, there are other ways to support a healthy microbiome. Researchers and doctors recommend eating fermented foods that are rich in lactobacillus and other beneficial bacteria. In addition, taking a probiotic and prebiotic supplement will help your microbiome diverse and healthy.

Our ancestors underwent intermittent fasting during times of famine. While we often view this as negative, it appears that our bodies are designed to work optimally with short term periods of calorie restriction. Introducing short periods of fasting into your life may help to improve your metabolism, reduce aging and help you to lead a generally healthier life.

Seasonal Changes in Gut Bacteria Reveal Impact of Diet on the Microbiome

Mar. 07, 2018

A great deal of research has shown that our gastrointestinal flora are important and even crucial to our health. We now know that our physical and mental health can be impacted immensely by the trillions of bacteria living in our gut. This can be a mixed blessing, considering that the modern Western diet does not support a healthy balance of the bacteria we need to enjoy optimal well-being. In addition, new research on hunter-gatherer tribes shows that we may not be undergoing seasonal changes in gut bacteria that are a natural part of the human life cycle.

Why Study Hunter-Gatherer Tribes?

Hunter-gatherers were the original human civilizations, subsisting on plant and animal foods available in the environment rather than participating in agriculture and other modern means of acquiring resources. These tribes still exist, although they are becoming increasingly rare. Although they have high infant mortality and accidental death due to the dangers of a wild environment, they also have incredibly low rates of chronic illness and other diseases that plague humans who live in modern settings. In fact, if hunter-gatherers can avoid various traumas and infectious diseases, they usually live astoundingly long and healthy lives.

Recent studies have shown that gut flora are crucial to our health and that our diet and environment are important in sustaining this. As a result, researchers have been intensively studying hunters and gatherers to get information on our natural gastrointestinal balance.

Seasonal Changes in Gut Bacteria in Hunter-Gatherer Tribes

Researchers looked at the diet and GI flora of the Hadza tribe, a group of hunter-gatherers living in rural Tanzania. Like most hunter-gatherers, this tribe has a cyclical diet that varies by availability in each season. In a place and culture without supermarkets, eating in-season is the only option. During the rainy season, the tribe enjoys fresh berries and honey. In the dry season, they eat more wild game. Some foods, such as certain types of starchy tuber, are available all year round.

Researchers took samples from the bowel movements of traditional Hadza members throughout the year to analyze their GI flora. There were surprising changes in not just their natural flora, but in their enzyme balance as well. A species known as Bacteroides was more common during the dry season, as were certain enzymes used to process plant foods. In addition, there was a more diverse range of bacteria during the dry season. Researchers plan to study more about seasonal variations in the Hadza diet to link their traditional foods to the cycles in bacteria and enzymes.

Industrialization and Gut Health

This is the first study to find seasonal changes in gut flora; researchers are currently unsure of whether these cycles occur in modern people to some extent. However, this is not the first study to show that the GI flora of hunter-gatherers is very different from that of people in the industrialized world. Although people in developed areas enjoy easy and ample access to a variety of foods, our diets may not be optimal for our gastrointestinal health.

Hunter-gatherers have gut bacteria that is rare or unheard of in the modern world. For example, they have colonies of Treponema bacteria, which are absent in people who live in industrialized areas. A lack of Treponema bacteria has been linked to Crohn’s disease, which does not exist in hunter-gatherers. In addition, hunter-gatherers have a much larger variation in gut bacteria, with more species than we have. The takeaway? Some of the differences in our diet and thus our GI flora may be having a negative impact on our health.

Maintaining a Healthy Gut

Although there is still much to learn about gut bacteria and their effect on our health, it is clear that our inner flora is important to our health. Maintaining healthy gut flora can be difficult in the industrialized world. However, there are several things you can do to improve your gastrointestinal health:

Eat fermented and cultured foods that contain live bacteria.
Avoid antibiotics and antimicrobials except where necessary for your health.
Eat more soluble fiber, which feeds beneficial gut bacteria.
Take a supplement that has both probiotics and prebiotics.

Modern people have more chronic illness than the world has ever known. This may be partially due to an imbalance of bacteria living in our guts that is caused by poor eating habits and over-exposure to antibiotics. Although it can be difficult to change our habits, achieving a healthier and more diverse range of gut bacteria may be an important part of living a healthy lifestyle.

Intestinal Flora