Gut Microbiota: How it Affects Your Mood, Sleep and Stress Levels

The gut microbiota is the community of bugs, including bacteria, that live in our intestine. It has been called the body’s “forgotten organ” because of the important role it plays beyond digestion and metabolism.

You might have read about the importance of a healthy gut microbiota for a healthy brain. Links have been made between the microbiota and depression, anxiety and stress. Your gut bacteria may even affect how well you sleep.

But it can be difficult to work out exactly how far the science has come in this emerging field of research. So what evidence is there that your gut microbiota affects your brain?

How does your gut talk to your brain?

When you’re healthy, bacteria are kept safely inside your gut. For the most part, the bacteria and your gut live in harmony. (The gut has been known to nurture or even control the behaviour of the bacteria for your well-being.)

So how do the bacteria get their signal out?

The best evidence is that the normal channels of communication from your gut are being hijacked by the bacteria.

The gut has a bidirectional relationship with the central nervous system, referred to as the “gut-brain axis”. This allows the gut to send and receive signals to and from the brain.

A recent study found that the addition of a “good” strain of the bacteria lactobacillus (which is also found in yoghurt) to the gut of normal mice reduced their anxiety levels. The effect was blocked after cutting the vagus nerve – the main connection between brain and gut. This suggests the gut-brain axis is being used by bacteria to affect the brain.

This link was clarified in a study where bacterial metabolites (by-products) from fibre digestion were found to increase the levels of the gut hormone and neurotransmitter, serotonin. Serotonin can activate the vagus, suggesting one way your gut bacteria might be linked with your brain.

There are many other ways gut bacteria might affect your brain, including via bacterial toxins and metabolites, nutrient-scavenging, changing your taste-receptors and stirring up your immune system.

A recent study found that the addition of a “good” strain of the bacteria lactobacillus (which is also found in yoghurt) to the gut of normal mice reduced their anxiety levels.

How can the gut affect your mental health?

Two human studies looked at people with major depression and found that bacteria in their faeces differed from healthy volunteers. But it’s not yet clear why there is a difference, or even what counts as a “normal” gut microbiota.

In mouse studies, changes to the gut bacteria from antibiotics, probiotics (live bacteria) or specific breeding techniques are associated with anxious and depressive behaviours. These behaviours can be “transferred” from one mouse to another after a faecal microbiota transplant.

Even more intriguingly, in a study this year, gut microbiota samples from people with major depression were used to colonise bacteria-free rats. These rats went on to show behavioural changes related to depression.

Stress is also likely to be important in gut microbiota and mental health. We’ve known for a long time that stress contributes to the onset of mental illness. We are now discovering bidirectional links between stress and the microbiota.

In rat pups, exposure to a stressor (being separated from their mums) changes their gut microbiota, their stress response, and their behaviour. Probiotics containing “good” strains of bacteria can reduce their stress behaviours.

How gut microbiota affects your mood

Medical conditions associated with changes in mood, such as irritable bowel syndrome (IBS) and chronic fatigue syndrome (CFS), might also be related to gut microbiota.

IBS is considered a “gut-brain disorder”, since it is often worsened by stress. Half of IBS sufferers also have difficulties with depression or anxiety.

Ongoing research is investigating whether gut bacteria are one reason for the mood symptoms in IBS, as well as the gastrointestinal pain, diarrhoea and constipation.

Similarly, CFS is a multi-system illness, with many patients experiencing unbalanced gut microbiota. In these patients, alterations in the gut microbiota may contribute to the development of symptoms such as depression, neurocognitive impairments (affecting memory, thought and communication), pain and sleep disturbance.

In a recent study, higher levels of lactobacillus were associated with poorer mood in CFS participants. Some improvements in sleep and mood were observed when patients used antibiotic treatment to reduce gut microbial imbalance.

The exact contributions of stress and other factors such as intestinal permeability (which allows nutrients to pass through the gut) to these disorders are not understood. But the downstream effects seem to be involved in IBS, inflammatory bowel conditions, CFS, depression and chronic pain.

How our gut affects our sleep

Our mental health is closely linked to the quality and timing of our sleep. Now evidence suggests that the gut microbiota can influence sleep quality and sleep-wake cycles (our circadian rhythm).

A study this year examined patients with CFS. The researchers found that higher levels of the “bad” clostridium bacteria were associated with an increased likelihood of sleep problems and fatigue, but this was specific to females only. This suggests that an unbalanced gut may precipitate or perpetuate sleep problems.

There is emerging evidence that circadian rhythms regulate the gut immune response. The effect of immune cells on the biological clock could provide insights into the possible bidirectional relationship between sleep and the gut. For example, data from animal studies suggests that circadian misalignment can lead to an unbalanced gut microbiota. But this effect can be moderated by diet.

There is growing concern that disruptions to our circadian timing of sleep leads to a range of health issues, such as obesity, metabolic and inflammatory disease, and mood disorders. This is particularly important for shiftworkers and others who experience changes to their sleep/wake patterns.

For example, data from animal studies suggests that circadian misalignment can lead to an unbalanced gut microbiota. But this effect can be moderated by diet. 

What this means for treatment

In terms of using interventions directed at the gut to treat brain disorders – so called “psychobiotics” – there is a lot of promise but little clear evidence.

Probiotic (live bacteria) treatments in mice have been shown to reduce cortisol, an important stress hormone, and decrease anxious and depressive behaviours.

But there are very few studies in humans. A recent systematic review of all the human studies showed the majority do not show any effect of probiotics on mood, stress or symptoms of mental illness.

On the plus side, large studies show us that people who eat a balanced diet with all the usual good stuff (fibre, fresh fruit and vegetables) have lower rates of mental illness as adults and adolescents.

Clearly, diet affects both the gut microbiota and mental health. Research is ongoing to see whether it is a healthy gut microbiota that underlies this relationship.

A healthy gut microbiota is linked to a healthy brain. However there are only a handful of human studies demonstrating real-world relevance of this link to mental health outcomes.

There is still a way to go before we can say exactly how best to harness the microbiota in order to improve brain function and mental health.

This article originally appeared on The Source and was written by By 

Paul Bertrand, RMIT University, Amy Loughman, RMIT University, Melinda Jackson, RMIT University

7 Ways To Instantly Stimulate Your Vagus Nerve To Address Inflammation, Depression And Migraines

The vagus nerve (found right behind where you typically feel for your pulse) is the longest nerve in your body.

It is one of 12 cranial nerves and it extends from your brainstem all the way to your abdomen and through various organs including your heart, esophagus, and your lungs.

It is sometimes called “cranial nerve X,” as it forms part of your involuntary nervous system that directs all of the unconscious body actions, like stabilizing your heart rate and making sure your digestive tract is working properly.

Interestingly, the vagus nerve was named because it actually “wanders” like a “vagabond” and sends out tiny fibres from your brainstem to your visceral organs (organs in your chest and abdomen—heart, lungs, liver, pancreas and intestines.)

The vagus nerve essentially controls your entire parasympathetic nervous system (the system responsible for stimulating what is known as your “rest-and-digest” or “feed and breed” activities when your body is resting and after eating.)

A study done at The Feinstein Institute for Medical Research has shown that the vagus nerve may actually be what they call “the missing link” to treating chronic inflammation that can cause a variety of other issues— like high blood pressure, migraines, digestive issues and any inflammatory related things like arthritis etc.—all without medication!

Your Vagal Tone

Vagal tone essentially refers to the inhibitory control of your vagus nerve over your heart rate. What the studies now show is that vagal tone is key to activating your parasympathetic nervous system and everything it does. We can measure your vagal tone by tracking your heart rate in combination with your breathing rate.

Typically, when you breathe in, your heart rate speeds slightly and vice versa when you breathe out. Your vagal tone is then determined by the difference between your inhalation heart rate and your exhalation heart rate—the bigger the difference, the higher your vagal tone, which is actually good in this case because it means that you are more able than someone with a lower vagal tone, to relax your body after a stressful situation.

Why a higher vagal tone is good

Apart from being able to relax faster after stress, people with a high vagal tone have overall better functioning internal systems including:

• Better blood sugar regulation
• Decreased risk of stroke and cardiovascular disease
• Generally lower blood pressure
• Better digestion due to proper production of digestive enzymes
• Fewer migraines
• Less depression
• Less anxiety (they naturally deal with stress better)

What scientists have discovered is that the vagus nerve constantly monitors your gut microbiome to determine if there are any pathogenic organisms, and if so, it initiates a response that then controls any inflammation that results from these foreign organisms, which can affect your mood, your stress levels (and your ability to cope with the stress) and your overall inflammation levels.

What if I have low vagal tone?

Unfortunately, people with a low vagal tone are more prone to hearts problems and strokes, diabetes, chronic fatigue syndrome, depression, cognitive impairment, not to mention more inflammatory conditions such as any autoimmune diseases like thyroid issues, rheumatoid arthritis, inflammatory bowel disease, endometriosis, lupus etc.

So, how do I increase my vagal tone?

So far, researchers have stimulated the vagus nerve using a device that emits an electrical current but there are other ways to do this yourself.

While the studies also reveal that people are genetically predisposed to different levels of vagal tone, with consistent practice, you can alter your tone to some degree using the following methods.

1. Humming

You know all of those people you used to think were “new age” because they would sit quietly and repeat the “OM” sound? Well, it turns out they are on to something. Because the vagus nerve is connected to your vocal cords, systematic humming can stimulate the nerve.

2. Speaking

Likewise, people who speak more are more likely to be able to raise their vagal tone as talking is done through the vocal cords. Singing and laughter in general will also do the trick.

3. Wash your face with cold water

A splash of cold water does seem to stimulate the vagus nerve. Whenever your body is required to adjust to the cold, your fight-or-flight (sympathetic) system declines and your rest-and-digest (parasympathetic) system increases. (1)

In other words, any kind of sudden cold exposure will increase vagus nerve activation. You can achieve this by either dipping your face in cold water or take a cold shower.

4. Breathing deeply using your diaphragm

Breathing long, deep breaths from your diaphragm can stimulate and tone your vagus nerve.

5. Yoga

Research shows that yoga, along with breathing practices, can significantly increase your vagal tone.

6. Meditation

According to a 2010 study, people who meditate regularly and think more positive thoughts tend to have better vagal tone.

7. Increase Good Gut Bacteria

While there are countless benefits to increasing the healthy bacteria in your gut, surprisingly, this also helps to create a positive “feedback loop” through your vagus nerve and thus increase its tone. Probiotics are a good source of healthy bacteria.

All of the above methods are beneficial to your overall health simply for the fact that they also help reduce stress, which is a major factor in disease, but also knowing that you can help improve your vagal tone, and the specific issue of inflammation, is a powerful tool.

Add these simple tips to your daily routine and see how much better you feel in a relatively short time.

sources:

• http://mosaicscience.com/story/hacking-nervous-system
• http://kripalu.org/blog/thrive/2012/08/30/why-yoga-works/
• http://www.nytimes.com/2014/05/25/magazine/can-the-nervous-system-be-hacked.html?_r=1
• Forsythe P, Bienenstock J, Kunze WA.Vagal pathways for microbiome-brain-gut axis communication. Adv Exp Med Biol. 2014;817:115-33.
• Kok, B, Fredrickson, B, Coffey, K, et al. How Positive Emotions Build Physical Health: Perceived Positive Social Connections Account for the Upward Spiral Between Positive Emotions and Vagal Tone. Psychological Science 2013 24: 1123

This article originally appeared on dailyhealthpost.com

Early-Life Exercise Alters Gut Microbes, Promotes Healthy Brain

The human gut harbors a teeming menagerie of over 100 trillion microorganisms, and researchers at the University of Colorado Boulder have discovered that exercising early in life can alter that microbial community for the better, promoting healthier brain and metabolic activity over the course of a lifetime.

The research, which was recently published in the journal Immunology and Cell Biology, indicates that there may be a window of opportunity during early human development to optimize the chances of better lifelong health.

"Exercise affects many aspects of health, both metabolic and mental, and people are only now starting to look at the plasticity of these gut microbes," said Monika Fleshner, a professor in CU-Boulder's Department of Integrative Physiology and the senior author of the new study. "That is one of the novel aspects of this research."

Microbes take up residence within human intestines shortly after birth and are vital to the development of the immune system and various neural functions. These microbes can add as many 5 million genes to a person's overall genetic profile and thus have tremendous power to influence aspects of human physiology.

While this diverse microbial community remains somewhat malleable throughout adult life and can be influenced by environmental factors such as diet and sleep patterns, the researchers found that gut microorganisms are especially 'plastic' at a young age.

The study found that juvenile rats who voluntarily exercised every day developed a more beneficial microbial structure, including the expansion of probiotic bacterial species in their gut compared to both their sedentary counterparts and adult rats, even when the adult rats exercised as well.

The researchers have not, as of yet, pinpointed an exact age range when the gut microbe community is likeliest to change, but the preliminary findings indicate that earlier is better.

A robust, healthy community of gut microbes also appears to promote healthy brain function and provide anti-depressant effects, Fleshner said. Previous research has shown that the human brain responds to microbial signals from the gut, though the exact communication methods are still under investigation.

"Future research on this microbial ecosystem will hone in on how these microbes influence brain function in a long-lasting way," said Agniezka Mika, a graduate researcher in CU-Boulder's Department of Integrative Physiology and the lead author of the new study.

Going forward, the researchers also plan to explore novel means of encouraging positive gut microbe plasticity in adults, who tend to have stable microbial communities that are more resistant to change.

The National Institutes of Health (NIH) supported this research.

The above post is reprinted from materials provided by University of Colorado at Boulder. Note: Materials may be edited for content and length.