Our ‘Second Brain’ – And Stress, Anxiety, Depression, Mood

Our 'Second Brain' - And Stress, Anxiety, Depression, Mood

Hidden in the walls of our digestive system is something extraordinary. Scientists have known about it for a while, but new technology is taking the research to the cutting edge. What is being discovered there will revolutionise the way we think about mental and physical health. 

What happens in our head has a lot to do with what’s happening further south, in what scientists affectionately call ‘the brain in our gut’. It has a strong connection to the brain in our head and together, they are key players in mood, and mental health.

The brain in our gut, or the second brain as it is also called, is made up of more 200-600 million neurons, arranged in the intricately folded tissue that lines the gastrointestinal tract. With firepower like that, it’s not surprising that the gut does so much more than deal with food and the messier parts of being human.

It plays a critical role in mental and emotional functioning by sending information to the brain and directly influencing things like feelings of stress, anxiety and sadness, as well as memory, decision-making and learning. The brain in our gut is not capable of thought as we know it, but it communicates back and forth with our main brain, playing a critical role in our mental and emotional well-being.

Unhappy mind. Unhappy belly. Which comes first?

It’s no secret that anxiety, stress and depression often bring unhappy bellies with them, by way of irritable bowel syndrome, constipation, diarrhea, bloating and pain. For decades, doctors thought that stress, anxiety and depression were the cause, but now it seems that it’s actually the other way around. Irritation in the gastrointestinal system seems to send signals to the brain that trigger mood changes. We know that probiotics seem to alleviate the symptoms of anxiety and depression and this might be why.

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The gut is not only important for physical health, it’s also critical for mental health. What’s fascinating is the direction of influence. The longest nerve exiting the brain is called the vagus (actually they are one pair of 12 pairs of nerves that run from the brain). It runs from the brainstem to the belly and touches the heart and most major organs along the way. Here’s the fascinating part. About 90% of the fibres in the vagus, carry information from the internal organs in the chest (such as the heart) and the abdomen to the brain, not the other way around. 

Our language holds evidence of this – we were talking about it well before we knew it. If you’ve ever been directed by ‘gut instinct’, ‘gone with your gut’ to make a decision, or ‘listened to your heart’, you’re likely getting signals from this second brain in your belly. 

Messages also travel the other way, from the brain to the heart and the gut, also via the vagus nerve but without a doubt, the main direction of information flow is from the gut to the brain. 

The Role of Gut Bacteria.

As well as neurons, there is another major player in the gut-brain connection – the 100 trillion bacteria that set up home inside your gut. According to professor of physiology, psychiatry and behavioral sciences at UCLA, Emeran Mayer, gut bacteria contains phenomenal wisdom that gets sent to the brain. They affect our behaviour every minute of every day from the day we are born, and possibly before.

A Fascinating Study: From Extroversion to Introversion via the Gut

Mayer’s research has shown how the specific combinations of bacteria in the gut might influence the wiring of the brain, and in turn affect such things as temperament, mood and learning. Other researchers have also explored a possible connection between gut bacteria and behaviour, and they’ve made some remarkable discoveries.

In one study, when the gut bacteria of timid mice was transferred into the gut of extroverted mice those extroverted mice became more anxious. It also worked the other way. When the timid mice received the gut bacteria of the bold mice, the timid mice because more bold and extroverted. Aggressive mice calmed down when scientists adjusted the their gut bacteria by giving them probiotics or antibiotics.

Another Study: The Connection Between Gut Bacteria and Temperament

Research has found correlations between temperament and the presence of specific intestinal bacteria in toddlers, particularly boys. The connection was independent of history of breastfeeding, diet and the method of childbirth. Here’s what they found:

  • The children with the most genetically diverse types of gut bacteria were more positive, curious, sociable and impulsive.
  • In boys, extroversion was associated with an abundance of particular types of bacteria (Rikenellaceae and Ruminococcaceae families and Dialister and Parabacteroides genera).
  • In girls, self-restraint, cuddliness and focussed attention were associated with a lower diversity of gut bacteria.
  • Girls with an abundance of a particular family of bacteria (Rikenellaceae) seemed to be more fearful than girls who had a more balanced diversity of microbes.

This research is still in its early days, so we still don’t know what a healthy tummy would look like in terms of the combination of gut bacteria, or what factors would influence this. It is possible that the perfect balance of microbiome will vary for all of us. For this reason, the researchers caution against trying to change a child’s gut microbiome just yet.

The Gut and Depression.

Depression is widely attributed to a drop in serotonin, a neurotransmitter that is responsible for mood. What’s extraordinary is that only 5% of the body’s serotonin is stored in the brain. The other 95% of the body’s serotonin is stored in the gut. 

It’s not surprising then, that the most commonly used antidepressants that work on changing serotonin levels often come with a side of gastrointestinal issues. It’s also not surprising that the gut might play more of a role in depression than we yet realise. Research continues to look down this track for answers.

The Gut and Anxiety.

Researchers have found that young adults who eat more fermented foods (which contain probiotics) have fewer symptoms of social anxiety. As explained by Psychology Professor Matthew Milimire, ‘It is likely that the probiotics in the fermented foods are favourably changing the environment in the gut, and changes in the gut in turn influence social anxiety … the microorganisms in your gut can influence your mind.’

Food and the Comfort Factor.

The need for comfort rarely sees us diving for the celery. Pity. Instead, ‘comfort food’ tends to be high fat, high energy food. 

The relationship between food and mood isn’t all in our heads. Yes comfort food tastes delicious, smells delicious and might remind us of times we felt happy and secure, but there’s so much more to it than that, as a team of  Belgian researchers have shown.

The researchers delivered nutrients to the stomachs of participants via a nasogastric tube, with the intention of taking away the smells, tastes and memories that are typically associated with comfort food. The participants were given either ordinary saline solution or an infusion of fatty acids.  Without knowing what they were receiving through the tube, those who received the fatty acids reported half the levels of sadness and hunger compared to those who received the saline. This also showed up in brain scans. Very quickly after fatty acids hit the stomach, scans showed greater activity in the part of the brain that moderates emotions.

Stress and Food

Early research found that stressed-out mice would opt for a higher-fat food (peanut butter) over regular chow. Not surprisingly, they put on more weight than their less stressed friends. In times of stress, the gut amps up the production of ghrelin, a hormone that signals hunger to the brain. Research in humans has found similar results. In a recent study, couples were found to have significantly higher amounts of the appetite-triggering hormone following an argument. The researchers stop short of suggesting that unhealthy relationships cause poor food choices, but they acknowledge that the correlation is a strong one.

There seems to be little doubt that one of the ways stress influences behaviour is via the gut, specifically on the production of ghrelin, which sends messages to the brain around appetite and food choices.

Could gut bacteria be behind this?

Mayer points out that the last 50 years has seen a dramatic rise in autism, multiple sclerosis, Parkinsons and obesity. All of these have altered gut bacteria and brain-gut interactions. At the same time, throughout the last fifty years, we have dramatically changed the way our food is produced and processed, and the way we use antibiotics. Has the way we’re doing things lead to the dramatic increases? At this stage, it’s only speculation, but it’s an area of research that is gaining traction.

Where to now?

Mental health is not all in our head. Neither is mental illness. Finally, science is giving us real proof of this. There is little doubt that mental and emotional health is influenced by the state of our gut. The research is exciting and is promising to revolutionise treatments for a range of conditions and the way we take care of our mental health.  

The research is constantly evolving, but what we know for sure is the importance of  being attentive to the state of the gut and doing what we can to keep it healthy. It holds our second brain, and quite possibly, one of the vital keys to our mental and emotional well-being.

73 Comments

Noeleen

Oh…. my son has so many problems with ADD and drug usage…THIS would help explain and stop his depression , drug use and self harm. Thank you.

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Suzanne

For years I had many problems associated with my bowels. Usually it was constipation and lack of motility. I saw many gastroenterologists who offered very little advice. As a child I had been on antibiotics constantly, my tonsils were removed at 5 1/2 but still I would vomit, nothing helped. It took until I was in my mid 50’s to find a specialist who did breath testing for lactose and fructose malabsorptions. I tested positive to fructose malabsorption and have been much healthier and happier for the past few years. Knowing why I had suffered for most of my life from anxiety had a huge positive affect on my mental health and outlook. Changing my diet and including the right type of fermented yoghurt has improved my quality of life enormously. My bowels still are a challenge at times but my outlook on life is so much more positive and my emotions are more controlled.

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Dave

Interesting, succinct and informative. This opens up a whole new way for me to look after myself.

Thanks for writing this article in a way that makes it easy to read and understand.

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Karen Young

Generally speaking, fermented foods and foods that contain probiotics and prebiotics are good for gut health and mental health. Here is an article with some examples https://www.heysigmund.com/a-simple-way-to-reduce-social-anxiety/. If you start including fermented foods in your diet, it’s important to do it slowly. The article on the link explains why. A naturopath would be able to help you with a diet that is tailored more for you and which is more targeted for your symptoms.

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Bulbul

I have been having a bad digestive health for years and now as I am changing my diet and adding probiotics I feel my mood shift. Anxiety and depression are surfacing as the bad bacteria is being released… enema can help cleanse the colonic bad bacteria. I always feel better after enema.

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Andrea

I’ve also felt gut problem ,but I couldn’t relate all this with stress……Even I didn’t know earlier that this is happening because of stress…..I’m taking antibiotic for two years….But I can feel that belly pain or gastronomy problem is happening after stress.Your article helped me more clearly to understand about second brain….Keep sharing more articles like these…..thank you.

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Judt

Thanks for this. It’s a great article. So what is the best diet or supplements to take?

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Shiraz

Hi, I first had loose watery stools and stomach gas for about 10 days and then got into depression. This shows that the gut plays a major part in mental illness from my experience. There can be other reasons but for me it is my stomach.

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Samantha

This. This relates so much with the Serotonin Power Diet that I have been on for the last three weeks and have seen significant changes to my health (for the better) than previously. I am so glad to see more and more concrete evidence of how it is that mental illnesses are just a result of chemical imbalances and what that all means.

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Samantha

Best to look it up. High carb low fat diet. It worked well for me to get me out of the funk I was in at the time. That was four months ago. It is worth it to get out of the cycle of fatigue that you may find yourself in when life happens, but long term once your body starts feeling good again, you’ll need to start reducing it back to normal levels again.

Reply
Zorica

How would having a Gastric band effect the emotions/ depression/ anxiety based on your findings??? Please

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Karen - Hey Sigmund

It’s a very good question. I’m not familiar enough with the research around gastric banding to answer it though. A doctor or your specialist would be the best person to talk to about this.

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Karthik

Thanks for this article.

My sister practices an ancient healing art called “VARMAM” … which is being practiced in India by a few. She was telling me that her patients with depression, anxiety, stress and mood swing symptoms … all of them invariably had a very bad stomach condition.

She just administered the touch healing points for the stomach … and they become perfectly alright on the 3rd day. All happy and smiling!

Certainly probiotics is a wonderful food. In India, we take buttermilk regularly in our meals, which helps in overall wellbeing.

God Bless your good work. Your articles are very very nice! My wife keeps reading all of them regularly.

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Karen - Hey Sigmund

Thank you so much, and for sharing parts of your story. There are so many methods of healing that we need to learn more about. I love hearing when these are being practiced successfully.

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Judith

I am so happy to read this. Posted immediately. For so long I’ve been (almost yelling) “It’s not mental – it’s physical!!!” unfortunately to those very hard of hearing. ie, the experts.

Validation is so so so sweet! Thank you

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Karen - Hey Sigmund

You’re so welcome Judith. They are absolutely physical and the research is proving it over and over. I just wish there wasn’t such a lag between the research and mainstream. There are too many things that are being treated with old knowledge, without accounting for the new things that science is discovering. All the best to you.

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For our children, we start building the foundations for adolescence in their earliest years - the relationship we’ll have with them, who they are going to be, how they are going to be. One of the things we’ll want to build is their capacity to know their own minds and be brave enough to use it. This isn’t easy, even for adults, so the more practice we give them, the more they’ll be able to access their strong, brave, beautiful minds when they need to - when we aren’t there.

This means letting them have a say when we can, asking their opinions, and letting them disagree.

When kids and teens argue, they’re communicating. We need to listen, but the need won’t always be obvious. When littles argue because it’s spaghetti for dinner and ‘I hate spaghetti so much’ (even though last week and the 5 years before last week, spaghetti was their favourite), they might be expressing a need for sleep, power and influence, or independence. All are valid. When your teen argues because they want to do something you’ve said no to, the need might be to preserve their felt sense of inclusion with their tribe, or independence from you. Again, all valid. 

Of course, a valid need doesn’t mean it will always be met. Sometimes our needs might need to take priority to theirs, such as our need to keep them safe, or for them to learn that they can still be okay if everything doesn’t go their way, or that sometimes people will have conflicting needs that need to take priority. What’s important is letting them know we hear them and we get it.

It’s going to take time for kids to learn how to argue and express themselves respectfully. In the meantime, the words might be clumsy, loud, angry. This is when we need to hold on to ourselves, meet them where they are, let them know we hear them, and step into our leadership presence. We might give them what they need because it makes sense and because there isn’t enough reason not to. Sometimes, after giving them space to be heard we’ll need to stand our ground. Other times we might solve the problem collaboratively: This is what you want. This is what I want. Let’s talk about how we can we both get what we need.♥️
Anxiety will always tilt our focus to the risks, often at the expense of the very real rewards. It does this to keep us safe. We’re more likely to run into trouble if we miss the potential risks than if we miss the potential gains. 

This means that anxiety will swell just as much in reaction to a real life-threat, as it will to the things that might cause heartache (feels awful, but not life-threatening), but which will more likely come with great rewards. Wholehearted living means actively shifting our awareness to what we have to gain by taking a safe risk. 

Sometimes staying safe will be the exactly right thing to do, but sometimes we need to fight for that important or meaningful thing by hushing the noise of anxiety and moving bravely forward. 

When children or teens are on the edge of brave, but anxiety is pushing them back, ask, ‘But what would it be like if you could?’ ♥️

#parenting #parent #mindfulparenting #childanxiety #positiveparenting #heywarrior #heyawesome
Except I don’t do hungry me or tired me or intolerant me, as, you know … intolerably. Most of the time. Sometimes.
Growth doesn’t always announce itself in ways that feel safe or invited. Often, it can leave us exhausted and confused and with dirt in our pores from the fury of the battle. It is this way for all of us, our children too. 

The truth of it all is that we are all born with a profound and immense capacity to rise through challenges, changes and heartache. There is something else we are born with too, and it is the capacity to add softness, strength, and safety for each other when the movement towards growth feels too big. Not always by finding the answer, but by being it - just by being - safe, warm, vulnerable, real. As it turns out, sometimes, this is the richest source of growth for all of us.
When the world feel sunsettled, the ripple can reach the hearts, minds and spirits of kids and teens whether or not they are directly affected. As the important adult in the life of any child or teen, you have a profound capacity to give them what they need to steady their world again.

When their fears are really big, such as the death of a parent, being alone in the world, being separated from people they love, children might put this into something else. 

This can also happen because they can’t always articulate the fear. Emotional ‘experiences’ don’t lay in the brain as words, they lay down as images and sensory experiences. This is why smells and sounds can trigger anxiety, even if they aren’t connected to a scary experience. The ‘experiences’ also don’t need to be theirs. Hearing ‘about’ is enough.

The content of the fear might seem irrational but the feeling will be valid. Think of it as the feeling being the part that needs you. Their anxiety, sadness, anger (which happens to hold down other more vulnerable emotions) needs to be seen, held, contained and soothed, so they can feel safe again - and you have so much power to make that happen. 

‘I can see how worried you are. There are some big things happening in the world at the moment, but my darling, you are safe. I promise. You are so safe.’ 

If they have been through something big, the truth is that they have been through something frightening AND they are safe, ‘We’re going through some big things and it can be confusing and scary. We’ll get through this. It’s okay to feel scared or sad or angry. Whatever you feel is okay, and I’m here and I love you and we are safe. We can get through anything together.’

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