Lately, we’ve been hearing a lot about probiotics in the media. Supplements are filling up pharmacy shelves, yogurt commercials can be found playing on repeat, and fermented foods like sauerkraut are finally being used in more places than atop the occasional hotdog or Rueben sandwich.
With a surge of microbiome-related research emerging in recent years, it has become common knowledge that the bacteria colonizing the gastrointestinal tract have a major impact on physical health. Now, substantial evidence is showing that the upkeep of a healthy microbial environment in the intestines is also hugely important for brain development, mood and cognition. Prebiotics are also key here.
In other words- it is entirely possible and probable that probiotics improve your brain.
The Gut-Brain Connection
In the body, single cell organisms– primarily in the form of bacteria– outnumber human cells ten to one. Over 100 trillion of these teeming microbes take up residence in the gastrointestinal (GI) tract, where they are hard at work tearing apart food to extract useful vitamins and minerals, and taking a valiant stand against dangerous pathogenic invaders when needed.
Yet in addition to their local roles in optimizing the digestive and immune systems, these little organisms have something much bigger going on: the microbes in the gut partner with the nervous system to send messages throughout the body and to the brain.
The digestive tract has deep, physiological connections to the central nervous system. After all, information relating to hunger and satiety must be exchanged between the two in order for us to survive.
The gut even has its very own set of nerve cells, or neurons, embedded in the intestinal walls. These millions of GI neurons make up a highly integrated neural network called the enteric nervous system. With as many neurons as the spinal cord, the enteric nervous system is so sophisticated and complex that some have ventured to call it the “second brain.”
The vagus nerve, nicknamed the “wandering nerve” serves as the major conduit between the enteric and central nervous systems. As the longest cranial nerve, it extends from the brain stem right down to the abdomen, allowing signals to pass freely between these locations.
Interestingly, about 90% of the fibers in this spindly nerve carry signals upwards from the bowels toward the head, and not the other way around. This orientation allows the microbes in the gut to send powerful messages that can actually steer the high-level emotional processing that occurs in the brain. (1)
Roles of Probiotic Bacteria
The idea that the microorganisms in our bellies could influence how we think and what we feel is a shocking one. To understand this gut-brain connection further, let’s look at some of the main pathways through which microbes in the gut impact the nervous system.
- Promote growth and development of neurons. Compounds produced by the microorganisms in the gut stimulate the release of neural growth factors, the proteins that encourage the formation and survival of nervous system cells. Research is now suggesting that even before birth, maternal-fetal transmission of bacteria occurs through the amniotic fluid and umbilical cord blood, stimulating early nervous tissue development. After birth, microbes from the outside environment (including those from breastmilk, foods, contact with siblings and pets, etc.) continue to enter the body and shape the nervous system throughout late childhood and even beyond. (2,3)
- Stimulate memory and learning. Certain strains of gut bacteria produce chemicals that stimulate a sympathetic, or “active” response in specific parts of the brain. Often this occurs in regions involved in decision-making, planning, and attention such as the frontal cortex and hippocampus. Bacterial metabolites are thus very important for jump starting the biochemical processes involved in memory and learning. (4)
- Guide changes in mood. Select microorganisms help to produce mood-regulating neurotransmitters like serotonin, GABA and melatonin. Over 30 different bacterially-derived neurotransmitters work locally in the tissues of the gastrointestinal tract, and also relay signals to the central nervous system. It has been suggested that almost 95% of the body’s serotonin is produced in the gut. (5)
- Shift digestive patterns. Metabolites from bacteria stimulate sensory nerves in the intestines to change gut motility patterns. Feedback from these motor changes is then relayed to the brain, where a response is elicited. Pain and anxiety are two of the most common reactions. This cross-talk is one of the reasons why psychiatric disorders are often accompanied by chronic digestive problems and vice versa. (6)
- Influence the expression of genes. It was once believed that genes were destiny. However, it is now known that many lifestyle factors have a profound influence on the ways in which genes are expressed. The study of epigenetics has revealed that microorganisms play a large part in this. Bacteria in the gut hold the potential to change patterns of DNA methylation, thus switching certain genes on or off. (7)
Can Probiotics Improve Your Brain?
These findings have raised many intriguing questions. Would altering the microbiome change predispositions to psychiatric disease?
Could probiotics be used to treat conditions such as anxiety and depression?
The short answer is a loud and enthusiastic yes, although an abundance of research will be needed before targeted clinical strategies are brought to the mainstream.
In the meantime, there are many steps that can be taken independently to fortify the gut microbiome and heal the brain.
A nutrient-dense diet filled with fermented foods is a powerful place to start, especially when Probiotics is added in.
Opting for gentle personal care products that won’t eradicate beneficial bacteria is another often-overlooked step, as is drinking pure, chemical-free water.
For those seeking more specific treatments, connecting with a functional medicine clinician or naturopathic doctor who can help develop an individualized plan is important and will be immensely helpful as well.
Do you take probiotics? Have you noticed a difference in mental clarity when taking?
Discussion (17 Comments)
It is amazing to think that we are 90% symbionts and 10% human cells. If that ratio represents the ratio over what controls our bodies and minds – then it is even more mind-blowing.
I just finished an interview with Prof Lowry of Univ of Col, where he discussed some studies that correlate higher levels of IL-6 (interleukin 6 – a marker of inflammation) at a young age with depression and psychosis symptoms years later in early adult life ( http://www.healinghacker.com/talking-microbiota-everything-from-allergies-to-depression/ ). We also discussed other environmental saprophytes (like m vaccae found in the orange slime of a hippo-feces infested lake in Kenya) that modulate the immune system towards the anti-inflammatory processes and help ease everything from asthma to depression.
I would add that probiotics are super – as are fermented foods. They are, in my opinion, key. However, and I say this from our experiences, I’ve found that using probiotics for specific issues – say something like crohns or allergies – requires intensive research because results are super strain specific. Meaning, it’s not just l. acidophilus – it’s l. acidophilus xyz123. Different strains of species have different impacts on the immune system. If you’re just looking to add to existing health, I don’t think you need to be as diligent in your strain research. But if you want to shift something existing, you need to find the research behind specific strains and then be willing to do self-experimentation.
This is my experience and opinion. I’m not a doc or scientist – just an obsessed mom looking for answers and healing.
can kiefer water be good for my baby? how can i give him some? or should i say how much?
Love this article! Complete and concise!
About this time last year I accidently found kefir which is a great source of probiotics. I struggled with sever hand dermatitis (eczema) since I had my first daughter in 2008 – to the point I literally couldn’t use my hands at all – and after starting to drink kefir regularly, my eczema has completely healed up. I just use the Lifeway brand and add it to our smoothies, and we try to have the smoothies about 3 times a week. Also, my oldest daughter started her first year of school this past school year, and her doctor warned me that since I stayed home with her and she never went to a daycare/preschool/babysitter, she would probably get sick a lot. I am happy to say that she only missed one day from being sick (which she actually was fine and should have went that day – haha!). She was directly exposed to Type A influenza at least 3 times that I know of, not to mention stomach bugs, and multiple viruses, yet I believe she missed the least amount of days of anyone in her class. I give the credit to regularly consuming the kefir.
I’m kinda new to the “Wellness Mama” world but being naturally curious I watched an interview with you on the Randy & Christa show and it really struck home with me how I too had a c-section and my son was diagnosed with GERD then later in life diagnosed with Leaky Gut Syndrome. (I contacted you earlier about that- thanks for the bone broth suggestion!) I am about to have another c-section in July and I will be sure to up my probiotic intake and super charge my diet so hopefully it doesn’t happen with this lil guy too. Do you suggest a specific probiotic , the one I have is 3 billion I believe…..
Katie - Wellness Mama
I used Bio Kult and also gave to baby… I’d also highly encourage you to watch Micrbirth, a documentary, as it has a great protocol for culturing your baby to your healthy gut bacteria if you have a c-section. Best wishes for a wonderful birth and congrats on your pregnancy.
Katie, thank you so very much for this article!! My daughter was diagnosed ASD Level 1 last year. We saw intense issues of hyperactivity and the inability to focus or impulse control delays. It was frustrating because we were constantly trying to point at our own faces to get her to look at us so she could process what we were saying. We started ABA therapy as soon as we had the diagnosis, but change was slow. I ended up reading articles about the use of probiotics in Europe as a means to help children focus not only with ADHD, but those on the Autism Spectrum as well. So instead of giving them these intense prescriptions that can harm the developing neural pathways in the brain for hyperactivity and stunt growth, the probiotics don’t do that. We give her culturelle for kids in the chewable tablet (it contains xylitol). It has not only made her bowels more regular, but she is much calmer. The calmness is more in the sense to take a moment and process information. She still runs around, screams, plays, and can still produce a good amount of tears, but her ability to control impulsive behavior (especially with guidance) has improved greatly. Another improved issue is her ability to maintain eye contact. We had very little of that and had to introduce a lot more signs to get her to look at us and try to understand what we were saying. We noticed such a direct effect when her insurance needed a new prior-auth this year for the probiotics. She didn’t have her doses for a little over a week and ABA could not get her to sit still. We lost a therapist because she just couldn’t handle my daughter. After the first day back on the probiotics, we saw significant improvement which progressed back to where we were completely within a few days time. I know the probiotic we use isn’t as high quality, but if this is working for us, I can only imagine what using a higher quality probiotic could do for someone. I’m trying to find someone in my area who can pass along a scoby at some point and teach me how to make kombucha. I would love to give that a try for my daughter and see how effective it works for her!
Hi Katie, this is a interesting post. What type of supplements do you take on a daily basis. I read your blog on a regular and just confused on how many different supplements should be taken on a daily basis. Currently I am only doing sole water in the morning and fish oil after breakfast.
Katie - Wellness Mama
Good question …here is part of my daily routine, though it varies by season quite a bit https://wellnessmama.com/55187/morning-routine/ I usually take a soil based probiotic before bed
Katie, This was THE. MOST. EXCITING. POST. I have read from you to date. I’ve wondered what is known about what turns genes on and off, but have not taken time to really look into that *successfully*. In the meantime, I’ve been gearing up to try to organize my immune system yet again (several recluse bites and various tick bites later, and all that after liver dysfunction for some#of years, and now I’m much older to boot…. BUT…. it’s time to try again…..). I’ve not put enough emphasis on probiotics, in great part because the ones I had tried from time to time were (apparently) not high enough quality for my needs and/or etc. — I have finally been on a better probiotic (along with various other changes which I’m slowly turning into habits), but at this point, I might switch to whatever probiotic you recommend. This really is absolutely and utterly exciting news! Thank you, thank you, thank you, thank you, thank you!!!!!
My son’s stomach is havoc.
he has methylation problems
has gotten lactic acidosis
how on earth can help him I’ve tried everything
Is prescript-Assist the only probiotic you take? What is it about this particular brand that stands out to you as opposed to the countless others out there?
Katie - Wellness Mama
I just noticed the most difference from it in my digestion and how I felt, but it comes from soil based strains, which some research shows may survive longer in the digestive system and do more good