By Dr. Mercola
In our never-ending quest for happiness, it sometimes doesn't occur to us that what we're searching for may be right inside our own bodies. Now, a new study shows that the answer to your search for well-being may very well hinge on having the right type of bacteria in your gut.
Many fail to realize that your gut is literally your second brain, and can significantly influence your mind, mood, and behavior.
But mounting evidence indicates that ignoring your gut may have far-reaching psychological consequences, and it's becoming increasingly clear that nourishing your gut flora through proper diet, from cradle to grave, is extremely important for proper brain function, and that includes psychological well-being and mood control.
This "mysterious" connection becomes easier to grasp when you understand that your brain and your gut are actually biologically identical, as they're created out of the same type of tissue.
During fetal development, one part turns into your central nervous system while the other develops into your enteric nervous system.
These two systems are connected via the vagus nerve, the tenth cranial nerve that runs from your brain stem down to your abdomen. The featured research, published in the August 29 issue of Proceedings of the National Academy of Sciences, confirms that the vagus nerve is indeed the primary route your gut bacteria use to transmit information to your brain.
Your Gut Bacteria Dictate Your Mood and Mental Health
This year, we've seen some fascinating research emerge on the connection between gut flora and mental health. While earlier studies have suggested that the mix of bacteria in your intestines have the ability to influence your mood and subsequent behavior in various ways, the featured research investigated how these changes actually come about. For the first time, researchers have demonstrated that probiotics have a direct effect on brain chemistry under normal conditions.
Most of the evidence indicating that gut bacteria affects your central nervous system (CNS) has been indirect. This latest study gives us a better understanding of the mechanics of this influence, and further strengthen the idea that what happens in your gut does NOT stay in your gut.
The authors explain:
"GABA is the main CNS inhibitory neurotransmitter and is significantly involved in regulating many physiological and psychological processes. Alterations in central GABA receptor expression are implicated in the pathogenesis of anxiety and depression, which are highly comorbid with functional bowel disorders.
In this work, we show that chronic treatment with L. rhamnosus induced region-dependent alterations in GABA(B1b) mRNA in the brain with increases in cortical regions (cingulate and prelimbic) and concomitant reductions in expression in the hippocampus, amygdala, and locus coeruleus, in comparison with control-fed mice. In addition, L. rhamnosus (JB-1) reduced GABA(Aα2) mRNA expression in the prefrontal cortex and amygdala, but increased GABA(Aα2) in the hippocampus."
In short, the probiotic Lactobacillus rhamnosus had a marked effect on GABA levels in certain brain regions and lowered the stress-induced hormone corticosterone, resulting in reduced anxiety- and depression-related behavior. When they severed the vagus nerve, GABA receptor levels and the animals' behavior remained unchanged after treatment with L. rhamnosus, confirming that the vagus nerve is most likely the primary pathway of communication between the bacteria in the gut and your brain.
"Together, these findings highlight the important role of bacteria in the bidirectional communication of the gut-brain axis and suggest that certain organisms may prove to be useful therapeutic adjuncts in stress-related disorders such as anxiety and depression," the authors concluded.
Furthermore, did you know that neurotransmitters like serotonin, which are associated with mood, can also be found in your gut? In fact, the greatest concentration of serotonin, which is involved in mood control, depression and aggression, is found in your intestines, not your brain! This lends further credence to the idea that your first step toward balancing your mood would be to nourish your gut flora rather than reaching for a prescription drug.
Psychological Health Begins in the Womb!
Earlier this year, another study published in Neurogastroenterology & Motility found that having sufficient amounts of healthy gut bacteria from birth may be imperative for future psychological health. Mice that lacked gut bacteria exhibited neurochemical changes in their brains, and subsequently behaved differently from normal mice, engaging in what would be referred to as "high-risk behavior."
According to the authors:
"Acquisition of intestinal microbiota in the immediate postnatal period has a defining impact on the development and function of the gastrointestinal, immune, neuroendocrine and metabolic systems. For example, the presence of gut microbiota regulates the set point for hypothalamic-pituitary-adrenal (HPA) axis activity."
This is very important, as many women of reproductive age are deficient in probiotics—a deficiency that transfers to their offspring, and may set the stage for any number of problems!
To get a solid understanding of just HOW important this is, I highly recommend reviewing the information shared by Dr. Natasha Campbell-McBride in this recent interview. She presents a fascinating and elegant description of the foundational conditions that contribute to such disorders as ADHD, learning disabilities and autism, along with a pragmatic approach to help circumvent and stem the autism epidemic—and it all begins with the mother's gut flora.
Dr. Campbell explains:
"The baby acquires its gut flora at the time of birth, when the baby goes through the birth canal of the mother. So whatever lives in mom's birth canal, in mom's vagina, becomes the baby's gut flora. So what lives in mom's vagina? It's a very richly populated area of a woman's body. The vaginal flora comes from the bowel. So if the mother has abnormal gut flora, she will have abnormal flora in her birth canal."
Establishment of normal gut flora in the first 20 days or so of life plays a crucial role in appropriate maturation of your baby's immune system. Hence, babies who develop abnormal gut flora are left with compromised immune systems. And that's where vaccines have the potential to wreak havoc. Vaccinations were originally developed for children with perfectly healthy immune systems, but children with unbalanced gut flora are not fit to be vaccinated according to the standard vaccination protocol.
Her book Gut and Psychology Syndrome is a treasure trove of information that may very well pave the way toward a healthier future for all the new babies coming into this world, as long as people start taking this issue seriously. Every parent should have this book, and share it with their pediatricians...
Gut Flora During Infancy May Permanently Alter Gene Expression
Another animal study also found that gut bacteria may influence mammalian early brain development and behavior, and that the absence or presence of gut microorganisms during infancy permanently alters gene expression. (In a similar way, probiotics have also been found to influence the activity of hundreds of your genes, helping them to express in a positive, disease-fighting manner.)
See Dr. Natasha Campbell-McBride and Me Speak in November
Through gene profiling, they were able to discern that absence of gut bacteria altered genes and signaling pathways involved in learning, memory, and motor control. This suggests that gut bacteria is closely tied to early brain development and subsequent behavior, which is what Dr. Campbell has found as well. These behavioral changes could be reversed as long as the mice were exposed to normal microorganisms early in life. But once the germ-free mice had reached adulthood, colonizing them with bacteria did not influence their behavior.
According to Dr. Rochellys Diaz Heijtz, lead author of the study:
"The data suggests that there is a critical period early in life when gut microorganisms affect the brain and change the behavior in later life."
What Interferes With Healthy Gut Bacteria?
It's important to understand that your gut bacteria are an active and integrated part of your body, and as such are heavily dependent on your diet and vulnerable to your lifestyle. If you consume a lot of processed foods and sweetened drinks, for instance, your gut bacteria are likely going to be severely compromised because processed foods in general will destroy healthy microflora and sugars of all kinds feed bad bacteria and yeast.
Your gut bacteria are also very sensitive to:
- Chlorinated water
- Antibacterial soap
- Agricultural chemicals
Because of these latter items, to which virtually all of us are exposed at least occasionally, it's generally a good idea to "reseed" the good bacteria in your gut by taking a high-quality probiotic supplement or eating fermented foods.
How to Optimize Your Gut Flora
An estimated 80 percent of your immune system is also located in your gut, so reseeding your gut with healthy bacteria is important not just for psychological health but for your overall physical health as well. A robust immune system is your number one defense against ALL disease, from the common cold to cancer. In light of this, here are my recommendations for optimizing your gut bacteria.
- Fermented foods are still the best route to optimal digestive health, as long as you eat the traditionally made, unpasteurized versions. Healthy choices include lassi (an Indian yoghurt drink, traditionally enjoyed before dinner), fermented grass fed organic milk such as kefir, various pickled fermentations of cabbage, turnips, eggplant, cucumbers, onions, squash and carrots, and natto (fermented soy).
If you regularly eat fermented foods such as these that, again, have not been pasteurized (pasteurization kills the naturally occurring probiotics), your healthy gut bacteria will thrive.
- Probiotic supplement. Although I'm not a major proponent of taking many supplements (as I believe the majority of your nutrients need to come from food), probiotics are definitely an exception. I have used many different brands over the past 15 years and there are many good ones out there. I also spent a long time researching and developing my own, called Complete Probiotics, in which I incorporated everything I have learned about this important tool over the years.
If you do not eat fermented foods, taking a high quality probiotic supplement is definitely recommended.