The correlation between the gut and brain; also known as the gut-brain axis, is becoming more widely talked about and understood. This is a broad-term used to describe the psychosomatic factors involved in digestive processes. In other words, it refers to the effects our psyche (thoughts and emotions) have on our digestive function.
The basic concept to grasp here is that there is an interrelated network between the brain’s signals and the functioning of our digestive system. This is a two-way street, where psychological stress can inhibit good digestion, but also, where biological stress in the gut can negatively affect our mood.
Due to this understanding, common anti-depressants (serotonin reuptake inhibitors), 5-HTP, and L-tryptophan have been commonly prescribed to those with digestive complaints like IBS, constipation and diarrhea. However, due to the nature of serotonin, this isn’t necessarily a helpful idea.
Serotonin is usually something people think they want to get more of; especially if they are “depressed”. People are often told that their depression is the result of a chemical imbalance, where they do not produce enough serotonin. However, this is a simple misunderstanding in cellular physiology.
The fact of the matter is, serotonin is a stress chemical and inhibiting gut serotonin can actually help to treat many diseases including IBS, digestive issues, weight problems, and mental and mood disorders.
Why is it promoted then? Well, for the simple fact that increasing serotonin can increase gut motility, being a great help to those with chronic constipation. But this is simple due to the stimulating nature of serotonin, which isn’t necessarily a good thing in the long run. It is important to understand that simply defecating regularly is not a key cornerstone of good digestive health – there are other parameters to consider.
One of the first things to understand is that the activity of serotonin doesn’t necessarily have an “anti-depressant” effect. While newer anti-depressants increase the action of serotonin, this is not what causes their proclaimed antidepressant activity. The fact is, different antidepressants do different things to serotonin, some increase, decrease, or don't affect serotonin at all. So, the theory of depression being based on “neurotransmitter” or “receptor” imbalance is nothing more than a belief.
To begin to understand serotonin, it’s necessary to look at the broad view of human biology. One thing biologist know about serotonin is that it has interrelated functions with estrogen, which might explain why women are more likely to suffer from depression than men are. Both serotonin and histamine are increased by estrogen, which then have estrogen-mimicking effects.
While serotonin may be involved in mood disorders, it is also involved with a number of other problems. For example, elevated serotonin levels are involved in a variety of energy disorders, related to metabolic function, mitochondrial respiration and thyroid function, such as liver disease, Alzheimer’s disease, and others. This is because serotonin inhibits the energetic ability of these organs.
The main thing to know about serotonin is that it is an excito-toxin and when chronically elevated, can lead to the death of nerve cells and limits cellular energy production. It does so by activating glycolysis, which forms lactic acid. And excess lactic acid is known to decrease energy production by interfering with mitochondrial respiration.
SIBO, Serotonin & Anti-depressants
Looking to the bacteria in the gut to regulate serotonin, one of the metabolic byproducts of different gut microbes is gut serotonin production. If you didn’t know, up to 90% of the neurotransmitters are produced within the gut by microbes. And as we have learned, keeping serotonin in check is actually a key goal for proper energy production, thyroid function, and metabolism.
Elevated levels of this peripheral serotonin have been linked to diseases such as irritable bowel syndrome and other metabolic issues. Which is why there are so many reports of people who take anti-depressants who develop IBS and digestive issues.
Given that the gut microbes product 90% of serotonin, one of the key underlying reasons for elevated serotonin is an overgrowth of bacteria in the gut, namely SIBO (small bacterial overgrowth).
According to studies, mice with normal small intestinal bacterial (keep in mind the small intestine is more or less sterile when healthy), produced approximately 60 percent less serotonin than mice with abnormal, or elevated bacterial colonies. When the “bug-free” mice were colonized a greater number of gut microbes, the serotonin levels went back up. This shows us that serotonin levels can be put in check, and are strongly influenced by the bacteria in the gut.
If this weren’t sufficient reason for dumping conventional anti-depressant medication, consider the following additional side effects:
·Weight Gain: Weight gain is frequently reported from those taking standard anti-depressants (SSRIs) over the long-term. Various uncontrolled studies have reported mean weight gains of 15 lb. (6.75 kg) after taking common anti-depressants after 6 to 12 months of therapy.
·Sleep Problems: It’s common for normal sleep patterns to be disrupted when taking anti-depressants. Studies find that people taking SSRIs have reduced slow-wave sleep, and wake up in the middle of the night more often. SSRIs interfere with sleep architecture, which complicates total sleep time, and sleep efficiency.
·Sexual Dysfunction: The interference in sexual functioning caused by SSRIs is complicated, but involves nitric oxide. The effect appears to be attributable to stimulation of postsynaptic 5-HT2 receptors in the spinal cord. This manifests as decreased libido, male impotence, delayed ejaculation, or anorgasmia. While these are common characteristics of depression itself (an energy problem) they are also well-known negative side-effects of antidepressant medications.
Conclusion: Balancing the Gut
At this point, we have two key pieces of data:
·Anti-depressants that increase the activity of serotonin are not only harmful to overall health, but also have minimal success at improving depression and can attribute to digestive problems.
·Elevated serotonin levels decrease the functioning of the metabolism and can actually attribute to depression by down regulating the thyroid.
Given the nature of the gut-brain axis, if you are someone who is experiencing digestive issues, you likely are experiencing mental and mood imbalances. These are interrelated and are therefore best approached from both ends. The more germ free you keep your gut, the lower your peripheral serotonin levels will be, the higher your metabolism will be and the healthier you will be.
Looking at some things you can do to start improving both of these conditions, my advice would be to first:
1. Get off any anti-depressants if you are on them (consult with your medical doctor BEFORE doing so). Instead, go for a daily walk in nature, start expressing your thoughts and emotions, exercise moderately, find a meaningful hobby to give you external problems to deal with rather than your mental ones.
2. Get a handle on potential SIBO. Simple things like taking activated charcoal + consuming raw carrots can be used for handling SIBO since they all inhibit the growth of endotoxins (pathogenic gut bacteria.)
Ultimately, a shift from standard treatment of depression and digestive issues with the use of medications would be best. These are systemic problems that require a systemic, multi-factorial approach that handles a person across all therapeutic areas, including their mental and emotional well-being, diet, physical activity, sleep, and other lifestyle factors.
In my comprehensive online course Perfect Digestion, I cover these areas and more in detail. Be sure to check out the course page to learn more!
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