It is becoming increasingly accepted that there is a solid connection between gut health and mental health. While this connection may be unexpected, physiological and neurological links have been found to connect our gut and brain.
So, how does anxiety connect with gut health? Let’s take a deeper look.
Anxiety Is Becoming More Common
Anxiety disorders are becoming an increasingly common condition in the United States.
In 2008, anxiety affected roughly five percent of Americans over 18. By 2018, the number had increased to about seven percent.
In young adults specifically (aged 18 to 25), roughly eight percent experienced anxiety in 2008. The number would nearly double to 15 percent by 2018.
The recent global pandemic and ensuing economic instability may have increased the prevalence of anxiety and depression by 25% worldwide. These numbers will likely decrease as society moves farther away from the COVID-19 pandemic. However, there are likely to be several long-lasting consequences for mental health.
Women, in particular, are much more susceptible to developing anxiety disorders than men. The prevalence of anxiety in women is roughly 23% and only 14% for men. It’s unclear what causes the disproportion, but leading theories include differences in brain chemistry, hormonal fluctuations, and societal pressures.
The higher prevalence of anxiety in women might explain why they’re also disproportionately affected by Alzheimer's Disease. More than six million Americans live with Alzheimer's, and nearly two-thirds are women. The odds of a woman developing Alzheimer’s after age 65 are roughly one in five.
Anxiety is present in roughly 40% of patients diagnosed with Alzheimer's disease. Worsening anxiety is often a precursor to Alzheimer's and could be an early indicator of the neurodegenerative disease.
Research has yet to provide a definitive link between the two conditions. Fortunately, there are several charities out there that are determined to learn more. The Women’s Alzheimer's Movement is a leading example and partners with multiple companies to help fund research.
In the meantime, we’ll have to rely on what’s been discovered with current research. One promising area of study is that gut health appears to impact brain health.
The microbiome in your gut can affect inflammation in your brain and have a positive effect on brain health. Employing “nutritional interventions” might effectively reduce the prevalence of anxiety and other mental disorders.
What Is the Microbiome?
The microbiome consists of roughly 40 trillion microorganisms living in your gastrointestinal tract. These healthy gut organisms include bacteria, fungi, parasites, and viruses. While that information might sound alarming, you need all these organisms to stay healthy.
The microbiome is a supporting organ as it’s involved with several essential bodily functions — the components that make up the microbiome help with digestion, stimulate the immune system, destroy harmful gut bacteria, and synthesize essential vitamins and amino acids.
The particular network of microorganisms will differ for each person, and DNA largely determines this. Research has found that roughly 97% of microbiome traits are genetically inherited.
In other words, it’s practically guaranteed that you’ll experience gastrointestinal issues, disorders, or conditions if your parents did.
How Does the Microbiome Affect the Brain?
The brain-gut connection is a bit complicated, to say the least. Many factors are involved that we know of, and even more that we don’t.
However, it can be explained a little easier by boiling it down to three distinct components:
- The amygdala is located in the brain and is the integrative center for your emotions. The amygdala largely determines how you respond to stimuli — this is where your stress response gets activated. If the amygdala is overactive, then it could result in experiencing chronic anxiety symptoms, depressive symptoms, and overall poor mental well-being.
- Gut peptides such as glucagon-like peptide 1 (GLP-1), pancreatic polypeptides (PP), and neuropeptide Y (NPY) are chemical messengers produced by the microbiome. These peptides signal the amygdala, which elicits an emotional response. An imbalance of gut peptides can result in negative emotions such as anxiety, stress, and depression.
- Short-chain fatty acids (SCFAs) are produced by the microbiome and can be in certain foods. SCFAs play a crucial role in maintaining the integrity of the intestinal barrier and mucus production. However, they’re also extremely important for balancing, regulating, and controlling the secretion of gut peptides.
To summarize, the SCFAs produced in the gut can help to regulate the gut peptides that influence the emotional center of your brain.
Theoretically, helping to balance gut peptides can help limit the amygdala's response and reduce the frequency of experiencing stress and anxiety, and may relieve symptoms of mental illness.
What Is Neurological Inflammation?
Inflammation, at a very high-level, is the body’s response to an irritant. Inflammatory chemicals help to attack perceived threats and also help to repair damaged tissues.
The problem with inflammation is that chronic and excessive levels can result in tremendous damage to otherwise healthy cells, tissues, and organs.
Neurological inflammation is an inflammatory response limited to the brain and spinal cord. Measuring cerebral spinal fluid can help determine neurological inflammation based on the number of cytokines, chemokines, reactive oxygen species, and other proinflammatory proteins.
There is evidence for a very clear relationship between neurological inflammation and psychiatric disorders.
It’s believed that excessive levels of inflammation can result in neurotransmitter imbalance. Neurotransmitters such as dopamine, serotonin, acetylcholine, glutamate, and GABA are essential to proper brain function and balanced mental health.
Inflammation in the brain can hinder the production, release, and effectiveness of these neurotransmitters.
How Can the Microbiome Affect Neurological Inflammation?
As mentioned earlier, the microbiome is crucial in stimulating the immune system. Inflammation is how the immune system responds to perceived threats. Experiencing inflammation in the digestive system stimulates the release of inflammatory immune cells.
These cells can eventually find their way into the central nervous system, traveling to the brain and aggravating neuroinflammation. Inflammation in the digestive tract largely results from the immune system responding to triggers that it experiences.
The microbiome releases inflammation whenever it perceives food components as harmful toxins, viruses, or bacteria. The exact triggers will vary depending on the individual microbiome composition. However, there are a few triggers that are universal amongst humans.
Which Foods Can Contribute to Anxiety?
It’s important to note that there are a ton of variables that determine someone’s prevalence of anxiety. There is no way to state with certainty that eating certain foods will result in experiencing anxiety or developing a mental disorder.
However, a few foods can hurt the microbiome and increase inflammation in the gut. The odds of experiencing anxiety will increase as these two factors are a major precursor for the condition.
The following foods appear to have the most significant link to anxiety:
Sugar (in some form or another) can be found in a majority of foods you eat. Generally, experts recommend choosing more natural (“good”) sugar and limiting the amount of added (“refined”) sugar. Refined sugar, in particular, can be especially detrimental to brain health.
Refined sugars (such as high fructose corn syrup) can cause lipogenesis (i.e. creation of fats) in the body, particularly visceral fat. This type of fat wraps around the organs in the body, helping to protect and insulate them. The problem is that too much visceral fat can produce various adipokines, which are highly inflammatory.
Refined sugars can also attach to various molecules in the body and create advanced glycation end products (AGEs) in the brain, which can induce inflammatory responses in high levels, resulting in neurological inflammation. The vascular system is especially affected by AGEs, which can mean limited blood and oxygen supply to the brain.
Saturated fat has a similar effect on the body as refined sugars. Fats contain about nine calories per gram, which is more than double the ratio of carbohydrates and proteins.
Eating an excessive amount of calories can result in weight gain and the lipogenesis of visceral fat. As mentioned above, increased visceral fat can result in elevated inflammation levels via adipokines.
Additionally, saturated fat can increase your body’s circulating amount of low-density lipoprotein (LDL), which is often referred to as “bad cholesterol.” Elevated LDL levels can cause various issues with cardiovascular health such as clogged arteries and higher risk for heart disease.
Artificial sweeteners have been used to replace refined sugars since the 1950s. The goal was to create a substitute for sugar with the same taste and no calories. While artificial sweeteners can provide this calorie-free sweetness, they can also come with a variety of negative health effects.
Artificial sweeteners, such as aspartame, can affect systemic metabolism, abdominal obesity, glucose tolerance, insulin resistance, and blood pressure. These issues are not only key contributors to increased inflammation, but diabetes and cardiovascular disease as well.
Another major issue is that consuming artificial sweeteners can increase the amount of phenylalanine and aspartic acid in the brain. These chemicals can prevent the production and release of essential neurotransmitters such as dopamine, serotonin, and norepinephrine.
Noting a point made earlier: Neurotransmitter imbalance is a leading contributor if not the leading contributor to anxiety and other mental health problems.
Processed Vegetable Oil
Processed vegetable oil such as corn oil, canola oil, and soybean oil are loaded with omega-6 fatty acids. It can be good to eat some foods containing omega-6 fatty acids because fatty acids are essential to several bodily and brain functions.
However, eating too many omega-6 fatty acids can trigger the body to produce pro-inflammatory chemicals.
Most foods containing omega-6 fatty acids also include antioxidants that can help limit the body's inflammatory response. The problem with processed vegetable oil is that these antioxidants are stripped during extraction.
Left unchecked, excessive levels of omega-6 fatty acids can cause severe oxidative stress in cells and tissues throughout the body and brain.
Gluten is a protein primarily found in wheat, barley, and rye. The main issue with gluten is that it can contribute to a condition known as “leaky gut syndrome.” The zonulin proteins found in gluten can increase the permeability of the gut.
When this occurs, the immunity-stimulating compounds located in the gut leak out into the bloodstream. The compounds travel throughout the body and brain, triggering an inflammatory response.
Zonulin proteins are especially an issue for individuals with Celiac disease, irritable bowel syndrome, and other gastrointestinal conditions. However, elevated levels of zonulin proteins can reduce gut permeability for anyone. Blood tests can measure the number of zonulin proteins in the blood and help determine whether a dietary change can be helpful.
Can Changing Your Diet Help With Anxiety?
Trying to avoid some of the food compounds mentioned above can be an excellent start to reducing anxiety symptoms. In addition, eating more foods that promote positive brain health can also be beneficial.
Again, no scientific research suggests that eating these foods will eliminate anxiety, but their overall benefits may be able to help improve symptoms, especially in combination with other treatment methods like cognitive-behavioral therapy (CBT) as well as eliminating the anxiety-inducing foods above!
Your gut microbiome needs a healthy balance of good bacteria to do its job. An imbalance in these gut microbes (called dysbiosis) can trigger an immune response and digestive upset.
While you may feel an imbalance in your stress levels, you may also notice physical signs of gut imbalance, like constipation and bloating. These chronic symptoms can also indicate bowel diseases like irritable bowel syndrome (IBS).
Many people take probiotic supplements to help rebalance temporary imbalances in gut bacteria. These supplements often contain trillions of live bacteria that can help balance the gut microbiome and improve overall wellness. While probiotic supplements include many strains of bacteria, one of the most popular is the Lactobacillus strain.
If supplements aren’t your thing, you can also incorporate probiotic foods into your diet. These include fermented foods like sauerkraut, kombucha, kefir, yogurt, and sourdough bread.
Prebiotics are also good foods to add to your diet. Prebiotics are foods that can help nourish your good gut bacteria. Some examples of prebiotics include legumes and asparagus.
Curcumin is in the turmeric plant, commonly used to create curry powder. Studies have shown that curcumin can improve the microbiome ecosystem, inhibit inflammation precursors, and regulate the levels of essential neurotransmitters. These beneficial properties have led to curcumin being tested as a potential treatment for Alzheimer’s.
The difficulty with curcumin is that the body needs a tremendous amount to illustrate these benefits. Curcuminoids are fat soluble, and it can be difficult to consume the number of fats needed to absorb curcumin safely. Nano-curcumin and Bioperine were used in the studies listed above to increase the availability of curcumin in the body.
Curcumin does also provide more benefits that make it a worthwhile addition to diets. Curcumin can help increase the amount of alpha-linolenic acid (ALA) converted to docosahexaenoic acid (DHA). Humans struggle to maintain a sufficient conversion ratio, but curcumin can help increase the enzyme required.
Most people that follow a keto diet are doing so to burn excess fat and lose weight. While this is one possible health benefit of a keto diet, it’s not the only one. Keto diets can also benefit your brain, resulting in an elevated number of ketones.
The liver produces ketones as an alternative fuel source for the brain. Normally, carbohydrates break down into glucose for fuel. When limiting carbs via a keto diet, the body enters a state of ketogenesis where fats are used to create ketones.
Remember that fat has more than twice the number of calories as carbs. Calories are a measurement of energy, meaning ketones are a much more efficient energy source than glucose. Ketones can also help improve the gut microbiome and reduce inflammation and oxidative stress.
For these reasons, the keto diet has long been used as a possible treatment for neurodegenerative conditions such as epilepsy, Parkinson’s, and Alzheimer's. It’s currently being studied as a potential treatment for various other mental disorders, including anxiety.
The Bottom Line: Taking Care of Your Gut Health May Be Able To Help With Anxiety Symptoms
It’s becoming increasingly clear that gut health and anxiety are closely related. Taking care of one can help to alleviate issues experienced with the other.
If you’re experiencing chronic anxiety, it’s possible that making a few changes to your diet can help. Replacing some of the negative foods listed above with healthier alternatives can go a long way toward improving your mental health.
There’s still a lot that remains a mystery about what causes neurological disorders such as anxiety and Alzheimer's. Fortunately, there are people out there that are determined to learn as much as possible about them.
MOSH's mission is to create a conversation about brain health with food, education, and research — a portion of all our proceeds will be donated to the Women’s Alzheimer's Movement, which you can learn more about here.
Looking for more good reads on brain and body wellness? Explore the rest of our blog here!
Limbic System: Amygdala (Section 4, Chapter 6) Neuroscience Online: An Electronic Textbook for the Neurosciences | Department of Neurobiology and Anatomy - The University of Texas Medical School at Houston