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The Gut-Brain Connection: How Food Sensitivities Can Impact Mental Health


The gut and brain can affect each other’s functions and, in turn, create a positive or negative impact on our emotional health. For example, poor gut health and food sensitivities can make you more vulnerable to developing mental health issues.

Due to the rise in the prevalence of digestive disorders, food sensitivities, and mental health issues, it has become important to learn how to maintain optimal gut health in order to avoid potential complications.

In this article, we will explore the impact of the gut-brain connection on your mental health with a specific focus on food sensitivities. We will also learn how choosing appropriate nutritional and lifestyle interventions based on the concepts of functional medicine can help strengthen the gut-brain axis and improve our emotional wellness.

What is the Gut-Brain Axis?

We all have experienced butterflies in the stomach or a gut-wrenching feeling before an exam. Sometimes, we also feel rumbling and gurgling in the stomach or feel nauseous before important events.

To feel butterflies in the stomach or have a gut-wrenching feeling are not just verbal expressions but actual sensations that we feel due to the impact of our neurotransmitters on our gut functions.

These symptoms tell us how strong the gut-brain axis is and how the brain can affect the gut and vice versa.

The gut-brain axis basically refers to the link between the gut and the brain, wherein both these vital organs affect each other. [1]

The functions of the gut, including the movement of food, hunger pangs, and digestion, are regulated by the brain. Similarly, the gut also plays a crucial role in controlling certain functions of the brain by absorbing essential nutrients, maintaining a healthy microbiome and neurotransmitters 

How Does the Brain Affect the Gut?

Your brain, based on the signals it has received, learned, and processed over the years, determines when you should eat meals. It sends signals to the gut at your regular mealtimes, causing you to experience what we call hunger pangs.

In addition, when you are stressed due to factors such as academic pressure, strained relationships, or the lack of work-life balance, it results in an imbalance of certain neurotransmitters and stress hormones like cortisol. The unfavorable balance of these neurotransmitters and hormones can create an adverse effect on your gut functions.

Stress (or depression or other psychological factors) can affect movement and contractions of the GI tract. This is why you might get a bout of diarrhea or constipation under stress.The increase in the level of cortisol is also what is responsible for the gut-wrenching experience or nausea that we often feel when we are nervous.

How Does the Gut Affect the Brain?

Neurotransmitters, including serotonin, norepinephrine, epinephrine, and dopamine, can play an important role in regulating the gut-brain axis.

The brain-gut axis comprises a network that establishes two-way communication between the two organs wherein serotonin acts as a critical signaling regulator to modulate physiological functions, such as gastric secretion and regulation of body temperature control. Moreover, dysfunctions associated with serotonin in the gastrointestinal system can affect brain function, especially those involved in sleep, mood, and behavior. [2]

When you eat food, the muscle fibers in the walls of the stomach are stretched. This sends signals to the brain that you have eaten enough, which gives a feeling of satiety and refrains you from eating further.

The act of eating also prevents anger and irritation associated with hunger and lifts your mood. [2]

The Vagus nerve that establishes the connection between the gut and the brain not only regulates your appetite but also controls your mood. [3]

Your gut also helps to support brain functions by absorbing nutrients such as vitamins, minerals, and antioxidants. It nourishes the brain and promotes cognitive functions such as memory, attention span, concentration, and focus.

This is how the gut-brain axis works both ways, allowing these two vital organs to influence and regulate each other’s functions.

What is the Gut Microbiome?

The gut is home to a range of bacteria and other microorganisms that together make up the gut microbiome.

The healthy bacteria residing in the gut play a key role in almost all aspects of our health, including our energy levels, immune responses against harmful pathogens, cognitive functions such as memory and attention span, as well as our emotional wellness.

The gut bacteria have the ability to communicate with the brain and receive signals from it. The essential functions of the gut microbiome include protecting the body against infections, regulating immune system responses, and supporting brain functions.

What is the Role of Gut Microbiome in Mental Health?

The gut microbiome can influence your mental health, primarily through the activities of neurotransmitters.

The gut produces chemicals called neurotransmitters. These chemicals act as messengers that are sent and received by brain cells called neurons. These neurotransmitters control most functions of the brain and help regulate our emotions, actions, thoughts, and responses to favorable or stressful situations.

What makes gut microbiome a key element in influencing our emotional wellness is that the hormonal imbalances implicated in triggering depression and anxiety are often initiated as a result of gut dysbiosis. [4]

It has been found that the gut produces more than 30 neurotransmitters that control our moods, actions, and thoughts. Also, the hormones released by the gut into the blood circulation can cross the blood-brain barrier. These hormones and neurotransmitters can regulate our food intake and appetite and influence our risk of psychiatric and gastrointestinal disorders, such as depression, posttraumatic stress disorder (PTSD), and inflammatory bowel disease (IBD). [5] [6]

This marks the importance of making an effort to improve your gut health and address food sensitivities in order to enhance your mental health and reduce your risk of depression and other psychiatric and gastrointestinal disorders.

What are Food Sensitivities?

Food sensitivity refers to the inflammatory response of the gut to some specific foods. [7]

Food sensitivities are the common cause of inflammation in the gut. Inflammation caused by food sensitivity can increase the risk of several chronic digestive issues, including leaky gut, IBS (irritable bowel syndrome), and IBD.

Inflammation is actually a protective mechanism of the body meant to help you fight, destroy, and eliminate unwanted substances. However, repeated or regular intake of foods to which you are sensitive can cause gut inflammation to persist for a longer duration, due to which you may develop chronic digestive conditions.

Some common foods known to trigger the symptoms of sensitivity include gluten and dairy. Some other foods that can cause food intolerances, allergies, and sensitivity include:

  • Nuts such as peanuts, pecans, walnuts, and almonds
  • Eggs, particularly egg yolks
  • Fish, particularly shellfish
  • Mushrooms
  • Soy
  • FODMAP foods (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols).

Common Symptoms of Food Sensitivities

The inflammatory reaction of the gut is characterized by pain, swelling, and redness of the mucosal lining of the intestine. As a result, you may develop symptoms such as discomfort, pain, loose motions, indigestion, bloating, nausea, flatulence, irregular bowel movement, and constipation.

If the specific food responsible for causing sensitivity is not identified and eliminated from your diet, it can cause persistent or chronic inflammation in the gut, making you vulnerable to developing chronic digestive disorders. [8]

In addition, you may also develop certain symptoms that do not seem to be directly related to the digestive system. These ‘hidden’ symptoms of food sensitivities include:

  • Feeling weak and sluggish
  • Lack of sleep
  • Frequent headaches or migraine attacks
  • Lethargy
  • Weight loss or inability to lose weight
  • Reduced focus
  • Eczema
  • Rheumatoid arthritis, psoriasis, and other autoimmune disease

How are Food Sensitivities and Mental Health Associated?

Food sensitivity can affect the balance of healthy strains of bacteria in the gut and increase the risk of chronic digestive issues such as IBD and IBS.

Though the blood-brain barrier limits the entry of immune cells into the brain, the increase in the leukocyte count in the central nervous system associated with the immune system response to food sensitivity can contribute to significant inflammation of the neurons. The neuroinflammation, thus induced, can further impair the blood-brain barrier, allowing more immune cells to enter the central nervous system, creating a vicious cycle that escalates neuroinflammation.

This can trigger the activation of mast cells and microglia cells. The increase in the activity of these cells during an allergic reaction can result in several forms of behavioral dysfunction.

It can also affect your cognitive functions and immune system responses, resulting in serious consequences affecting physical and mental health.

Researchers have discovered that the incidence of depression and anxiety is higher in patients diagnosed with certain digestive disorders, such as inflammatory bowel disease.

The findings of the research have also revealed that the higher risk of depression and anxiety is not just secondary to the diagnosis of IBD. On the contrary, IBD can actually be an independent precursor for depression and also the predictor of the severity of the symptoms of this mental health condition. [9]

This means having IBD could increase your chances of developing depression and anxiety significantly due to the involvement of the poor gut microbiome.

Other than depression and anxiety, changes and imbalances in your gut microbiome and the pre-existing chronic digestive conditions can also make you vulnerable to developing other mental health disorders, including:

  • Alzheimer’s disease
  • Schizophrenia
  • Dementia
  • Bipolar disorder
  • Post-traumatic stress disorder
  • Obsessive-compulsive disorder
  • Attention-deficit/hyperactivity disorder
  • Autism

These facts strongly point to the need to seek timely interventions to manage food sensitivities and correct gut dysbiosis in order to improve your emotional wellness and reduce the risk of mental health issues.

You can consult your functional medicine expert to find the most appropriate food sensitivity test, gut microbiome test, supplements, nutrition, and lifestyle strategies suitable for you to manage food sensitivity and improve your gut microbiome to help restore optimum physical and mental health. 

Management of Food Sensitivity 

1. Eat a Balanced Diet

A diet rich in vitamins and minerals can promote the functions of the gut as well as the brain. You can consult your functional nutritionist to find the best nutrition plan suitable for you.

2. Elimination Diet 

The elimination diet offers an effective way to identify food triggers responsible for causing sensitivity symptoms. The elimination diet involves tracking your food intake and symptoms so that you can correlate the time of occurrence of the symptoms with the particular foods eaten on those days. [10]

This diet can help you identify the probable foods or ingredients that could be responsible for causing sensitivity. Once you have identified those foods, the next step is to stop eating them in order to prevent abnormal immune responses and lower inflammation.

3. Get an Accurate Food Sensitivity Test 

Most food sensitivity tests have an accuracy between 50 to 95%. Hence, these tests are not completely reliable. The FIT Test is a highly sensitive food test with high accuracy. It uses patented technology to identify food sensitivity. 

The FIT test offers a systematic way for the accurate assessment of the immune system to identify food sensitivities. The assessment of these multiple pathways can enable you to eliminate false positive results.

4. Regular Physical Activity

Regular exercise can help enhance gut functions, thereby producing an indirect positive effect on your brain health and vice versa. Exercise can also improve hormonal balance, promote the secretion of digestive enzymes, and thus strengthen the gut-brain axis.

4. Get Enough Sleep

It is important to ensure you get an undisturbed sleep of at least 8 to 9 hours every night as it can allow your body adequate time to repair and heal the damaged tissues of the brain and gut and restore the normal functions of these organs. 

5. Manage Stress

Taking steps to relieve mental stress and developing a positive attitude can help to restore a healthy balance of hormones, improve immune system functions, and enhance brain functions and gut health

Your functional medicine expert will help you choose appropriate stress-relieving methods, such as yoga and mindfulness practices, to help you avoid stress and reduce your risk of mental health issues.

6. Probiotic Foods 

You can also consume foods rich in prebiotics and probiotics, such as yogurt, kimchi, or kombucha, to improve the diversity of your gut microbiome so that tackling food sensitivity becomes easier.

7. Probiotic, Prebiotic, or Synbiotic Supplementation

You can consider using supplements containing prebiotics and, probiotics, synbiotics to improve your gut microbiota and address food sensitivities by improving leaky gut.

Work with a Functional Medicine Practitioner 

You can also work with a functional medicine practitioner who can suggest to you the right functional medicine protocol to remove food sensitivities and improve gut health and microbiome. Your functional medicine expert will also be able to help you plan your meals such that the foods you eat comprise essential nutrients that can heal the gut, improve brain functions, and support immune system functions.

Such a functional medicine protocol will help you avoid foods that cause sensitivities, improve your gut microbiome, and reduce inflammation, which can improve mental health. 


Emerging findings from clinical research suggest that by removing food sensitivities, we can improve gut health and reduce inflammation in our bodies. Good gut health can have a significant positive impact on your emotional wellness and cognitive functions and reduce your risk of depression and other mental health disorders.

Understanding the link between the functions of the brain and the gut can be a stepping stone toward better mental health. You can also consult your functional medicine expert to receive guidance on the most effective functional medicine protocol personalized to you to help you manage food sensitivity, improve the gut-brain axis, boost immunity, and enhance emotional wellness. 

Dr Menka Gupta


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