The Gut-Brain Axis
The ‘Brain-Gut Axis’ refers to the two-way communication system between our digestive tract and the brain. Increasing research on this axis shows the significant influence the gut can have on the brain and vice versa. When discussing reactions to foods, we typically think of them as immediate and often dangerous allergic responses, such as throat constriction, breathing difficulties, or dizziness and fainting.
Identifying the food responsible for these reactions is typically straightforward due to the prompt response from the immune system, triggered by a type of immune cell called Immunoglobulin E (IgE). IgE is a protein generated by the immune system to combat foreign substances like allergens, viruses, and bacteria.
Conversely, food intolerances involve IgG antibodies, and these reactions may take up to 48 hours to manifest. Symptoms linked to IgG reactions frequently appear as chronic problems such as joint pain, IBS, and depression or anxiety, which are often ignored and not connected to our diet.
The Impact of Bacteria on Gut-Brain Communication
The communication between the gut and the brain is regulated by our immune system, endocrine system (hormones), and central nervous system, all of which are influenced by the bacteria in our gut. The types and quantities of these bacteria, referred to as our gut microbiome, can be directly affected by factors like diet, stress, pollution, and medications. Additionally, the microbiome's composition is known to influence an individual's susceptibility to food sensitivities and intolerances.
Leaky Gut = Leaky Brain
To gain a deeper understanding of how food intolerances may affect our mental health, it's essential to delve into the connection between our gut microbiome, the immune system, and our brain. The lining of our digestive tract acts as a barrier between the food we consume and the rest of our body. An unhealthy gut microbiome can result in elevated inflammation levels, making the walls susceptible to structural damage. Keep in mind that the gut wall is only one cell thick and covers an area equivalent to a tennis court.
The intestinal wall consists of cell junctions that block bacteria and large food molecules from entering the bloodstream. However, if these junctions become damaged, proteins from foods that should not be in our bloodstream can enter, triggering an immune response. This response is mediated by IgG, an antibody that helps protect against bacterial and viral infections as well as food antigens. Although food antigens are typically cleared quickly by a system known as the reticuloendothelial system, a compromised gut structure and microbiome can cause this immune response to persist. It is suggested that such a chronic immune response could negatively affect the brain, harming its structural barrier, known as the Blood Brain Barrier.
The Brain’s High Fortress – The Blood Brain Barrier
The Blood Brain Barrier (BBB) resembles the structure of the intestinal barrier and is typically highly selective, permitting certain essential metabolic substances, like short chain fatty acids and amino acids, to enter the brain from the broader circulation while safeguarding the brain from potentially harmful elements. If the BBB is compromised, undesirable translocation might occur, such as allowing bacterial invasion, which can alter the function of immune cells responsible for regulating inflammation. Chronic inflammation is linked to numerous mental and physical health issues, suggesting that poor gut health can directly relate to poor mental wellbeing. This is due to a compromised intestinal barrier and its negative impact on our brain's structural barrier (BBB), leading to inflammation.
The Link Between Inflammation and Depression
Extensive studies have demonstrated the link between chronic low-grade inflammation and depression. For instance, in a study that analyzed data from 14,275 individuals interviewed between 2007 and 2012, it was found that those with depression had 46% higher levels of C-reactive protein (CRP), an indicator of inflammatory disease, in their blood samples. Research like this is advancing our understanding of the pathology of mental health disorders and how factors like diet and stress can affect bodily systems, such as digestive function, thereby influencing mental wellbeing.
Testing for IgG antibodies in food intolerance assessments has become a popular approach to addressing symptoms linked to sensitivities like IBS, joint pain, fatigue, migraines, anxiety, and depression. A recent survey involving 708 participants, commissioned by Allergy UK, revealed that 81% of individuals with high IgG levels and psychological symptoms experienced improvement in their condition after adhering to a food-specific IgG elimination diet. Considering this, health professionals and individuals with mental health challenges might explore the potential impact of food intolerances on mental well-being and the management of common mood-related disorders, such as depression and anxiety.
How to Heal a Leaky Gut
Foods high in collagen and its amino acids, such as glycine and proline, are excellent for repairing connective tissue, which comprises the intestines. Traditional foods, rich in these amino acids, have regained popularity in our kitchens due to their therapeutic benefits. These include fermented foods like kefir, sauerkraut, and kimchi, which are rich in prebiotics, probiotics, and postbiotics—beneficial bacteria that our digestive system needs to maintain balance and protect the intestinal barrier from pathogens, toxins, and parasites. By incorporating these foods into a daily routine alongside a healthy, nutrient-dense diet, it may become possible to cautiously reintroduce foods that previously triggered an IgG response, one at a time, while monitoring symptoms.
References: Food For The Brain Foundation. Gut and Physiology Syndrome.
Coming Up: Understanding Food Addiction and the Benefits of Fermented Foods.
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