Do You Have Leaky Brain Syndrome?
Brain permeability is linked to depression and other mental health problems. How to mend the gaps.
VGstockstudio / Shutterstock Your brain is like a powerful command center, surrounded by a wall to prevent enemy elements from breaching security. Damage to the wall undermines the strength of the command center. The blood-brain barrier is that wall. If compromised, the brain is left vulnerable to assault and subsequent mental health problems.
“Leaky brain” may sound comically implausible, but increased permeability of the blood-brain barrier (BBB) is a well-known phenomenon in neuroscience.
The role of the blood-brain barrier
You may be familiar with leaky gut syndrome. This is where the gut lining becomes damaged, and all sorts of undesirables — toxins, undigested food particles, bacteria — are able to pass from the gut into the blood, creating any number of health issues, ranging from skin disorders to mental fog.
The role of the gut epithelium is to act as a barrier between the gut and the rest of the body. Just like the gut epithelium, the role of the BBB is to be selective about what passes through to the brain and to block harmful substances, including heavy metals, bacteria, viruses, and environmental toxins.
Some substances are meant to cross over the BBB, and they do so with the help of specialist transport proteins. These substances include nutrients, oxygen, amino acids, and glucose.
Both the gut epithelium and the BBB are comprised of just a single layer of cells, held together by structures called tight junctions.
“The junctional proteins in the brain are similar to those of the small intestine.”
How does the brain become leaky?
What causes a leaky gut can also cause a leaky brain. At the top of the list, in both cases, is inflammation.
If inflammation is present anywhere in the body it can affect the brain by disrupting the BBB, altering its integrity by weakening the tight junctions. Inflammatory substances called cytokines that are produced in the gut are able to increase BBB permeability and reach the brain.
Low-grade inflammation is alarmingly widespread, affecting around 40% of people in Western countries. One potential cause of inflammation is metabolic syndrome, a cluster of symptoms that include overweight (especially central obesity), high blood pressure, and high blood fat. Metabolic syndrome can lead to type 2 diabetes, which is also a cause of low-grade inflammation.
“The association between high-grade inflammatory responses such as meningitis, encephalitis, sepsis, local and systemic infections and increased permeability of the BBB for many substances and immune cells has been widely acknowledged”
Another potential cause of inflammation and a damaged BBB is gluten.
Coeliac disease, an autoimmune disease, is the “archetypal leaky syndrome”. It is characterized by inflammation of the gut mucosa caused by a reaction to gluten and gliadin proteins found in wheat, barley, and rye. Although essentially a gut disorder, it can profoundly affect the brain, which is why there may also be seizures, headaches, cognitive impairment, and neuropsychiatric diseases.
Although coeliac disease has a relatively low prevalence, its occurrence is increasing. It is estimated that over 2 million people in the USA have the condition.
You don’t have to have coeliac disease to have gluten sensitivity. “Non-coeliac gluten sensitivity” (NCGS) is "…a combination of gastrointestinal symptoms including abdominal pain, bloating, bowel habit abnormalities (either diarrhea or constipation), and systemic manifestations including disorders of the neuropsychiatric area such as “foggy mind”, depression, headache, fatigue, and leg or arm numbness.”
It is impossible to say how many people are unknowingly affected by NCGS. It is estimated that the prevalence of NCGS among people with irritable bowel syndrome is about 28%. Women seem to be affected more than men.
Many studies have confirmed that gluten leads to the neuroinflammation behind many psychiatric disorders. Gluten elevates a protein called zonulin, which increases inflammation and BBB permeability, and loosens the tight junctions.
Other potential culprits in leaky brain syndrome include excess alcohol intake, bacteria (as in bacterial meningitis), and mycotoxins — metabolites produced by certain fungi that affect the integrity of the BBB and cause neurological damage.
What are the consequences of leaky brain?
“A dysfunction of the blood-brain barrier leading to a ‘leaky brain’ can be linked to various neurological diseases, including autistic spectrum disorder (ASD), dementia, Alzheimer’s disease, depression, and schizophrenia”
It can also be linked to stroke and Parkinson’s disease. Other signs and symptoms include “foggy” brain, poor concentration, chronic fatigue, headaches, memory loss, and cognitive decline.
Screening for a leaky brain
Testing for a leaky gut is relatively easy: you just do a simple urine test that provides what is essentially a yes or no response. Unfortunately, there is no way of testing directly for a leaky brain. There are, however, certain indirect methods of assessing the brain’s permeability. These include:
- Testing for high homocysteine, a protein that is associated with low vitamin B12 and folate and is linked to BBB damage.
- Testing for high levels of the neurotransmitter GABA. Small amounts of GABA cross the BBB. An EEG can show if there is an excessive quantity of GABA making its way into the brain.
- Testing for antibodies against the proteins occludin and zonulin can help determine both brain and gut permeability.
- High blood sugar is also a risk factor, so a glycated hemoglobin (HbA1c) test, which looks at overall blood sugar control, may be useful.
What to do about leaky brain: Six essential steps
First, heal a leaky gut if this is the source of your leaky brain. I wrote about my own experience of leaky gut in this article:
1. First, heal a leaky gut if this is the source of your leaky brain. I wrote about my own experience of leaky gut in this article:
2. Avoid gluten-containing grains: wheat, rye, barley.
3. Avoid sugar and refined carbohydrates. Glucose is a well-known pro-inflammatory agent.
4. Avoid excessive alcohol intake, a cause of both leaky gut and leaky brain.
5. Get sufficient sleep. Melatonin is the sleep hormone, and there is increasing evidence that it can strengthen the BBB and reduce inflammation in the brain.
6. Exercise regularly. Physical activity reduces inflammation and increases blood flow. It has beneficial effects on blood sugar control and blood pressure. Exercise has also been shown to maintain BBB integrity.
“There is a body of evidence that regular physical exercise diminishes BBB permeability… and has anti-inflammatory effects.”
These six steps serve to illustrate just how interconnected every system of the body is and how mental health is about the body as much as the mind. The health of the gut determines the health of the brain, and exercise strengthens not just your heart and lungs but also your blood-brain barrier.
Maria Cross MSc has been a nutrition consultant since 1994. She spent eight years as a university lecturer and tutor, helping set up the first BSc nutritional therapy degree clinic in the UK, and has published two books. Today, Maria divides her time between seeing clients and writing, and is currently working on a book about diet and mental health.