Recent findings between the gut microbiota and the brain suggest that our microbiota can deeply influence our health, brain and potentially even our behaviour.
The microbiota has been associated with several neurological conditions  and it could be playing a role in your migraine condition.
This article reviews evidence for those gut conditions associated with migraine and what you can do about it.
This is part 2 of a 2 part series on the microbiome-gut-brain axis for migraine. If you haven’t seen our first article which explains the microbiota, the microbiome and how it can affect our health and brain, read it first here >>
Below is a review of associations from research studies between migraine and gut conditions.
Headache and Gastrointestinal Symptoms
A HEAD-hunt study in Norway looked at the relationship between gut or gastro-intestinal (GI) symptoms and headache including migraine.  The study included 51,000 people and found a higher prevalence of headache among those who regularly experience GI symptoms compared to the control group without GI complaints.
Researchers found that as the headaches became more frequent so did the number of GI complaints which suggests a correlation between them.
The GI complaints were just as common in those with migraine than in those with headache. Both migraine and other headaches were found to be more common in those who had GI complaints. 
Migraine and Gastroparesis
Gastroparesis is a chronic disorder characterised by a delayed emptying of the stomach. It is a relatively common complication of diabetes.
In a population of patients with this condition, those with recurring symptom patterns had higher incidences of migraine headaches with 47% versus 20%. 
For oral medication like the triptans, migraine associated gastroparesis can hinder absorption in the gut which can reduce or block it’s effectiveness.  This has been found in another study which associated migraine attacks with delayed gastric emptying. 
Migraine and Colic
Infant colic is refers to the inconsolable crying during the first months of a baby’s life. It is defined as crying and fussing for more than 3 hours per day, more than 3 days a week, for more than 3 weeks in an otherwise healthy, well fed infant. 
It can affect many families with an incidence ranging from 5-19%.  Colic is suspected to be caused by abdominal pain but other causes have not been ruled out.
It has been suggested that colic is an early life expression of migraine. 
In a group of 154 infant and mother pairs, those whose mother had a history of migraine were 2.6 times more likely to have colic as infants than those without a maternal history of migraine. 
It has also been shown that infants with abdominal colic have lower intestinal microbiota diversity and stability compared to other infants in the first week of life. 
Some studies have used probiotics to treat or try to prevent colic with variable results. 
Children with migraine are more likely to have experienced infantile colic compared with controls (findings vary from 1.6 to 6.6 times more likely from different studies).
Clearly, there is an association between migraine and infantile colic. Exactly how they affect each other is yet to be uncovered.
Migraine and Irritable Bowel Syndrome
IBS involves abdominal pain, bloating, discomfort and noticeable changes in bowel habits. It is a functional bowel disorder.
Like migraine, the pathophysiology of IBS is still not fully understood.
Those with IBS tend to have increased intestinal permeability also known as leaky gut.
Intestinal permeability refers to cells lining the wall inside the gut which control what material passes through into the bloodstream and what doesn’t. Intestinal permeability deteriorates with more severe IBS symptoms. 
A study involving around 125,000 IBS patients from a large national health insurance database found that the chance of being diagnosed with migraine were 60% higher in those with IBS versus those without IBS. 
Other studies found similar associations with 25-50% of IBS patients having migraine versus just 4-19% in control groups (regular population samples). [24, 25] See this article for a definition of control groups >>
A small clinical trial involving 21 patients in an IgG-based elimination diet given to migraine patients with IBS demonstrated promise.
The study was double blinded, randomised, controlled and a cross-over trial with baseline diet, elimination diet and a provocation diet. Compared to baseline, the elimination diet was associated with a reduction in migraine frequency and severity. 
This study found a significant reduction in IBS complaints, reinforcing the association between the two diseases. 
Migraine and Celiac Disease
Celiac disease occurs when the immune system has an autoimmune reaction against gliadin, the primary protein in gluten. 
This inflammatory reaction can led to intestinal damage, dysfunction and increased intestinal permeability or leaky gut. 
Several studies suggest have found that migraine is 2 to 3 times more common in those with celiac disease versus the control groups. 
Within populations of migraine patients, celiac disease has also been found to be more common. One study found celiac disease in 4.4% of the migraine patients (90 people) versus just 0.4% from the migraine free group (236 people). 
Whilst relatively few people have celiac disease compared to migraine. Many people with migraine may test negative to celiac disease but still find some level of sensitivity or trigger from foods high in gluten.
Those who commonly experience bloating, constipation, fatigue or mental fog after eating gluten may benefit from a gluten free diet or a diet with minimal gluten intake.
Migraine and Inflammatory Bowel Disease
Ulcerative colitis and Crohn’s disease are the most common types of inflammatory bowel disease (IBD). IBD causes defects in the intestinal walls (the epithelial layer) and the gut-based mucus immune system.
Factors that may trigger IBD are antibiotics, NSAIDs, stress and infection. These factors can reduce the mucosal barrier integrity, affect the immune response and change the gut microenvironment making it more vulnerable to inflammation. 
Only two studies could be found that looked at the potential relationship between IBD and migraine. The first, a study facilitated by the Gastroenterology Clinic at the University of North Carolina found that migraine was experienced by 30% of IBD patients.  This is significantly higher than the general population incidence at 18.2% in females and 6.5% in males. 
The study found that migraine was more common amongst Crohn’s disease patients with 36% versus ulcerative colitis patients with 14.8%. 
The second study had IBD patients self report whether they experienced migraine or not compared to controls. Results from this study found that participants were 2.6 times more likely to have migraine. 
To date however, there has not been any evidence yet to demonstrate that an improvement in IBD also delivers a corresponding improvement in migraine. 
How important are these associations between other disorders and migraine?
In his TED talk, Rob Knight (pictured above) is pioneering the study of human microbes. What he reveals is that with "90% accuracy" we can tell if someone is lean or obese just by looking at the microbes in your gut.
Whilst this may not seem very impressive since we only need to look at someone and simply see whether they are lean or obese. Consider this - when your entire human genome is sequenced and you have provided all your DNA, researchers can only tell with 60% accuracy whether you are lean or obese.
Rob concludes: “The three pounds of microbes that you carry around with you might be more important than every single gene you carry around in your genome...”
Leaky gut and migraine
This overview has looked at several gut conditions and there relationship to migraine. Clearly there are significant associations between the gut and migraine. A piece of the puzzle may be our inflammatory immune responses which have been found in intestinal disorders characterised by increased intestinal permeability or leaky gut such as IBS, IBD and celiac disease. 
These enhanced pro-inflammatory immune responses are potentially one of the key links between these inflammatory diseases and migraine. Significant associations have also been reported between migraine and a range of inflammatory disorders such as asthma, obesity, metabolic syndrome, allergies and GI diseases.
Genetic susceptibility can determine where these pro-inflammatory responses occur in the body. For example, in the case of migraine, it may occur on the pain receptors of the trigeminal nerve through the release of inflammatory cytokines (see part 1 for more detail).
Leaky gut and inflammation affect each other. Increased intestinal permeability (leaky gut) can cause inflammation and inflammation can also lead to leaky gut. 
For migraine patients with leaky gut, improving intestinal permeability could improve the migraine condition, although further research is warranted to provide conclusive evidence of this hypothesis.
A group of migraine patients who may particularly benefit are those with food allergies.
Individuals with food allergies have shown to have increased intestinal permeability compared to healthy subjects. 
By contrast, the role of food allergies with migraine is still controversial and according to some researchers there is little evidence showing that avoiding food triggers improves migraines. 
To date, there has been little research interest to study the relationship between migraine and diet. 
After 26 years of migraine and 3 years keeping a diary, I have no doubt that my diet affects my migraine condition. Caution should be taken as I’m only a sample of one and what affects my condition may not necessarily affect someone else.
How to improve or restore your microbiome
Given the number of associations between migraine and the gut. The evidence is mounting rapidly and whilst the science is still catching up, there ways we can improve our microbiome diversity and health.
1) Get dirty
There is a ‘hygiene hypothesis’ that suggests over sanitising your baby; your young child’s environment and preventing exposure to good bacteria and other microorganisms increases susceptibility to allergic diseases. 
There is also a correlation between highly sanitised environments and autoimmune diseases such as diabetes and multiple sclerosis. 
Every parent knows that childcare and daycare centers are breeding grounds for germs. If one child is sick… eventually everyone gets sick. Is this an important part of a child's immune system development?
Scientists are still working out exactly how important allowing children to get dirty is to the child’s immediate immune development as well as the long term protection later in life from autoimmune diseases.
2) Eat Clean
Diet can regulate the gut microbiome by changing the availability of nutrients.
Researcher Lawrence David, Assistant professor at the Duke Institute for Genome Sciences and Policy found that dietary changes caused variations in different kinds of bacteria and genetic expression within days. 
An average US diet consists of an excess of highly refined foods which are mass produced in sterilized environments.
These types of foods reduce bacteria that help control inflammation and stress in the body. Depending on the food, it may even cause inflammation itself.
With greater stress and inflammation comes pain. Patients with gastro intestinal disorders are more sensitive to pain than others.  Avoid inflammatory foods and eat healthy with fresh food.
3) Be aware of stress
Regulating the micriobiome-gut- brain axis is essential for maintain balance in the central nervous system.  Stress upsets this balance or homeostasis.
Our stress responses may also be influenced by our own microbiome, suggesting yet again, another bidirectional relationship at work. 
If your body was a car, then stress is the high speed and aggressive driving of your car. You can drive this way for a short while but not all the time. If you do, over time, you'll wear out the parts and cause bigger problems down the track.
The same principle applies to stress. We are designed biologically to be in fight or flight for only short discrete periods of time. With extended periods of stress we can wear out our own "parts" which can have very serious health consequences.
Chronic exposure to stress has been well documented as a contributor to disease including osteoporosis, IBS, diabetes, hypertension, dyslipidemia and neurodegeneration. 
You might be able to exercise away anxiety, depression and stress.
Exercise releases a cascade of benefits within your body and microbiome. Greater levels of inflammatory protection are released with exercise and the micriobiota produces hormonal-neurotransmitter agents including GABA, noradrenaline, dopamine and serotonin. 
These are powerful, natural feel good neurotransmitters and protective agents, many of which have been shown to be in short supply in migraine patients.
A study involving professional rugby players found that exercise increased gut microbiota richness and diversity. That is, exercise increased the biodiversity in the gut which is a key indicator of microbiome health. 
For some people exercise might be a trigger. This shouldn't stop you from starting small and going for a short walk or doing a gentle yoga class. Gradually build up and use common sense. Running 5 kms without prior training is a recipe for disaster.
Without exercise your life expectancy is shortened. 
5) Use antibiotics with caution
Antibiotics affect the gut microbiota. Different antibiotic agents can cause different changes within the gut and alter the profile or equilibrium of the gut microbiome and immune mechanisms.
The microbiota is our first line of defense against infection and disease. Antibiotics have shown potential to reset the default immune and neuro-hormonal status of the microbiome. This may therefore change an individuals predisposition to related disorders.  It can also damage the microbiome and leave it vulnerable to opportunistic microorganisms.
Antibiotics is like fishing with dynamite. It’s a tool which can destroy more than what you intended. It should be used sparingly as a last resort.
If you really need antibiotics, many health practitioners encourage taking probiotics whilst on a course of antibiotics to minimise damage to your intestinal environment. Try not take them right at the exact same time. Taking a pro-botic and an anti-botic at the exact same time will not deliver the desired effect. Speak to your pharmacist about timing each optimally.
Consuming beneficial living bacteria is known as probiotics. It may one day become therapeutic method of treatment using components of the microbiota for a broad range of conditions.
Today, probiotics are widespread with many unregulated and unsubstantiated health claims. Several probiotic strains have shown to be helpful for specific gastrointenstinal symptoms of IBS. 
The most commonly used probiotic are lactobacilli and bifidovacteria.  The effect of probiotics depends on the species and strain of bacteria.
Certain probiotics have shown to be effective in gut-related diseases but in other clinical trials findings have been inconsistent. This may be due to multiple factors including study population, duration, end-points and the different probiotic strains studied. These multiple factors make conclusive findings for these conditions difficult.
Probiotics has been shown in several studies to improve gut permeability (leaky gut) through different mechanisms.  This can have a beneficial impact for those with migraine. No studies could be found where migraine patients received nutritional therapy solely from probiotics.
An uncontrolled study reported the effects of different probiotics combined with vitamins, mineral, herb and micronutrient supplementation in 40 migraine patients. The research found that 60% of the migraine patients experienced reductions of 50% or more from migraine attacks. 
Caution: When taking probiotics it may actually cause headaches and/or migraine. This is can be an unfortunate side effect of a healthy process underway.
Probiotics may trigger headaches because the good bacteria stimulate the body to eliminate toxins and chemicals such as bad bacteria and yeast residing in the digestive tract. As these toxins exit the body symptoms may be experienced for a few days or a week. Any longer and it may be a sign of more serious infection or candida overgrowth.
To avoid or minimise headaches whilst using probiotics you can lower the dose and gradually build up.
Implications for migraine patients
Our gut and brain is more complex and interconnected that we previously thought.
What we eat and are exposed to can ripple across our gut, microbiome, brain and potentially our migraine condition. It can affect us today, but also potentially years into the future.
Whilst the science is still catching up, it makes sense to ensure that our microbiome is as healthy. That we address any leaky gut issues and ensure sustainable and healthy practices like getting dirty, eating clean, regular exercise, minimizing antibiotics and controlling our response to stress.
Most of those activities also help prevent migraines. Coincidence? Time will tell.
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