“More bacteria live and work in one linear centimeter of your lower colon than all the humans who have ever lived … Are we in charge, or are we simply hosts for bacteria? It all depends on your outlook.”
– Neil deGrasse Tyson, Space Chronicles: Facing the Ultimate Frontier
Extra-Intestinal Symptoms of GI Imbalances & Food Reactions
Increasingly, research is linking imbalances in the gut to diseases that may not at first seem connected to gut function. Work by several researchers has linked intestinal mucosal permeability to chronic respiratory allergies/rhinitis,1-2 asthma,3-4 and eczema.5-6 Furthermore, intestinal dysbiosis is known to play a role in many chronic conditions,7 and reactions to food can manifest far from the intestines.8-10
One of the common consequences of food reactions can be headaches and migraines. Headache specialist Robert Sheeler, MD, an IFM certified practitioner, describes the many types of symptoms that can manifest in the presence of food reactions:
Eczema & The Gut
As Dr. Sheeler states, food reactions can also take the form of rashes or skin problems. On first glance, the connection between intestinal mucosal disruption and eczema may seem the most straightforward, as skin microbiome11 and barrier integrity12 are known to be affected in patients with eczema, and the connection between the skin microbiome and the gut microbiome seems intuitive.
Indeed, evidence is accumulating that treatments aimed at restoring balance in the gut microbiome, such as ingesting probiotics, may reduce eczema,13 suggesting that repairing the gut could be key to reducing eczema severity. Furthermore, Staphylococcus aureus on the skin is known to play a role in atopic dermatitis, and an unusual predominance of S. aureus is found on the skin of individuals with the condition.14-15 However, a Cochrane Review recently concluded that “currently available probiotic strains probably make little or no difference in improving patient-rated eczema symptoms.”16 Rather than alter the skin or gut microbiome with supplements, removing inflammatory triggers may be a stronger approach at this time. For instance, “marked improvement” of atopic dermatitis can be seen with removal of food triggers, and the authors also suggest inhalation of allergens may play a role in atopic dermatitis.17
In pediatric patients, eczema and food allergy (IgE-mediated) are highly correlated, with 30% of children with moderate to severe eczema having a food allergy.18 In one study on adult patients with atopic dermatitis, severity of atopic dermatitis correlated with very high IgE reactivity: 92% of patients with severe and 83% of patients with moderate atopic dermatitis showed reactivity.19 This may suggest that poly-sensitization plays a role in the progression of atopic conditions.
Further research has found that atopic dermatitis is a predictive risk factor for food sensitization in infants, further connecting the skin and gut and suggesting that skin dysbiosis or mucosal permeability may potentially precede food reactions in some cases.20
Headaches, Migraines, and Food Reactions
Individuals with chronic gastrointestinal symptoms are more likely to have headaches or migraines.21 The pro-inflammatory immune response associated with intestinal permeability likely plays a role in increasing headache and migraine frequency.21 In one large retrospective study, patients with migraines were more likely to have GERD, and migraineurs and those with tension headaches were more prone to gastric ulcers than the control groups.22
Many patients who suffer from migraines or chronic headaches state that dietary factors play a role.23-24 Dietary triggers tend to be personalized, and interventions need to emphasize overall healthy lifestyle change rather than simply food restriction.25 However, research is suggestive that certain classes of food may be more likely to trigger headaches. For example, one study of 115 children with chronic headaches excluded caffeine, MSG, cocoa, aspartame, cheese, citrus, and nitrates for six weeks.26 At the six-week mark, 87% of the children no longer suffered from headache.26 That research did not follow up with reintroduction of foods to identify which may have been the specific triggers for specific individuals. Three studies have examined how IgG antibody testing may guide exclusion of certain foods, each showing a reduction in headaches when those foods were eliminated.27-29 Only one of those studies also included an intervention to support the gut, in this case by using probiotics.
Even without IgG testing, avoiding patient-identified trigger foods can greatly reduce migraine frequency.30 However, for patients suffering from migraines who wish to avoid medications, short-term elimination of the problem classes of foods may provide relief.
Food reactions can take many forms. From the fabled ice cream headache to foggy-headedness or metabolic responses, food affects the body. Two symptoms that raise the index of concern for potential food reactions are persistent atopic issues and headaches or migraine.
Identifying and treating food reactions can be challenging, due to the range of potential symptoms. In addition to removing potential trigger foods, IFM recommends supporting gut health by reducing inflammation, improving nutritional status, and supporting the microbiome with pre- and/or probiotics. These steps can help reduce immune activation and lead to overall improved health, beyond reducing the symptoms.
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The gut-brain axis is the bidirectional communication between the gut and the brain, which occurs through multiple pathways that include hormonal, neural, and immune mediators. Interestingly, the signals along this axis can originate in the gut, the brain, or both, with the objective of maintaining normal gut function and appropriate behavior.Read More