If you've ever had an itchy throat after eating pineapple, or broken out in a rash after munching on a handful of peanuts, you've likely experienced firsthand what it feels like to have an allergic reaction to food. Around 15 million Americans are afflicted by food allergies, making them fairly commonplace in the United States (1). But what about food sensitivities? Research is showing that food sensitivities are on the rise, affecting more people than previously believed (1). Additionally, they could be related to a number of conditions and chronic diseases such as migraine headaches, irritable bowel syndrome, and even obesity (2, 3, 4). Identifying and eliminating certain foods that cause inflammation in one's diet can lead to a reduction in negative symptoms for certain conditions, favoring evidence that suggests the benefits of food sensitivity testing (2, 3, 4, 6).
Food Allergy vs. Food Sensitivity -- What's the Difference?
While the phrases food allergy and food sensitivity have been used interchangeably in the past, they're actually quite different: Food allergies are abnormal immune responses to certain foods that the body sees as harmful, resulting in the body producing antibodies to "fight off" foods. This causes the release of histamine chemicals in the body, causing an inflammatory reaction that we categorize as an allergic reaction (5). Food allergies are triggered almost immediately after consuming a certain food, and can even affect individuals when consumed in trace amounts (think peanuts) and can be life-threatening (5).
Food sensitivities, on the other hand, are a little trickier to diagnose, as the symptoms, reactions and causes can be hard to identify right off the bat. Although often equated with food allergies, food sensitivities invoke a different pathway of the immune system associated with immunoglobulin G (IgG) rather than immunoglobulin E (IgE), but still invoke similar symptoms and reactions such as irritability of the bowels, upset stomach, rashes and itching (5). Food sensitivities can be hard to pinpoint because the onset of symptoms is usually slower, can last for several hours or days, and can even increase and decrease in strength depending on the amount of food one's ingested (5).
So, what does food sensitivity testing have to do with chronic illnesses or medical conditions like irritable bowel syndrome? More research is showing that testing for sensitivities towards certain foods and then eliminating them can help patients seek relief from painful symptoms without the use of drugs, surgery, or other costly forms of therapy (2, 3, 4, 6).
It's Not All In Your Head: Migraines and Food Sensitivity
While the exact pathophysiological cause of migraines is still unclear, food allergies/sensitivities have long been associated with exacerbating or even causing migraines (2). Now, several studies are showing that significant reductions were made in the number and strength of migraines with exclusion diets, a promising result for people who are afflicted by this debilitating condition (2). In a study conducted by the Istanbul Faculty of Medicine at the University of Istanbul and published in Cephalalgia: An International Journal of Headache, 30 patients diagnosed with migraines were either put on an exclusion diet based on a food sensitivity test, or a sham diet excluding the same number of foods but not those to which they had built antibodies to (2). The study found that an elimination diet resulted in a statistically significant reduction of the symptoms and frequency of migraine attacks, supporting the claim that food sensitivity testing is important for the treatment of migraine headaches (2).
In a similar study conducted by the Center of Immunology and Allergies in Mexico, serum antibodies to 108 specific food allergens were measured in 56 patients with migraines versus a control group without migraines (6). The study proved interesting for the benefits of food sensitivity testing twofold: Not only did research show that those in the migraine group tested significantly higher for food allergens than the control group, but that elimination diets also reduced migraine frequency and strength without the aid of pharmaceuticals or other forms of therapy (6). Researchers in both instances agreed that food sensitivity testing is important, especially if patients want to reduce their symptoms without pharmaceuticals, which pose a number of side effects in addition to being costly for patients.
What's In My Gut? IBS and Food Intolerance
Food sensitivity testing has also proven to improve the symptoms and lives of those who suffer from the gastrointestinal disorder called irritable bowel syndrome (IBS) (3). IBS is a condition characterized by abdominal pain and bowel dysfunction like constipation, diarrhea and even a fluctuation between these two extremes (3). As the most commonly diagnosed functional gastrointestinal disorder worldwide, about 10-15 percent of Americans suffer from IBS, experiencing a range of mild to severe symptoms that can be physically and emotionally debilitating (7).
Treatment of IBS is mostly limited to medications that alter bowel habits, but many patients believe that intolerances to certain foods are to blame when it comes to their symptomology. In the past, testing for food intolerance was limited to allergy tests, which looked for antibody responses and weren't always conclusive when it came to IBS sufferers (3). In other words, patients with IBS determined that their symptoms were not from allergic reactions, as their irritability and pain wasn't triggered immediately after the intake of a certain food, but was multifactorial and included non-specific symptomatology. Researchers at the University Hospital of South Manchester administered a three-month diet to 150 patients, either exposing them to a diet excluding foods they tested positive for sensitivity, or a sham diet excluding the same number of foods but not to those that they were sensitive to (3). After 12 weeks, patients in the exclusion diet group reported a 10 percent reduction in symptoms than the sham diet group, reporting that the severity of their pain and irritability had reduced; for 52 of the patients who followed the exclusion diet perfectly, a 26 percent reduction of symptoms was recorded.
Interestingly, the study also looked at reintroducing the eliminated foods to the food-sensitive group of participants after the 12-week data and found that IBS symptom severity worsened by 24 percent. This showed a complete reversal of the results observed during the initial treatment phase, further providing evidence that food sensitivity testing is vital to assessing and reducing painful symptoms for sufferers of IBS (3).
The Surprising Connection Between Food Sensitivity and Body Composition
Obesity and its related diseases (diabetes, cardiovascular disease) account for a majority of deaths in the United States, making up 40 percent of all deaths nationally and 75 percent of the country's medical costs, despite the fact that it is a completely preventable disease (4). While the obesity epidemic is multifaceted and multifactorial, much of the attention over the past few decades has been on the correlation between poor diet and obesity -- those who intake high-calorie and processed foods are more likely to be obese than those who maintain a diet low in carbohydrates and fat and full of fresh foods. While this certainly does contribute to obesity, researchers from the Miller School of Medicine at the University of Miami have now linked food sensitivities to obesity, citing a reduction in weight, body mass index, waist and hip circumference, and resting diastolic blood pressure after participants underwent food sensitivity testing and eliminated certain inflammatory foods from their diet (4).
Why is this important for the future of the obesity epidemic? Not only does understanding that food sensitivities impact obesity and could act as an important data point for scientists looking to combat it in the long term, but it also gives obese people a different way to approach their disease and ultimately overcome it. Patients who are informed of their food sensitivities more rigorously avoid these foods because they know exactly which foods worsen their condition -- according to the University of Miami study, participants noted significant improvements in vitality, bodily pain, and general health after avoiding foods they tested sensitive towards in addition to reporting very high compliance to the exclusion diet. With 95 percent of patients in adherence, informed patients stuck to their diets better than researchers predicted (4).
The Future Of Food Sensitivity Testing
What does this mean for the future of food sensitivity testing? Though food allergy testing was considered the gold standard in the past, addressing food sensitivities may prove to be increasingly beneficial for a patient's health in the long run. While migraine, IBS and obesity cases have shown promising results in support of food sensitivity tests, more research needs to be done on this matter to truly confirm the benefits of this method of treatment.
1. "Food Allergy Basics: Facts and Statistics," Food Allergy Research and Education, https://www.foodallergy.org/facts-and-stats
2. Alpay K, Ertaş M, Orhan EK, Üstay DK, Lieners C, Baykan B. Diet restriction in migraine, based on IgG against foods: A clinical double-blind, randomised, cross-over trial. Cephalalgia . 2010;30(7):829-837. doi:10.1177/0333102410361404.
3. Atkinson W. Food elimination based on IgG antibodies in irritable bowel syndrome: a randomised controlled trial. Gut. 2004;53(10):1459-1464. doi:10.1136/gut.2003.037697.
4. Lewis JE, Woolger JM, Melillo A, Alonso Y, Rafatjah S, et al. (2012) Eliminating immunologically-reactive foods from the diet and its effect on body composition and quality of life in overweight persons. J Obes Weig los Ther 2:112. doi:10.4172/2165-7904.1000112
5. "Food Intolerance and Sensitivity," British Allergy Foundation, https://www.allergyuk.org/intolerance-and-sensitivity-menu/intolerance-and-sensitivity
6. Arroyave Hernández CM, Echavarría Pinto M, Hernández Montiel HL. Food allergy mediated by IgG antibodies associated with migraine in adults. Rev Alerg Mex. 2007: Sep-Oct;54(5):162-8. PMID: 18693538
7. 2. Hungin A, Chang L, Locke G, Dennis E, Barghout V. Irritable bowel syndrome in the United States: prevalence, symptom patterns and impact. Alimentary Pharmacology and Therapeutics. 2005;21(11):1365-1375. doi:10.1111/j.1365-2036.2005.02463.x.