insights

Read Time: 5 Minutes

According to recent cross-sectional studies, approximately 11% of US adults have one or more food allergies.^1,2 Many foods have been reported to cause reactions, with the greatest burden from major food allergens such as shellfish, milk, peanuts, tree nuts, wheat, and soy.¹ Food intolerances and sensitivities are much more common than allergies, with one study estimating a prevalence of 15-20%.³ Many food intolerances result from difficulty digesting a food due to multiple factors, such as enzyme deficiencies, and they are typically less likely to be immunologically mediated.

Eating the right foods may help reduce inflammation and the risk of illness,^4,5 and exposure to even small amounts of allergenic foods can trigger a range of clinical symptoms. Yet due to the diversity of symptoms and potential delay in response, food reactions can be challenging to diagnose. The gold standard for identifying food allergies is a short-term diagnostic elimination diet.^6,7

IFM’S Elimination Diet & Reintroduction

IFM’s Elimination Diet is a three-week program designed to tailor a person’s diet for their unique physiology, clear the body of foods and chemicals that the patient may be sensitive or allergic to, support the gut microbiome, reduce inflammation, and increase phytonutrient intake. During the program, the patient removes specific foods and categories of foods from their diet. After the three weeks are complete, a careful reintroduction of foods can identify previously hidden food triggers that may have been contributing to illness, causing fatigue, and reducing overall vitality. For patients with anaphylactic, IgE-mediated food allergies, reintroduction should only occur in the presence of trained healthcare professionals. For food reactions including sensitivities and intolerances, reintroduction may often safely occur at home, after the elimination diet has reduced inflammation and stress on the body.

For many patients, the elimination diet has been a cornerstone of identifying a path to increased health;^4,8,9 however, the elimination diet is not suitable for all patients such as constitutionally weak patients, patients with acute illness, those with a history of disordered eating or an active eating disorder, and pregnant women.

Clinicians trained in functional medicine who commonly use IFM’s Elimination Diet report that overall health improves when food triggers are removed and gastrointestinal symptoms and irritation often go down. Successfully reintroducing foods is important, as eating the same few foods day after day does not provide the body with the full array of nutrients necessary for optimal health. A diet with a large diversity of foods helps ensure that the body gets essential nutrients and is especially important for those who have digestive issues.

Efficacy & Clinical Applications

Research on the elimination diet for food sensitivities continues to develop. In a 2013 study evaluating the therapeutic potential of an elimination diet among migraine patients with irritable bowel syndrome (IBS), researchers found that the diet may effectively reduce symptoms from both disorders, with possible positive impact on patients’ quality of life.¹⁰ In one study with patients with diarrhea-dominant or mixed-type IBS, one-third responded positively to a gluten elimination diet.¹¹ A 2019 study suggested that an IgG elimination diet combined with probiotics may be beneficial to migraine patients with IBS.¹²

In patients with atopic dermatitis, research suggests that food allergies and negative food reactions may play a role in the disease.¹³ Short-term elimination diets may benefit at least a subset of these patients^14,15 to identify food allergies potentially involved in disease flares.¹⁶ Research has also suggested that patients with the immune-mediated inflammatory condition eosinophilic esophagitis (EoE) may also benefit from an elimination diet.⁸ A 2022 observational study (n=213 adult patients with EoE) found that after following a six-food elimination diet and food reintroduction program, 69% of participants had one food trigger identified, 24% had two allergens identified, and 4% had three identified.⁵ Milk, wheat, and soy were the most common food triggers.⁵

While the elimination diet can aid in evaluation and treatment, it is important to emphasize that elimination diets are designed to be used short-term. Long-term dietary restrictions have been associated with nutrient deficiencies.¹⁷ In a study of patients with ulcerative colitis and Crohn’s disease, the rate of malnutrition was high, with high rates of deficiency in iron, calcium, vitamin B12, and vitamin D.¹⁸ One of the causes for malnutrition was a dietary adjustment based on the patient’s own experience or belief.¹⁸ The goal of the IFM Elimination Diet is to remove triggers and then return the patient to a wide and varied diet that provides adequate nutrition.

The IFM Elimination Diet has been found to be generally well tolerated, and many individuals have reported increased energy, mental alertness, a decrease in muscle or joint pain, and a general sense of improved well-being. Although short-term, the elimination diet requires careful planning for success. Nutritional changes can necessitate learning new cooking skills and experimenting with new ingredients. IFM’s Elimination Diet is available to all IFM members in the IFM Toolkit, along with a wealth of other resources, including the Food Reintroduction–Symptoms Tracker. This important tool helps practitioners and patients through the process of reintroducing only one new food at a time and assessing the body’s response to that food by keeping track of symptoms.

Learn more about how nutritional and other lifestyle-based interventions may help to address root causes of chronic conditions and improve overall health at IFM’s Applying Functional Medicine in Clinical Practice (AFMCP).

Related Articles

Therapeutic Food Plans: A Component of Personalized Nutrition

The Power of Functional Nutrition

Intestinal Permeability and Inflammatory Triggers

References

1. Gupta RS, Warren CM, Smith BM, et al. Prevalence and severity of food allergies among US adults. JAMA Netw Open. 2019;2(1):e185630. doi:1001/jamanetworkopen.2018.5630
2. Jiang J, Warren CM, Brewer A, Soffer G, Gupta RS. Racial, ethnic, and socioeconomic differences in food allergies in the US. JAMA Netw Open. 2023;6(6):e2318162. doi:1001/jamanetworkopen.2023.18162
3. Lomer MC. Review article: the aetiology, diagnosis, mechanisms and clinical evidence for food intolerance. Aliment Pharmacol Ther. 2015;41(3):262-275. doi:1111/apt.13041
4. Jactel SN, Olson JM, Wolin KY, et al. Efficacy of a digital personalized elimination diet for the self-management of irritable bowel syndrome and comorbid irritable bowel syndrome and inflammatory bowel disease. Clin Transl Gastroenterol. 2023;14(1):e00545. doi:14309/ctg.0000000000000545
5. Zalewski A, Doerfler B, Krause A, Hirano I, Gonsalves N. Long-term outcomes of the Six-Food Elimination Diet and food reintroduction in a large cohort of adults with eosinophilic esophagitis. Am J Gastroenterol. 2022;117(12):1963-1970. doi:14309/ajg.0000000000001949
6. Wood RA. Diagnostic elimination diets and oral food provocation. Chem Immunol Allergy. 2015;101:87-95. doi:1159/000371680
7. Molina-Infante J. Nutritional and psychological considerations for dietary therapy in eosinophilic esophagitis. Nutrients. 2022;14(8):1588. doi:3390/nu14081588
8. Mayerhofer C, Kavallar AM, Aldrian D, Lindner AK, Müller T, Vogel GF. Efficacy of elimination diets in eosinophilic esophagitis: a systematic review and meta-analysis. Clin Gastroenterol Hepatol. 2023;21(9):2197-2210.e3. doi:1016/j.cgh.2023.01.019
9. Ostrowska L, Gier D, Zysk B. The influence of reducing diets on changes in thyroid parameters in women suffering from obesity and Hashimoto’s disease. Nutrients. 2021;13(3):862. doi:3390/nu13030862
10.  Aydinlar EI, Dikmen PY, Tiffikci A, et al. IgG-based elimination diet in migraine plus irritable bowel syndrome. Headache. 2013;53(3):514-525. doi:1111/j.1526-4610.2012.02296.x
11.  Barmeyer C, Schumann M, Meyer T, et al. Long-term response to gluten-free diet as evidence for non-celiac wheat sensitivity in one third of patients with diarrhea-dominant and mixed-type irritable bowel syndrome. Int J Colorectal Dis. 2017;32(1):29-39. doi:1007/s00384-016-2663-x
12.  Xie Y, Zhou G, Xu Y, et al. Effects of diet based on IgG elimination combined with probiotics on migraine plus irritable bowel syndrome. Pain Res Manag. 2019;2019:7890461. doi:1155/2019/7890461
13.  Hui-Beckman JW, Goleva E, Berdyshev E, Leung DYM. Endotypes of atopic dermatitis and food allergy. J Allergy Clin Immunol. 2023;151(1):26-28. doi:1016/j.jaci.2022.07.021
14.  Oykhman P, Dookie J, Al-Rammahy H, et al. Dietary elimination for the treatment of atopic dermatitis: a systematic review and meta-analysis. J Allergy Clin Immunol Pract. 2022;10(10):2657-2666.e8. doi:1016/j.jaip.2022.06.044
15.  Papapostolou N, Xepapadaki P, Gregoriou S, Makris M. Atopic dermatitis and food allergy: a complex interplay what we know and what we would like to learn. J Clin Med. 2022;11(14):4232. doi:3390/jcm11144232
16.  Wollenberg A, Christen-Zäch S, Taieb A, et al. ETFAD/EADV Eczema Task Force 2020 position paper on diagnosis and treatment of atopic dermatitis in adults and children. J Eur Acad Dermatol Venereol. 2020;34(12):2717-2744. doi:1111/jdv.16892
17.  Lim HS, Kim SK, Hong SJ. Food elimination diet and nutritional deficiency in patients with inflammatory bowel disease. Clin Nutr Res. 2018;7(1):48-55. doi:7762/cnr.2018.7.1.48
18.  Nosrati A, Afifi L, Danesh MJ, et al. Dietary modifications in atopic dermatitis: patient-reported outcomes. J Dermatolog Treat. 2017;28(6):523-538. doi:1080/09546634.2016.1278071