IFM’s Elimination Diet: Personalized Optimized Nutrition

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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.

(Video Time: 2 minutes) In the following video, IFM educator Elizabeth Boham, MD, MS, RD, IFMCP, discusses the importance of a careful reintroduction of foods for patients on the elimination diet. Dr. Boham is board certified in family medicine and is a certified IFM practitioner who is on the faculty of The Institute for Functional Medicine. She has a strong background in nutrition and has developed a functional nutrition course that educates physicians and other health professionals worldwide.

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 patients14,15 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).

Learn More About Functional Medicine

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