Food intolerances and allergies are very common and can negatively impact ones health and wellbeing.

Although such sensitivities to food are often thought to be rare, ~10% of people may suffer from some type of food intolerance or allergy [1].

The reason people have these issues usually stems from a genetic predisposition, but may also be from poor gut health which does not enable them to properly digest and absorb certain foods [2].

To get around this issue, elimination diets are the “gold standard” for identifying food sensitivities and are frequently used by dietitians and nutritionists with their clients.

Such a diet is used to pinpoint the food, or foods, that are responsible for causing such health issues and symptoms.

Common symptoms that would usually lead to the implementation of an elimination diet are diarrhea, bloating, constipation, eczema, acne, muscle aches, migraines, fatigue, among many others.

In addition, many people are unaware that untreated food sensitivities can potentially harm the body over time and increase the risk of:

• Nutrient deficiencies
• Chronic fatigue
• Arthritis
• Asthma
• Nutrient deficiencies
• Depression
• Anxiety
• Autoimmune disorders
• Atherosclerosis
• Neurodegenerative diseases
• Kidney problems

What Is The Elimination Diet?

The elimination diet involves strategically removing and reintroducing foods in the diet to identify the root causes of a health issue that is being triggered by a sensitivity to a specific food.

Although an individual can technically be sensitive to any food, there are 8 primary foods that account for ~90% of all food reactions:

• Milk
• Eggs
• Peanuts
• Nuts
• Wheat/gluten
• Soy
• Fish

It is important to note that there are various types of elimination diets that tend to differ slightly, but one commonality is that they all tend to first cut out these most common allergens that are most likely to be the underlying issue.

In total, elimination diets last for about 3-6 weeks. This time period is necessary to allow antibodies to be removed (immune proteins that may negatively reacts to foods) and for the body to fully heal from sensitives.

Quite simply, once a food has been successfully identified as not being well-tolerated, it can be removed from the diet in the future to avoid such symptoms and health issues.

There are two different approaches to elimination diets which are as follows:

The 1-by-1 Method

This method involves removing 1 food from the diet at a time (for at least a month) and noting any improvements in health or symptoms.

The foods to be removed will start from the most likely culprits and then going down to more rare foods. The list of common foods stated above can be used as a starting point (from top to bottom).

This method can easily identify food intolerances, but as foods are only being removed one at a time it could potentially take up to a year to identify these foods.

However, such a method is very unlikely to cause a nutritional deficiency as the diet will not be dramatically changed.

The Reintroduction Method

The method involves removing all the major food sensitive groups from the diet all at once to quickly get rid of the symptoms being experienced.

Once the symptoms have noticeably improved, foods can be reintroduced into the diet. Each food group should be introduced individually over 2–3 days, while looking for symptoms.

If no symptoms are experienced during the reintroduction period, it can be assumed that the food is okay and the next food can begin to be reintroduced.

However, if any negative symptoms are experienced then a trigger food has been successfully identified and this can then be removed from the diet.

To stay motivated during the initially restrictive phase on this method, it is advised to try creating new recipes and experimenting with herbs and spices to increase palatability.

It is also very important for people to note that this method significantly increases the risk for nutritional deficiencies during the elimination period, compared to the “1-by-1” method.

The Potential Benefits of The Elimination Diet

Below we’ve listed everything that we’ve found credible scientific evidence for:

It May Help Inflammatory Bowel Disease

Inflammatory bowel disease is a chronic inflammatory disease that is represented by ulcerative colitis and crohn’s disease.

This problem often results in severe nausea, vomiting, loss of appetite, headaches, and diarrhea.

Certain studies that utilize elimination diets in patients with irritable bowel syndrome have noted a 100% success rate in significantly improving digestive symptoms [3].

Other studies which have researched the extent of benefits have reported a 10-25% improvement in these symptoms [4].

It May Improve Leaky Gut Syndrome

In many cases leaky gut syndrome is the underlying cause of allergic reactions and chronic inflammation.

Leaky gut is defined as damage to the lining of the digestive tract which then allows specific substances to pass through the gut wall and into the bloodstream. This process results in an inflammatory or allergic response from the immune system.

Damage to the gut wall is thought to be caused by an overabundance of bad bacteria, or chronic inflammation, which degrades the mucosal layer on the gut wall [5]

In animal studies, hyperglycemia has shown to drive intestinal barrier permeability through the reprogramming of intestinal epithelial cells and alteration tight junctions. Therefore, eliminating sugar from the diet and reducing glucose metabolism restores barrier function [6].

Another cause of leaky gut can also be a gluten intolerance, as gluten will increase intestinal permeability and cause an immune response in some people [7]. This is because gluten activates a protein called zonulin that is responsible for regulating the tight junctions of the small intestine and allowing or stopping particles from passing through [8]. Eliminating gluten from the diet can help to avoid this problem.

It May Help Skin Conditions

Elimination diets have shown to help with a variety of skin conditions that are usually triggered by different foods:

• Eczema is a group of skin conditions that appear as red, itchy, cracked, and inflamed skin. Several studies have found that elimination diets may reduce symptoms of eczema [9]. For example, one study found that an elimination diet helped 14 of 15 people with eczema reduce their symptoms and identify their trigger foods [10].
• Acne is a skin condition characterized by red pimples on the skin. Compelling evidence shows that high glycemic foods and dairy products may exacerbate acne [11].

It May Help Migraines

Migraines are a headache that typically affects one side of the head and is often accompanied by nausea.

The causes of migraines are still unclear, but studies have shown that inflammation could be a trigger [12]. Such inflammation may be caused by an immune response from ingesting a food that someone is sensitive towards.

An elimination diet removes foods that cause inflammation and has been shown to reduce chronic migraines. Specifically, studies in this area have shown:

• 33% of adults with frequent migraines have a reduced frequency of headaches after following an elimination diet for just 6 weeks [13].
• Removing common dietary allergens that were identified as part of a pre-screening IgG antibody test significant improves allergic symptoms including migraines [14].
• The gut can influence the blood brain barrier, allow small molecules to permeate barrier systems, and thus influence inflammatory levels. This has been termed “leaky gut, leaky brain” [15].

The Negatives of The Elimination Diet

Like anything, there are some drawbacks you should be aware of:

There’s The Potential for Nutrient Deficiencies

Eliminating major food groups from the diet, even for short periods, may result in micronutrient deficiencies and thus negative health outcomes.

Depending on the food groups being removed, various micronutrients may be at risk of insufficient intake.

However, the main takeaway point is that the more food groups removed from the diet at one time, the more likely one will suffer from deficiencies.

For this reason, the 1-by-1 method is a safer approach to an elimination diet when compared to the reintroduction method.

Conclusion

Elimination diets involves strategically removing and reintroducing foods in the diet to identify the root causes of a health issue that is being triggered by a sensitivity to a specific food.

The research behind these methods is extensive, and elimination diets can help inflammatory bowel disease, leaky gut syndrome, skin conditions, migraines, among others.

It is best to go about elimination diets by strategically removing one food group at a time and noticing the benefits, as opposed to eliminating a large amount of food groups and reintroducing them one by one.

The latter is more likely to result in nutrient deficiencies which are avoidable by taking a more modest approach.