The Truth About The AIP Diet

As described in a 2019 study published in Cureus, the autoimmune protocol (AIP) diet is a variation of the Paleo diet, designed to reduce intestinal and systemic inflammation and modify the body's immune response. The Paleo diet mimics the foods eaten by our hunter-gatherer ancestors living during the Paleolithic period, including meats, fish, fruits, vegetables, nuts and seeds (via the Mayo Clinic). Conversely, foods that were introduced into the human diet with the advent of agriculture around 10,000 years ago (e.g., grains, legumes, dairy) are restricted. The AIP diet, per the study, restricts additional foods (e.g., eggs, nuts and seeds) that can potentially trigger inflammation while focusing on eating nutrient-dense whole foods such as vegetables, fruits, tubers, unprocessed meats, and organ meats. 

Autoimmune disorders are characterized by a faulty immune system that mistakenly attacks the body's own healthy cells and tissues, reports Today's Dietitian. Twice as common among females than among males, autoimmune diseases include celiac disease, inflammatory bowel disease (IBD), lupus, Sjogren's syndrome, psoriasis, type 1 diabetes, multiple sclerosis (MS), rheumatoid arthritis (RA), and Hashimoto's thyroiditis. While there is probably a genetic component to autoimmune disease, diet is a key factor as well. Processed foods high in calories and sugar can promote inflammation and autoimmunity, while sensitivities to specific foods (e.g., nightshade vegetables) can further trigger autoimmune disease. Research indicates that two autoimmune disorders in particular — IBD and Hashimoto's thyroiditis — improve with the AIP diet via reduced intestinal inflammation and better quality of life, respectively. 

As reported by WebMD, many of the foods that should be avoided on the AIP diet are otherwise healthy foods such as grains, legumes, nuts, seeds, dairy, and eggs. On the other hand, the removal from the diet of processed foods, artificial sweeteners, and some vegetable oils is a wise strategy regardless of the AIP diet. Also prohibited are canned or dried fruits, chocolate, tapioca, and various herbs such as mustard seeds, coriander seeds, and fenugreek. 

Per Medical News Today, vegetables in the nightshade family (including potatoes, tomatoes, peppers, and eggplant) are disallowed on the AIP diet as well. Interestingly, according to the Arthritis Foundation, some people claim that the chemical solanine contained in nightshades worsens their arthritis pain; however, scientific evidence is lacking. 

In addition to the aforementioned foods, popular indulgences, including coffee and alcohol, as well food additives such as refined sugar must be bypassed when following the AIP diet (via Medical News Today).

As described by Healthline, foods may begin to be reintroduced as soon as relief of symptoms has been achieved as a result of the elimination phase. The objective of the reintroduction phase is to pinpoint the specific foods or additives that provoke a recurrence of symptoms. The eliminated foods should be reintroduced slowly, one food at a time, so that any reaction is clearly noted. In order to detect possible delayed reactions, a sufficient time interval (5 to 7 days) between each food reintroduction is important. Foods that trigger symptom flare-ups should be avoided for the long term, while non-reactive foods can be brought back into the diet. Periodically, reintroduction of a reactive food may be repeated since tolerance to foods can improve (or worsen) at a later time.

A person's state of well-being and health status is another important factor that should be addressed when reintroducing foods. Unusually stressful circumstances caused by poor sleep, intense exercise, or infection can trigger inflammation and impact food tolerance, potentially skewing results. Also, special consideration should be given to the reintroduction of dairy. Dairy foods with very low lactose such as hard, aged cheeses or lactose-free milk are recommended for testing so as to distinguish between lactose intolerance and reactions to dairy protein per se. 

U.S. News & World Report suggests beginning the reintroduction phase with foods that are traditionally less reactive, such as egg yolk, legumes, and berries. Foods that are historically more allergenic (e.g., egg whites, nuts and seeds) should be tested later.

One of the most researched applications of the AIP diet is in the treatment of inflammatory bowel disease (IBD), which includes Crohn's disease and ulcerative colitis. In a study published in a 2017 edition of Inflammatory Bowel Diseases, 15 IBD patients who had the disease for an average of 19 years underwent the elimination phase of the AIP diet for six weeks and continued food avoidance for five more weeks. The AIP diet was used as a complementary therapy to medical treatment; nearly half of the participants were on biological therapy. Remarkably, by week 6, 73% of the patients achieved clinical remission and maintained clinical remission throughout the subsequent five weeks. These impressive findings are on par with most drug therapies for IBD. 

In a follow-up analysis published in a 2019 edition of Crohn's and Colitis 360, changes in gene expression induced by the AIP diet were identified in a small subset of patients with ulcerative colitis. These were observed in a total of 324 genes, some of which were associated with reduced inflammation of the intestinal lining (mucosa) and decreased oxidative stress (free radical damage to DNA, proteins, and fats). Other modified genes were linked to healing of the mucosa that involved the synthesis of proteins and fatty acids, as well as DNA repair. 

In addition to clinical remission, substantially improved quality of life has also been achieved in IBD patients from dietary modification via the AIP diet (per a 2019 study in Crohn's and Colitis 360).

The AIP diet is very similar to the Paleo diet. In fact, per WebMD, the AIP diet is alternatively referred to as the autoimmune paleo diet. In a 2015 controlled study in the European Journal of Clinical Nutrition, people with type 2 diabetes were randomized to consume either a Paleo diet or a standard diet based on recommendations by the American Diabetes Association (ADA) for 21 days. The Paleo diet consisted of meat, fish, poultry, eggs, fruits, vegetables, nuts, potatoes, canola oil, mayonnaise, and honey; added salt, cereal grains, legumes, and dairy were excluded. The ADA diet included low-fat dairy, whole grains, legumes, and salt in moderation. Compared with people on the ADA diet, individuals on the Paleo diet experienced greater benefits on glucose control (e.g., lower fasting blood glucose) and on lipid profiles (e.g., serum cholesterol and triglycerides). Moreover, significant improvements in insulin sensitivity in the most insulin-resistant participants were only associated with consumption of the Paleo diet. 

The Paleo diet has also been shown to improve risk factors associated with the development of type 2 diabetes. In a study in a 2009 edition of the European Journal of Clinical Nutrition, short-term consumption of a Paleo diet significantly improved glucose tolerance and insulin sensitivity in healthy, nondiabetic volunteers. These benefits were achieved without weight loss. 

Since the AIP diet is more restrictive than the Paleo diet, it is reasonable to assume that the AIP diet would have similar benefits in both the prevention and management of type 2 diabetes. 

As it is designed to do, the AIP diet can help improve symptoms and manage flare-ups in people with autoimmune disease, per WebMD. An added bonus of the AIP diet is weight loss, if desired. The elimination of refined sugar and highly processed, calorie-rich foods is certainly conducive to losing unwanted body fat.

As noted by U.S. News & World Report, the AIP diet does not restrict high-quality protein foods such as meat and seafood, nor does it limit fiber-rich fruits and vegetables (except nightshades). Quality protein and dietary fiber are important for satiety by providing that full feeling after meals. Greater satiety after meals leads to less snacking on carbs, and more weight loss. Also, taste is not compromised on the AIP diet, since salt is permitted. Himalayan pink salt, Celtic Sea salt, and other unrefined salts are preferred over table salt. 

Lastly, various resources providing helpful tips and information about the AIP diet are readily available. Food guides for removing and reintroducing foods, meal plans and recipes that are AIP-friendly, and even lifestyle and exercise suggestions can be found on various websites that cater to Paleo enthusiasts or people with autoimmune disease. AIP cookbooks, either in print or electronic, are also accessible.