AIP Research Update: A Hashimoto’s AIP Study from Poland
Good news! The Autoimmune Protocol (AIP), an elimination and reintroduction protocol aimed at helping those with autoimmune disease identify food sensitivities and increase nutrient-density, continues to be the focus of medical research investigating its efficacy for specific autoimmune conditions. While AIP has been widely used in the autoimmune community since 2011 (see the History of the AIP Movement), medical research into its efficacy began around 2015, with results of the first pilot study published in 2017. Since then, studies have been conducted using AIP as an intervention for inflammatory bowel disease (Crohn’s and ulcerative colitis), Hashimoto’s thyroiditis, rheumatoid arthritis, eczema, and psoriasis. If you’d like to learn more about previous studies, including what interventions were used and the results, check out the AIP Medical Research Review.
Today I’ll be highlighting the newest AIP medical study, Effects of Autoimmune Protocol (AIP) diet on changes in thyroid parameters in Hashimoto's disease by a research team from Poland, Paulina Ihnatowicz, Jerzy Gębski, and Małgorzata Ewa Drywień [1]. This is the second study that has been conducted so far using AIP as an intervention to manage Hashimoto’s thyroiditis and certainly adds to our knowledge base of how to use the protocol for managing it [2]. Hashimoto’s is not only the most common autoimmune disease, but conventional treatment is rarely successful as many patients find that they continue to have symptoms even though their hormone levels have been “treated to target” [3].
Intervention details
For this study, 28 patients with Hashimoto’s thyroiditis were enrolled, with 20 of them completing the study. The average age was 35, with patients between 23-55 years old. Patients underwent initial testing, surveys, and dietary analysis, and then were prescribed individualized, 12-week dietary plans compliant with Core AIP Elimination. It should be noted that in contrast to prior studies using AIP, there was no use of a transition phase–participants made immediate transitions to the elimination diet [2].
In terms of testing completed at baseline and completion of the study, patients had their height and weight measured in a clinic, had lab draws for thyroid hormones (TSH, total and free hormones) and thyroid antibodies, an ultrasound of the thyroid, and they also completed surveys to capture symptom burden. Prior dietary intake was captured using a survey for analysis and comparison of prescribed AIP meal plans.
After initial testing, each participant was prescribed an individualized, 12-week Core AIP meal plan based on their anthropometrics (height and weight). They were instructed to continue all prescribed medications and supplements as before, and no adjustments were made to doses. Support was offered via monthly group coaching calls.
Results
Energy and macronutrient intake
A comparison of prior diet and prescribed AIP diet showed that energy intake (calories) was roughly the same before and after the study (2,067 to 1,997 calories). In terms of macronutrient intake, protein increased from 16.77% to 24.9% of total calories, which is an increase of roughly 85 to 125 grams per day (based on a 2,000 calorie intake). The increase in protein came primarily from decreased fat intake.
Micronutrient intake
Analysis of nutrient intake via prescribed AIP diet showed there was a broad increase in nutrient density during the intervention. Specific nutrient intake increases included Beta-carotene (550%), fiber (162%), folates (198%), long-chain fatty acids (262%), potassium (196%), vitamin A (341%), vitamin C (886%), with other nutrients like B vitamins, iron, zinc, and magnesium with considerable increases. The authors noted that analysis of some nutrients was complicated by supplementation, specifically magnesium, vitamin C, and potassium.
Biochemical thyroid changes
Blood test analysis showed Thyroid stimulating hormone (TSH) significantly decreased from a mean of 3.72 to 2.69. Free T3 and T4 significantly decreased, although both stayed within reference ranges (3.31 to 2.88; 1.36 to 1.20). Mean anti-TPO antibodies increased (210 to 293) and anti-Tg decreased (317 to 300), although these results did not meet statistical significance.
Physical thyroid changes
A comparison of thyroid ultrasounds before and after intervention showed the right lobe volume decreased by 5% and the left lobe volume decreased by 6%.
Weight and body composition changes
Anthropometric measurements taken before and after intervention showed that mean weight decreased from 69 kg to 65.5 kg (152 lbs to 144 lbs). Mean body fat percentage decreased from 33% to 29.5%, indicating that twice as much weight was lost from fat than muscle.
Symptom burden
Analysis of questionnaires showed a broad improvement of symptoms commonly reported by Hashimoto’s thyroiditis patients. The largest decreases were seen in the following areas:
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Digestive function
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Constipation - 36% to 11% (25% difference)
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Gas - 61% to 21% (35% difference)
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Flatulence - 61% to 29% (32% difference)
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Diarrhea - 29% to 7% (22% difference)
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Abdominal pain - 29% to 14% (15% difference)
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Energy
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Tiredness - 82% to 29% (53% difference)
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Drowsiness - 64% to 21% (43% difference)
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Fatigue - 50% to 11% (39% difference)
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Mental
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Impaired concentration - 71% to 18% (53% difference)
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Headaches - 39% to 11% (28% difference)
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Depression - 29% to 4% (25% difference)
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Pain
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Muscle cramps - 43% to 7% (36% difference)
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Joint pain - 57% to 21% (36% difference)
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Skin
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Hair loss - 64% to 32% (32% difference)
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Skin problems - 57% to 7% (50% difference)
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Dry skin - 71% to 32% (39% difference)
In addition to the above results, the authors provided an analysis of specific nutrient intake associations with all of the measures in the study.
Discussion and takeaways
AIP is an incredibly nutrient-dense diet
This is the first study to provide a detailed analysis of the nutrient-density of Core AIP compared to a standard diet. The analysis showed that Core AIP is especially rich in beta-carotene, retinol, fiber, long-chain fatty acids, B vitamins, and minerals (like iron, magnesium, and potassium). It is important to note that the authors prescribed nutrient-dense foods like fermented foods, cold-water fatty fish, broth, and colorful fruits and vegetables in their meal plans, according to AIP guidelines. We know that these nutrients are essential to a healthy body and immune system, and it is possible that many of the anti-inflammatory and restorative benefits of AIP likely come from this increase in nutrient density. Takeaway: Don’t forget to apply nutrient density in your approach to AIP!
Do we focus on thyroid hormones or symptoms to track progress with Hashimoto’s?
The results of this study were a bit paradoxical in terms of thyroid hormones. It is important to note that patients coming into this study were considered euthyroid, or being within normal thyroid hormone reference ranges. As a functional medicine-trained nutritionist, my view is that this group actually could have been considered subclinical hypothyroid with a mean TSH of 3.72, as functional medicine uses a narrower reference range for TSH (.5 to 3 mU/L, compared to the 0.27 to 4.2 used in the study). By that standard, AIP did an excellent job of bringing TSH down under 3, with a decrease of the mean to 2.62.
The part that is paradoxical are the thyroid hormone results. Free T4 and free T3 saw small but significant changes downward. Usually this would indicate that there is less thyroid hormone available to be used in the tissues and according to the conventional model of thyroid treatment, perhaps cause symptoms. But when we take a look at other indicators of thyroid health used in this study, this doesn’t seem to be a bad thing:
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Thyroid ultrasound showed a decrease in thyroid volume. This is important because thyroid volume is linked to higher autoimmune activity, inflammation, and symptoms in patients with Hashimoto’s thyroiditis.
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Body composition changes indicate positive metabolic changes despite a diet identical in energy density. The mean weight loss was 8 pounds in 12 weeks, with a 4% decrease in body fat percentage.
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Surveys indicate a decrease in Hashimoto’s symptoms.
When we take all of these results together, they seem to suggest an improvement in some of the core areas of concern for patients with Hashimoto’s (thyroid swelling, weight gain, and high symptom burden). The reduction in TSH, which is a signal from the brain indicating it needs the thyroid to produce more hormones, points to the body finding balance and having enough thyroid hormone for metabolic needs. In their own discussion, the study authors theorized that the paradoxical result could be due to an improved nutritional status increasing sensitivity to thyroid hormone in the tissues.
Before we get back to the question on what to focus on when gauging progress with Hashimoto’s, I want to share a couple of features of the disease. First, the only conventional treatment for Hashimoto’s is optimizing hormones with thyroid hormone replacement medication. Second, medical research shows that Hashimoto’s patients often continue to have symptoms even after their hormones are corrected to reference ranges [3].
As a Hashimoto’s patient myself, I find the results of this study incredibly validating that someone with this condition can see a drastic improvement in their symptoms without it being reflected in their hormone levels. While hormone levels are important for tracking and treatment, I’ve always been a proponent of equally valuing symptom burden as a major indicator for progress in managing this disease. Takeaway: Results in decreased thyroid volume, weight loss, and symptom management indicate improved thyroid status, despite paradoxical results in thyroid hormone parameters.
How do these results compare to the results of the first AIP Hashimoto’s pilot study?
There are two major differences between the interventions used in these studies. First, the original AIP Hashimoto’s study used a 6-week transition phase and a 4-week elimination phase [2]. This study did not use a transition phase and had a much longer elimination phase of 12-weeks. Second, the original AIP Hashimoto’s study implemented small changes in lifestyle areas like sleep, stress-management, movement, and connection. This study focused only on the dietary side of AIP.
Both studies saw similar results in terms of symptom burden and improvement of quality of life for patients with Hashimoto’s. In the original AIP Hashimoto’s study, medications were titrated based on thyroid hormone levels and they did not see any changes in hormone or antibody levels, although they did see a trend for reduced medication need by the end of the study [2].
Measures tested between the two studies differed a little. The original AIP Hashimoto’s study did not test anthropometric changes, thyroid volume, or the nutrient comparison of the diets, but they did measure a marker of inflammation, hs-CRP (which decreased by 29%) [2]. This was not included in the Polish study. Takeaway: This new AIP Hashimoto’s study adds to our knowledge about AIP’s efficacy in terms of nutrient density, possibility to decrease thyroid volume, and weight loss.
What about the changes in thyroid antibodies?
Hashimoto’s is an autoimmune disease for which two antibodies are known. This study found an increase in anti-TPO and a decrease in anti-Tg, although these results did not meet statistical significance (meaning the result could not be differentiated from chance 1 out of 20 times).
I want to share my personal view on antibodies based on review of research on this topic and my clinical experience working with Hashimoto’s patients. First, there is research associating antibodies with a higher symptom burden and lower quality of life for Hashimoto’s patients; there is also research showing that antibody levels are not correlated with symptoms. My observation as a clinician is that antibodies are helpful for diagnosis and in the early stages of healing, but do not always line up with symptom burden reported by the patient. I’m an advocate for having them tested and tracked, but not using them to gauge progress outside of other indicators of thyroid optimization (like symptoms or hormone levels). Takeaway: Antibodies should not be a primary marker of disease burden for patients with Hashimoto’s.
Conclusion
This is the second quality study showing AIP is effective as a dietary intervention for managing symptoms that come with Hashimoto’s thyroiditis. I’m really impressed with the work of the Polish team that put this together, especially their attention to nutrient-density and customized meal plans. The addition of thyroid ultrasounds as well as the longer duration of the study are very helpful in understanding more about the physical changes possible as well as the timeline over which patients can expect to see results.
If you or a loved one has Hashimoto’s, I hope you learned some great takeaways from this review!
References
1. Ihnatowicz P, Gębski J, Drywień ME. Effects of Autoimmune Protocol (AIP) diet on changes in thyroid parameters in Hashimoto's disease. Ann Agric Environ Med. 2023;30(3):513-521. doi:10.26444/aaem/166263
2. Abbott RD, Sadowski A, Alt AG. Efficacy of the Autoimmune Protocol Diet as Part of a Multi-disciplinary, Supported Lifestyle Intervention for Hashimoto's Thyroiditis. Cureus. 2019;11(4):e4556. Published 2019 Apr 27. doi:10.7759/cureus.4556
3. Groenewegen KL, Mooij CF, van Trotsenburg ASP. Persisting symptoms in patients with Hashimoto's disease despite normal thyroid hormone levels: Does thyroid autoimmunity play a role? A systematic review. J Transl Autoimmun. 2021;4:100101. Published 2021 Apr 15. doi:10.1016/j.jtauto.2021.100101
