Autoimmune Diseases and Nutrition: A Functional Approach

Autoimmune diseases are on the rise globally, and nutrition is increasingly recognized as a powerful tool in managing these complex conditions. Whether you’re living with celiac disease, Hashimoto’s thyroiditis, rheumatoid arthritis, or another autoimmune condition, understanding how food influences your immune system can be transformative. This guide explores the connection between autoimmune diseases and nutrition through a functional approach — one that looks beyond symptom management to address the root causes of immune dysfunction.

By Taissa Castello, registered nutritionist CRN-4 25106120, specialized in autoimmune nutrition, celiac disease, gut health, and food allergies.

Understanding Autoimmune Diseases

In a healthy immune system, your body can distinguish between “self” (your own cells) and “non-self” (invaders like bacteria and viruses). In autoimmune diseases, this distinction breaks down. Your immune system begins attacking your own tissues, causing chronic inflammation and progressive damage.

There are more than 80 recognized autoimmune diseases, affecting an estimated 5-8% of the global population — with a striking predominance in women (approximately 78% of autoimmune patients are female). Some of the most common include:

• Celiac disease — immune attack on the small intestine triggered by gluten
• Hashimoto’s thyroiditis — the most common cause of hypothyroidism
• Graves’ disease — causing hyperthyroidism
• Rheumatoid arthritis (RA) — chronic inflammation of the joints
• Type 1 diabetes — immune destruction of insulin-producing cells
• Lupus (SLE) — systemic inflammation affecting multiple organs
• Multiple sclerosis — damage to the protective coating of nerves
• Inflammatory bowel disease — Crohn’s disease and ulcerative colitis
• Psoriasis — accelerated skin cell turnover causing plaques

One critical concept: autoimmune diseases tend to cluster. If you have one autoimmune condition, your risk of developing another is significantly increased. For example, people with celiac disease have higher rates of Hashimoto’s, type 1 diabetes, and autoimmune liver disease (Fasano, 2012).

“When I work with autoimmune patients, I always look at the whole picture. Autoimmune diseases don’t happen in isolation — there’s always a combination of genetic susceptibility, environmental triggers, and gut health factors. Nutrition gives us powerful levers to influence all three.”

— Taissa Castello, PodIgest

Celiac Disease: The Autoimmune Model

Celiac disease holds a unique position among autoimmune diseases because it is the only autoimmune condition with a known trigger: gluten. This makes it an invaluable model for understanding how environmental factors interact with genetics to drive autoimmunity.

The celiac model demonstrates the three requirements for autoimmune disease development, as proposed by Alessio Fasano:

1. Genetic susceptibility — HLA-DQ2 or HLA-DQ8 genes (necessary but not sufficient)
2. Environmental trigger — gluten exposure
3. Increased intestinal permeability — “leaky gut,” allowing gluten peptides to interact with the immune system

Remove the trigger (gluten), and the autoimmune process stops. The intestine heals. Antibodies normalize. This powerful example demonstrates that modifying environmental factors — including diet — can directly control autoimmune activity.

Hashimoto’s Thyroiditis and Nutrition

Hashimoto’s is the most common autoimmune disease and the leading cause of hypothyroidism. The immune system attacks the thyroid gland, gradually destroying its ability to produce thyroid hormones. Nutritional considerations include:

• Selenium — essential for thyroid hormone metabolism; studies show supplementation can reduce thyroid antibodies
• Iodine — both deficiency and excess can worsen Hashimoto’s; balance is key
• Vitamin D — deficiency is strongly associated with autoimmune thyroid disease
• Iron — needed for thyroid hormone production; deficiency is common in hypothyroidism
• Gluten — there’s a well-documented association between celiac disease and Hashimoto’s; some patients benefit from a gluten-free trial even without celiac diagnosis
• Gut health — SIBO and dysbiosis may contribute to nutrient malabsorption and immune dysregulation in Hashimoto’s patients

Rheumatoid Arthritis and Anti-Inflammatory Nutrition

Rheumatoid arthritis (RA) is a systemic autoimmune disease that primarily affects the joints. Research increasingly supports the role of nutrition in managing RA symptoms and disease activity:

• Mediterranean diet — associated with reduced disease activity, likely due to its anti-inflammatory profile
• Omega-3 fatty acids — shown to reduce joint stiffness and pain in RA patients; may allow reduction in NSAID use
• Elimination diets — some patients identify specific food triggers that exacerbate flares
• Gut microbiome modulation — RA patients show altered gut bacteria, and restoring balance may help modulate immune activity

The Intestinal Permeability Hypothesis (Leaky Gut)

The concept of increased intestinal permeability — commonly called “leaky gut” — has moved from fringe theory to serious scientific investigation. Here’s the simplified version:

Your intestinal lining is normally a selective barrier — it absorbs nutrients while keeping harmful substances out. This barrier is maintained by tight junctions between intestinal cells. When these tight junctions become compromised, larger molecules (bacterial fragments, undigested food proteins, toxins) can pass through the intestinal wall into the bloodstream.

This “leaking” of molecules triggers immune activation and, in genetically susceptible individuals, may contribute to autoimmune disease development. The protein zonulin, identified by Fasano’s research team, is a key regulator of tight junction permeability — and two known triggers for zonulin release are gluten and certain gut bacteria (Fasano, 2012).

Factors that may increase intestinal permeability include:

• Chronic stress
• Excessive alcohol consumption
• NSAIDs (ibuprofen, naproxen) with chronic use
• Gut infections and SIBO
• Highly processed diets high in sugar and additives
• Food allergens (in sensitized individuals)
• Gluten (via zonulin pathway)

“I think of the gut lining as the body’s most important gatekeeper. When it’s intact, it lets the good in and keeps the bad out. When it’s compromised, chaos ensues. So much of autoimmune nutrition comes down to restoring the integrity of that barrier.”

— Taissa Castello, PodIgest

Anti-Inflammatory Nutrition for Autoimmune Conditions

While each autoimmune disease has specific nutritional considerations, several principles apply broadly:

Foods to Emphasize

• Fatty fish (salmon, sardines, mackerel) — rich in anti-inflammatory omega-3s
• Colorful vegetables — packed with antioxidants and phytonutrients
• Leafy greens — high in folate, magnesium, and vitamin K
• Berries — potent anti-inflammatory polyphenols
• Turmeric and ginger — well-studied anti-inflammatory compounds
• Bone broth — contains collagen, glutamine, and glycine that support gut healing
• Extra virgin olive oil — oleocanthal has ibuprofen-like anti-inflammatory effects
• Fermented foods — support microbiome diversity (when tolerated)

Foods to Minimize or Avoid

• Refined sugars — promote inflammation and feed pathogenic bacteria
• Processed seed oils — high in pro-inflammatory omega-6 fatty acids
• Ultra-processed foods — contain emulsifiers and additives that may damage the gut lining
• Excessive alcohol — increases intestinal permeability
• Known personal triggers — identified through elimination protocols

Elimination Protocols for Autoimmune Diseases

Several structured elimination protocols have been developed specifically for autoimmune patients:

The Autoimmune Protocol (AIP)

The AIP is the most well-known elimination diet for autoimmune conditions. It temporarily removes foods that are most likely to drive immune activation:

• Grains (all, including gluten-free)
• Legumes
• Dairy
• Eggs
• Nightshades (tomatoes, peppers, eggplant, potatoes)
• Nuts and seeds
• Refined sugars and oils
• Alcohol and coffee

After a strict elimination phase (typically 30-90 days), foods are reintroduced one at a time to identify individual triggers. Research on AIP has shown improvements in symptoms and inflammatory markers in conditions including Hashimoto’s and inflammatory bowel disease (Abbott et al., 2019).

Important: AIP is a diagnostic tool, not a lifelong diet. The goal is always to reintroduce as many foods as possible. This is where professional guidance is essential — a nutritionist ensures you maintain adequate nutrition during elimination and guides systematic reintroduction.

Key Supplements for Autoimmune Support

While food should always be the foundation, certain supplements have evidence supporting their use in autoimmune conditions:

• Vitamin D — deficiency is common in autoimmune patients; adequate levels support immune regulation. Many patients need higher doses to reach optimal levels (work with a healthcare provider for testing and dosing).
• Omega-3 fatty acids (EPA/DHA) — anti-inflammatory; particularly well-studied in RA and lupus
• Probiotics — specific strains can help modulate immune responses (strain selection matters)
• Glutamine — the primary fuel source for intestinal cells; supports gut barrier repair
• Zinc — essential for immune function and intestinal barrier integrity
• Curcumin — the active compound in turmeric; anti-inflammatory effects demonstrated in multiple autoimmune conditions
• Selenium — particularly important for autoimmune thyroid disease

Always discuss supplementation with your healthcare team. Supplements can interact with medications and are not all appropriate for every autoimmune condition.

Working with a Nutritionist for Autoimmune Conditions

Autoimmune nutrition is highly individual. What works for one person may not work for another, even with the same diagnosis. A specialized nutritionist provides:

• Personalized assessment — evaluating your unique triggers, nutritional status, and health history
• Guided elimination and reintroduction — ensuring safety and nutritional adequacy
• Gut health evaluation — assessing for SIBO, dysbiosis, or permeability issues that may be driving immune activation
• Nutrient optimization — addressing deficiencies common in autoimmune conditions
• Coordination with your medical team — ensuring nutritional strategies complement your medical treatment
• Ongoing support and adjustment — autoimmune management is a journey, not a one-time intervention

If you’re living abroad and looking for a nutritionist who understands both autoimmune nutrition and the unique challenges of navigating health and food in a foreign country, teleconsultation makes expert care possible from anywhere.

Frequently Asked Questions

Can nutrition cure autoimmune diseases?

Nutrition cannot “cure” autoimmune diseases in the sense of eliminating them permanently — with one exception: celiac disease, where complete and lifelong avoidance of gluten halts the autoimmune attack on the intestine, since gluten is the specific trigger. For other autoimmune conditions such as Hashimoto’s, rheumatoid arthritis, or lupus, the mechanisms are more complex and involve genetic susceptibility, environmental triggers, and immune dysregulation that diet alone cannot reverse. That said, nutrition is far from powerless. A well-designed dietary strategy can meaningfully reduce systemic inflammation, correct nutrient deficiencies that worsen symptoms, support gut barrier integrity, and help modulate immune activity. Many patients experience longer remission periods, fewer flares, and better quality of life when nutrition is integrated alongside conventional medical treatment. Some individuals do reach full symptom remission through combined dietary and lifestyle changes, though results vary by condition and person. Because autoimmune management is highly individual, any dietary approach should be developed together with your physician and a qualified nutritionist rather than pursued alone.

Should all autoimmune patients go gluten-free?

No, not necessarily — treating gluten-free as a universal autoimmune protocol oversimplifies a complex picture. Patients with confirmed celiac disease must follow a strict, lifelong gluten-free diet, since even trace exposure can reactivate the autoimmune attack on the gut. For other autoimmune conditions, the evidence is more mixed. A supervised gluten-free trial may bring meaningful benefit to some people, particularly those with elevated celiac markers, Hashimoto’s thyroiditis, or persistent gastrointestinal symptoms suggesting gluten sensitivity or gut permeability issues. However, removing an entire food group carries real tradeoffs: nutritional gaps, social and financial burden, and in some cases, no measurable benefit at all. Self-diagnosing gluten as “the problem” can also delay identifying the actual driver of symptoms. This is why a gluten-free trial should be structured, time-limited, and monitored by a healthcare professional — ideally with proper celiac testing done first, since going gluten-free before testing can produce a false-negative result. Talk with your doctor or nutritionist before making this change.

Is leaky gut a real condition?

Yes, the underlying physiology is real, even though the popular term can be misleading. Increased intestinal permeability — where tight junctions between gut lining cells loosen, allowing bacterial fragments and undigested particles into the bloodstream — is well documented in peer-reviewed literature and can be measured with tools like the lactulose-mannitol test or serum zonulin levels. Researcher Alessio Fasano’s work has been particularly influential in establishing intestinal barrier dysfunction as a legitimate mechanism linked to autoimmune disease development (Fasano, 2012). Where “leaky gut” becomes problematic is in popular health media, where it’s sometimes used as a catch-all explanation or marketed alongside unproven supplement protocols. The scientific reality is more nuanced: increased permeability appears to be one contributing factor among several in autoimmune conditions, not a standalone diagnosis or a quick fix. It remains an active, evolving area of research. If you suspect gut permeability is playing a role in your symptoms, discuss appropriate testing with your doctor or nutritionist.

How long does it take for dietary changes to show results?

Timelines vary considerably depending on the condition, its severity, and individual factors like adherence and gut health at baseline, so it helps to set realistic expectations. Many patients notice subjective improvements — less bloating, more energy, reduced joint pain — within two to four weeks of consistent dietary changes. Objective markers move more slowly: inflammatory markers such as CRP typically take three to six months to show meaningful shifts, since the body needs time to down-regulate chronic inflammatory pathways. Autoimmune antibody levels, which reflect the underlying immune attack rather than symptoms alone, can take even longer — often six to twelve months of sustained changes before a significant reduction appears on lab work, and in some conditions they never fully normalize. Because progress isn’t linear and flares can still occur along the way, patience and consistency matter more than any single week’s results. Regular follow-up with your doctor and nutritionist helps track real progress through symptoms and lab markers, rather than guesswork.

Can stress trigger autoimmune flares?

Yes — stress is one of the most consistently documented triggers for autoimmune flares, and this connection is now considered a core part of comprehensive care rather than a secondary lifestyle detail. Psychological stress raises cortisol, and while short bursts are anti-inflammatory, chronically elevated stress disrupts this regulation and instead promotes systemic inflammation. Stress also increases intestinal permeability, weakening the gut barrier and allowing more immune-triggering particles into circulation, and it shifts immune activity toward a more inflammatory profile. On top of that, stress can alter the gut microbiome, reducing beneficial bacteria that normally help keep inflammation in check. Many patients notice flares follow periods of major life stress — a job change, grief, illness, or poor sleep — even when their diet hasn’t changed. This is why stress-management techniques, such as sleep, movement, and therapy or mindfulness practices, deserve the same attention as diet in an autoimmune care plan. Discuss a personalized stress-management approach with your care team.

“Autoimmune diseases can feel overwhelming, but I always remind my patients: you have more agency than you think. Every meal is an opportunity to send anti-inflammatory signals to your body. Every lifestyle choice either supports or undermines your immune balance. That’s empowering.”

— Taissa Castello, PodIgest

Ready to Take the Next Step?

If you’re looking for specialized nutritional guidance, Taissa Castello offers teleconsultations via Google Meet for patients worldwide. Whether you’re in Brazil or abroad, you can get expert, personalized support for your gut health, autoimmune conditions, or food allergies.

Or visit our booking page for more options.

Medical Disclaimer

This article is for informational purposes only and does not replace individualized medical or nutritional advice. Always consult a qualified healthcare professional before making changes to your diet or treatment plan. Taissa Castello is a registered nutritionist (CRN-4 25106120) and does not prescribe medications.

References

• Fasano, A. (2012). Leaky gut and autoimmune diseases. Clinical Reviews in Allergy & Immunology, 42(1), 71-78.
• Abbott, R. D., Sadowski, A., & Alt, A. G. (2019). Efficacy of the Autoimmune Protocol Diet as Part of a Multi-disciplinary, Supported Lifestyle Intervention for Hashimoto’s Thyroiditis. Cureus, 11(4), e4556.
• Lerner, A., Jeremias, P., & Matthias, T. (2017). The world incidence and prevalence of autoimmune diseases is increasing. International Journal of Celiac Disease, 3(4), 151-155.

Read also: FODMAP Diet: Complete Guide | SIBO Symptoms Guide

Taissa Castello Fonseca

Nutricionista Clínica • CRN-4 25106120

Especializada em doença celíaca, SIBO, doenças autoimunes e saúde da mulher. Celíaca há 9 anos. Atende 100% online para todo o Brasil.

Sobre a Taissa Agendar consulta @taissacastello.nutri