What You Need To Know About Food Sensitivities and the Gut

Welcome to Healthy Gut Healthy Thyroid!

This is your weekly roundup of the BEST actionable steps for those people with thyroid and autoimmune thyroid conditions who want to restore their health…by healing their gut. Whether you have hyperthyroidism or Hashimoto’s you will benefit from the content in this newsletter.

In today's issue:

• Main Topic: What You Need To Know About Food Sensitivities and the Gut

• Podcast Review: Can a Gut Cleanse Really Help Graves’ Disease?

• Ask Dr. Eric: How do I know if my digestive symptoms are related to the gut or hormones?

What You Need To Know About Food Sensitivities and the Gut

Food sensitivities are incredibly common, and before we dive into how to detect them, it’s important to understand how food can play a role in triggering autoimmune conditions like Graves’ disease and Hashimoto’s. We’ll also clarify the differences between food sensitivities, food allergies, and food intolerances.

How Food Can Trigger Autoimmunity

Certain foods can increase inflammation and reduce regulatory T cells (Tregs), which are critical for keeping the immune system in check. A reduction in these Tregs can increase the risk of developing autoimmunity.

Some foods—like gluten—can also increase intestinal permeability, commonly referred to as a leaky gut. As I’ve discussed in previous newsletters, a leaky gut is one of the three components of the “triad of autoimmunity,” along with genetic predisposition and an environmental trigger.

What Is Oral Tolerance?

Oral tolerance refers to the immune system’s ability to tolerate dietary proteins without reacting to them. Tregs are responsible for helping us develop oral tolerance and for keeping the immune system from attacking beneficial commensal bacteria (those that live in harmony with us).

When Treg levels are low, oral tolerance can break down. This loss of tolerance can increase intestinal permeability and, ultimately, lead to food sensitivities.

Food Sensitivity vs. Food Allergy

Food allergies are typically IgE-mediated. These are the types of reactions that most people are familiar with—immediate, sometimes life-threatening responses. For example, someone with a peanut allergy may experience swelling or trouble breathing within seconds or minutes of exposure.

Common IgE-mediated food allergens include:

✅ Milk
✅ Eggs
✅ Peanuts
✅ Fish
✅ Wheat
✅ Soy
✅ Tree nuts
✅ Shellfish (especially in adults)

Food sensitivities involve IgG antibodies, which are found in all body fluids and respond to bacteria and viruses. These reactions are delayed and may take several hours or even days to cause symptoms—making them harder to pinpoint.

Symptoms may include fatigue, joint pain, skin issues, brain fog, or digestive discomfort. While not life-threatening like certain food allergies, food sensitivities can still significantly affect quality of life and contribute to chronic inflammation.

The Most Common Food Allergens

While it’s possible to develop a sensitivity to almost any food, the following are among the most common offenders:

✅ Gluten
✅ Dairy
✅ Corn
✅ Soy
✅ Eggs
✅ Shellfish
✅ Peanuts

Additional foods that can sometimes be problematic include:

• Beef
• Pork
• Coffee
• Tea
• Citrus fruits
• Chocolate

How to Detect Food Allergies and Sensitivities

IgE testing detects immediate allergic reactions. These can be tested through skin-prick testing, where allergens are introduced to the skin, and a reaction is observed. A raised wheal (bump) indicates a positive reaction. Serum IgE testing (via blood) is another option that some practitioners prefer for accuracy.

IgG testing is the most common testing method for delayed food sensitivities. Many companies offer this type of testing. However, keep in mind that:

✔️ False positives and false negatives are possible.

✔️ A leaky gut can lead to an increased number of sensitivities.

✔️ If your results show multiple sensitivities, that often signals loss of oral tolerance and gut inflammation, not necessarily that every food is a problem for life.

Elimination and Reintroduction Diet

The elimination diet is still one of the most effective and affordable methods to detect food sensitivities. I’ve used this in practice for many years with great success.

Examples of elimination diets include the AIP/Level 3 diet, which I cover in detail in my books The Hyperthyroid Healing Diet and Hashimoto’s Triggers. If this feels too restrictive, a Paleo-style elimination diet is a good alternative.

Most elimination diets recommend removing common allergens like gluten, dairy, and other foods for at least 3–4 weeks, then reintroducing one food at a time while monitoring for reactions.

How to Correct Food Sensitivities

Avoiding the offending food can help in the short term, but the main strategy to reverse food sensitivities is to heal the gut and restore oral tolerance.

While some practitioners recommend avoiding even “healthy” foods if they appear on a food sensitivity test, it’s important to understand the cause of the sensitivity. For example, if you show a sensitivity to broccoli, it's probably not the broccoli causing the problem—it's more likely due to increased gut permeability or immune dysfunction.

That said, taking a temporary break from the food while healing the gut can still be helpful.

An exception is gluten, which has been shown to directly increase intestinal permeability—even in those who don't feel symptomatic. So even if gluten doesn’t show up on a food sensitivity test, it’s often best to avoid it, especially when healing from thyroid autoimmunity.

What's a Food Intolerance?

Unlike food allergies or sensitivities, food intolerances don’t involve the immune system. They’re usually related to enzyme deficiencies (like lactose intolerance due to low lactase levels) or reactions to substances like histamine.

A histamine intolerance, for example, occurs when the body can’t properly break down histamine, leading to symptoms like headaches, hives, and digestive discomfort.

Final Thoughts

If you're struggling with food sensitivities or suspect that foods are playing a role in your symptoms, start with gut healing and oral tolerance restoration. Use testing when appropriate—but always interpret the results in the context of the whole picture. And remember, the goal isn’t to avoid more and more foods forever—it’s to heal your gut so you can enjoy a broader diet again.

Not All Gut Healing Supplements Are The Same

Since most of the immune cells are located in the gut, a healthy gut is essential for a healthy immune system. In fact, Hippocrates himself said that “all disease begins in the gut”. And so whether someone has Graves’ disease, Hashimoto’s thyroiditis, or another health condition, having a healthy gut is important to achieve optimal health.

When choosing a gut healing supplement you want one that does the following:

• Promotes optimal function of the GI lining

• Rejuvenates health of intestinal mucosa

• Supports healthy inflammatory response

• Builds immune support

• Thyroid-friendly ingredients

The Gut Healing Bundle includes the following:

SMT-GI Restore. Combines effective clinical levels of well-researched (and thyroid-friendly) nutrients and botanicals specifically formulated to support optimal gastrointestinal health and function without any added flavors, colors, sweeteners, gums or common allergens.

Enzymes Plus. Comprised of a proprietary blend of digestive enzymes along with betaine HCL and ox bile to support optimal digestion of proteins, fats, and carbohydrates. Also contains the special protease DPP IV (dipeptidyl peptidase IV), which aids in the breakdown of the peptides gluteomorphin (from gluten) and casomorphin (from casein). Although you don’t need to be experiencing digestive symptoms to use Enzymes Plus, it may be helpful for those who experience gas and bloating after eating, occasional constipation or diarrhea, or a feeling of fullness after eating.

SMT-Probio. Choosing a good quality and effective probiotic can be a challenge, as there are so many probiotic supplements on the market. Unfortunately many probiotic supplements only list the species, and not the specific strains. Others list the strains but aren’t diverse or potent enough. SMT-Probio Complete provide 18 different strains belonging to 13 different species of three different genera. For consumer convenience, this formula is available encapsulated at a maintenance dose of 45 billion CFUs per capsule. The HOWARU and FloraFIT strains that comprise these formulas are stable, proven, and trusted worldwide.

To learn more about The Gut Healing Bundle visit www.savemythyroid.com/GutHealing 

Save My Thyroid Podcast Review

I have a podcast called "Save My Thyroid", where I discuss how people with hyperthyroidism and Hashimoto's can save their thyroid and regain their health. And during each edition of this newsletter I'll briefly discuss a recent podcast episode.

In a recent podcast episode I discussed whether a “gut cleanse” can help those with Graves’ disease. Gut cleanses, detoxes, and parasite protocols are often positioned as the missing piece for autoimmune thyroid conditions, but the results don’t always match the promise.

This episode breaks down what people really mean when they say “gut cleanse,” where these approaches can be helpful, and why focusing only on clearing things out can leave the immune system stuck in high gear. It also explores how medications, detox pathways, gut repair, and nervous system balance intersect, and why timing and sequence matter more than doing “more.”

If you’ve tried cleanses hoping they’d finally calm your symptoms, this will help you understand what may be holding you back and how to approach gut health with more clarity and confidence. Tune in before you try another cleanse.

Ask Dr. Eric

During every issue I'll answer a question or two that I think can benefit most people with a thyroid or autoimmune thyroid condition. If you'd like for me to consider your question for a future edition of this newsletter email your question to [email protected].

QUESTION: HOW DO I KNOW IF MY DIGESTIVE SYMPTOMS ARE RELATED TO THE GUT OR HORMONES?

Dr. Eric, I've been experiencing a lot of bloating lately, but it's not consistent, and I can't pinpoint any foods. Is this a sign that it might be related to the hormones and not the gut?

Thanks for your question! Whenever someone experiences digestive symptoms, I believe it’s wise to rule out food-related causes first. One option is to try an elimination diet to see if symptoms improve.

That said, keep in mind that certain gut conditions don’t always cause symptoms with every meal. For example, someone with small intestinal bacterial overgrowth (SIBO) may only experience bloating when eating higher-FODMAP foods (such as fermented foods or certain high-fiber carbohydrates). In those cases, the bloating may seem inconsistent because it depends on what was eaten.

Another possibility is histamine intolerance. This can lead to digestive symptoms after consuming high-histamine foods such as fermented foods or alcohol. Again, the reaction may appear inconsistent if you’re not regularly consuming those foods.

In general, when digestive symptoms are directly related to food or the gut, they tend to appear within minutes to a few hours after eating. While it’s true that some food sensitivities can cause delayed reactions—sometimes even a day or two later—most digestive symptoms occur relatively soon after a triggering meal.

That said, hormonal fluctuations can absolutely contribute to bloating and other digestive symptoms. Changes in estrogen and progesterone can influence gut motility, fluid retention, and even sensitivity to certain foods.

If you’re perimenopausal, it can be more challenging to determine whether bloating is hormonally driven because hormone levels may fluctuate unpredictably. However, if you’re unable to connect your symptoms to specific foods, hormones become a more likely contributor.

For women who are still cycling regularly, timing can provide helpful clues. If you consistently experience bloating around ovulation or in the few days before your period, this strongly suggests a hormonal component. You may also notice other symptoms during those times, such as mood changes, fatigue, breast tenderness, or mild fluid retention.

Additional Thyroid-Related Resources

Click Here for Can a Gut Cleanse Really Help Graves’ Disease? (episode 229)

Click Here to access hundreds of thyroid-related articles and blog posts

Click Here to join the Graves’ disease and Hashimoto’s community

Click Here to purchase one of Dr. Eric’s thyroid-related books

Click Here to work with Dr. Eric and his team

That’s a wrap