How Food Sensitivities Influence Metabolism, Digestion, and Hormones

Fatigue that lingers. Focus that slips. Inflammation with no clear origin. These symptoms show up in exam rooms daily—and often persist despite normal labs, clean diets, and well-structured protocols. or many, the underlying trigger may look like a hormone imbalance or nutrient gap when the root cause is a hidden immune reaction to food.

Unlike classic food allergies that cause immediate responses—like hives or airway swelling—delayed reactions, often mediated by IgG antibodies, can quietly impact gut health, hormone clearance, neurotransmitter production, and energy metabolism. Over time, this creates a persistent immune burden and chronic inflammation that standard treatments may miss.

As Candice Coleman Pope, NP and founder of TheWholeNP, explained in a recent Access Live webinar, “Food is more than fuel—it’s immunologic input.” When the immune system misidentifies food as a threat, even clean eating can backfire. Without the right testing protocols, these patterns often remain invisible, leaving both patients and providers guessing.

Here's what you'll find in this article:

• Immune Response 101: A Brief Overview of Antibodies
• IgE & IgG: What Do They Measure?
• How IgE and IgG Responses Create Systemic Ripple Effects
• How to Use IgE and IgG Testing in Practice

Immune Response 101: A Brief Overview of Antibodies

The immune system produces different antibodies—also called immunoglobulins—that recognize and neutralize bacteria, viruses, allergens, and food antigens. Understanding their functions helps clinicians interpret test results and identify the true source of immune reactivity.

IgE & IgG: What Do They Measure?

Immune reactions to food don’t always follow the same script. Some are immediate and dramatic. Others are subtle and delayed—creating a low-grade inflammatory load over time. Understanding these two patterns helps clinicians interpret symptoms that otherwise seem disconnected.

IgE: The Fire Alarm

When someone reacts to a food within minutes—think hives, shortness of breath, or swelling—that’s an IgE-mediated allergy. These are acute, histamine-driven responses that typically require strict avoidance.

IgG: The Slow Burn

IgG responses are more delayed—showing up 24 to 72 hours after exposure. Symptoms may include fatigue, bloating, skin flare-ups, or mood changes. These aren’t traditional “allergies” but immune reactions that contribute to systemic burden over time.

“If the IGG panel lights up like a Christmas tree, I immediately evaluate the gut lining.”

- Candice Coleman-Pope, NP

View Complete foodANALYZER sample report. 

How IgE and IgG Responses Create Systemic Ripple Effects

Understanding the difference between IgE and IgG reactivity isn’t just academic—it’s actionable. Each response type has distinct effects on physiology, and when unaddressed, they can impact everything from hormone clearance to mental sharpness.

1. Gut Integrity & Immune Burden

IgG-mediated food sensitivities often coincide with increased intestinal permeability (“leaky gut”). When the gut lining is compromised, food proteins cross into the bloodstream activating the immune system and triggering widespread inflammation. This ongoing reactivity becomes both a cause and consequence of further mucosal damage.

2. Hormonal Disruption

Inflammation doesn’t stay isolated in the gut—it affects liver detox pathways, adrenal function, and hormone signaling:

• Estrogen Detox Impairment: Inflammatory stress can reduce hepatic estrogen clearance, contributing to PMS, bloating, and irregular cycles.
• Cortisol Dysregulation: Chronic immune activation stresses the HPA axis, leading to cortisol imbalances that worsen fatigue, anxiety, and weight retention.
• Thyroid Suppression: Cytokine-driven inflammation can lower active T3 or raise reverse T3, mimicking hypothyroid symptoms even when TSH appears normal.

3. Neurotransmitter Imbalance

Since the gut plays a major role in producing serotonin and dopamine, inflammation here can show up as mood swings, anxiety, lack of focus, or low motivation. These symptoms are often mislabeled as mental health issues when they may be rooted in gut-immune dysfunction.

“The gut produces 90% of serotonin and 50% of dopamine. If food triggers are inflaming the gut, they’re also impacting the brain.” 

- Candice Coleman-Pope, NP

4. Metabolic Impact

Both IgE and IgG responses can interfere with metabolic flexibility:

• Insulin Resistance: Chronic inflammation impairs insulin signaling, contributing to blood sugar instability and stubborn weight gain.
• Mitochondrial Disruption: Inflammatory mediators and oxidative stress interfere with ATP production, leaving patients fatigued even with adequate sleep and nutrition.

How to Use IgE and IgG Testing in Practice

Testing both IgE and IgG antibodies gives clinicians a broader perspective on immune activity and food reactivity. This dual approach helps to:

•    Prioritize food eliminations with higher clinical relevance
•    Target gut repair strategies more effectively. 
•    Support endocrine, metabolic, and cognitive recovery from the ground up

“I test, not guess. IgG antigens have a half-life of ~21 days. Without removing food for that long, you can’t be sure you're not reactive.”  

- Candice Coleman-Pope, NP

[Related Content] GLP-1 and Gut Health: Addressing Metabolic Dysfunction

IgG tests for food sensitivities, like Access Medical Labs' foodAnalyzer panel offer clear advantages for clinicians working with complex cases:

• Quantified signal intensity – so you can differentiate between mild and significant reactivity, helping to prioritize which foods to remove first.
• Broad antigen coverage – including not only common foods but also additives, gums, spices, and hidden triggers that often evade standard panels.
• Visual reporting tools – intuitive charts and gradations that help patients understand their immune responses and track improvements over time.

These tools are especially useful for patients with:

• Mood and cognitive symptoms that don’t align with mental health history
• Metabolic resistance that persists despite diet and exercise
• Hormonal imbalances tied to cycle irregularity, adrenal fatigue, or thyroid dysfunction
• Autoimmune presentations with unclear flare patterns

Whether you're refining an elimination protocol, supporting hormone clearance, or rebuilding gut-brain resilience, IgE and IgG testing provides the data needed to move from guesswork to clarity.

References:

• Coleman P. The Power of IgE and IgG Testing: Restoring Gut Health & Enhancing Metabolism. Access Live. 2025. Access Live: The Power of IgE & IgG Testing: Restoring Gut Health & Enhancing Metabolism
• Faria AMC, Gomes-Santos AC, Gonçalves JL, et al. Food components and the immune system: from tonic agents to allergens. Front Immunol. 2013. https://doi.org/10.3389/fimmu.2013.00102
• De Filippis F, Pellegrini N, Vannini L, et al. Diet-induced dysbiosis of the intestinal microbiota and the effects on immunity and disease. Nutrients. 2016. https://doi.org/10.3390/nu8010027
• Cryan JF, Dinan TG. Mind-altering microorganisms: the impact of the gut microbiota on brain and behaviour. Nat Rev Neurosci. 2012. https://doi.org/10.1038/nrn3346

About Access:

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