Having a bad reaction to food can be a confusing and frustrating experience. You may feel fine one moment and then suddenly suffer from bloating, cramps, or even more severe symptoms the next, derailing all your plans. This leads many to avoid certain foods, often gluten and dairy which have been named as culprits for decades. When people feel better avoiding trigger foods, it reinforces the notion that they have either food sensitivities or allergies to those foods. Now this may be true for some people, but as immunologists and allergists correctly point out, the numbers do not add up.

According to a study published in JAMA Network Open, around 20% of Americans self-report having food sensitivities. This statistic includes individuals who might not have a clinically diagnosed condition but experience symptoms like bloating, inflammation, or fatigue after eating certain foods. Many of these individuals follow specific diets, such as gluten-free, based on their self-diagnosed sensitivities.

However, only about 6% of, or 19.2 million, Americans have a food allergy according to a Centers for Disease Control (CDC) 2023 National Center for Health Statistics review of two studies. The prevalence is slightly higher among black, non-Hispanic individuals, with 8.5% of adults and 7.6% of children reporting food allergies. Comparatively, white, non-Hispanic adults and children have food allergy rates of 6.2% and 5.3%, respectively. Hispanic populations have the lowest levels reporting food allergy rates of 4.4% for adults and 5% for children.

With 6% of the population suffering from food allergies, the remaining 14-20% of self-reported sufferers from undiagnosed digestive issues may or may not be suffering from food sensitivities. It turns out that small intestinal bacterial overgrowth (SIBO) causes similar GI distress symptoms. Understanding the differences can help get to the root cause of GI distress. With proper treatment, you can enjoy your meals again.

Understanding Food Sensitivities and Allergies

Food sensitivities and allergies are immune system responses to certain foods. They can range from mild to severe, with symptoms varying widely among individuals.

• Food Allergies involve an immediate reaction by the immune system and are typically IgE-mediated. Common symptoms include hives, swelling, difficulty breathing, and anaphylaxis in severe cases. These reactions are quick and often occur within minutes to hours after consuming the offending food.
• Food Sensitivities are generally less immediate and severe but can still significantly impact quality of life. They may involve IgG, IgG4 and complement 3 factors. Symptoms can include digestive issues like bloating, diarrhea, and constipation, as well as headaches, fatigue, and joint pain. Unlike allergies, sensitivities can take hours to days to manifest.

Testing for Food Sensitivities and Allergies

Diagnosing food sensitivities and allergies often involves various blood tests.

• IgE Testing is used to diagnose food allergies. High levels of IgE antibodies specific to certain foods indicate an allergic reaction.
• IgG4 Testing measures the presence of IgG4 antibodies against specific foods, helping to identify food sensitivities and IgE allergy tolerances.
• IgG Testing measures the presence of IgG antibodies against specific foods, helping to identify food sensitivities. IgG is made for both good and bad reasons. Therefore, it isn’t diagnostic on its own but can be used along with other testing or used to create a guided elimination diet.
• Complement 3 Factor Testing can be used in conjunction with IgG4 to provide a more comprehensive picture of food sensitivities. Complement 3 factor increases adverse reactions of IgG sensitivities.

These tests can provide valuable insights but should be interpreted by a healthcare professional to create a tailored treatment plan.

What is SIBO?

SIBO occurs when there is an abnormal increase in the number of bacteria in the small intestine. These bacteria can disrupt normal digestion and absorption, leading to a variety of symptoms, including:

• Bloating
• Gas
• Abdominal pain
• Diarrhea or constipation
• Malabsorption of nutrients

Testing for SIBO

SIBO is typically diagnosed through breath testing.

• Lactulose Breath Test involves ingesting a sugar solution and measuring hydrogen and methane levels in the breath over a few hours. Elevated levels indicate bacterial fermentation in the small intestine. Lactulose is not absorbed by humans, but they are an easy sugar for bacteria to consume. Lactulose breath testing assesses gas activity of both the small and large intestines.
• Glucose Breath Test works similarly, using glucose instead of lactulose. It’s another way to detect bacterial overgrowth based on the gases produced during digestion. Glucose absorbs quickly in the small intestines, with very little reaching the large intestines.

Differentiating Between Food Sensitivity and SIBO

While both food sensitivities and SIBO can cause digestive distress, there are key differences.

• Symptom Onset: Food sensitivity symptoms can take hours to days to appear while food allergies typically occur immediately or within minutes of consumption. SIBO symptoms often occur shortly after or within 2-3 hours of eating and can linger.
• Symptom Types: Food sensitivities can cause a wide range of symptoms including systemic issues like headaches and fatigue. SIBO primarily causes digestive symptoms although they too can contribute to systemic issues (headaches, rashes, etc.) which confuses clinic diagnosis.
• Diagnostic Tests: Blood tests can identify food sensitivities and allergies, whereas breath tests are used to diagnose SIBO. As a side-note: Finger-prick food sensitivity testing should be avoided due to reduced specificity and more false positives and negatives versus a more reliable blood draw test.

Managing Food Reactions

• Food Sensitivities: Avoiding trigger foods, working with a dietitian and healthcare provider, as well as using elimination diets can help manage symptoms. In some cases, supplements like digestive enzymes or probiotics may be beneficial.
• SIBO: Treatment typically involves antibiotics or herbal antimicrobials to reduce bacterial overgrowth, followed by dietary changes and probiotics to restore a healthy gut microbiome.

Understanding the root cause of your food reactions is the first step toward effective management and relief. Whether it’s a food sensitivity or an imbalance in your gut microbiome, proper diagnosis and treatment can help you reclaim your health and enjoy your meals without discomfort.

If you are a patient interested in testing with Neurovanna, ask your doctor to complete this referral form or contact us to find a doctor near you. If you are a healthcare provider interested in using breath testing to assess SIBO, set up a Neurovanna account.