Secretory IgA: The Special Forces of the Gut-Immune System
If you’ve just received your lab results and want to understand your Secretory IgA levels, you’ve come to the right place.
In this post we’ll explore:
What is Secretory IgA?
What role does Secretory IgA play in the body?
How to interpret Secretory IgA levels.
What is Secretory IgA?
Secretory Immunoglobulin A, or SIgA, is a critical biomarker that helps professionals measure mucosal barrier health and immune system function in the mucous membranes of the gastrointestinal and respiratory tracts. As the most abundant antibody class found in mucosal barriers, SIgA plays a pivotal role in immune defense and homeostasis.
SIgA belongs to the immunoglobulin family, comprising nearly two-thirds of the body’s total immunoglobulin and acting as a specialized antibody in the adaptive immune system. The adaptive immune system acts like a special forces unit that is called in to protect the body from a current infection and destroy invading antigens and pathogens. Unlike antibodies found in the blood, SIgA is secreted into the gastrointestinal (GI) tract, where it plays a crucial role in maintaining mucosal barrier function.
SIgA is very responsive to stress. In the face of acute stressors, SIgA may increase in an attempt to combat potential infections. However, when this stress becomes prolonged and chronic, it can lead to a subsequent drop in SIgA levels, rendering an individual susceptible to various conditions. If you’ve ever gotten sick after a few stressful months, this can be partly due to chronic stress driving down SIgA levels and leaving your immune system in an even more weakened state.
What is Secretory IgA’s role in the gut?
Neutralizes antigens and pathogens: SIgA binds to antigens and pathogens. The complexes that SIgA forms with gut pathogens prevent them from adhering to the epithelial cells of the gut’s lining and the gut. This protective mechanism prevents them from crossing the mucosal barrier and triggering inflammatory responses.
Maintains mucosal barrier integrity: SIgA interacts with mucus and tight junctions of the gut lining, strengthening this physical barrier against pathogens and allergens. Tight junctions are like gatekeepers along the gut lining, controlling the flow of essential nutrients from your gut to your bloodstream. When compromised, tight junctions will remain open, allowing antigens and pathogens to flow into the bloodstream. SIgA plays a key role in keeping these tight junctions strong and preventing leaky gut and the associated systemic inflammation.
Balances the gut microbiome: SIgA selectively interacts with gut bacteria, promoting the growth of beneficial bacteria and suppressing the growth of pathogenic strains. This fosters a balanced and healthy microbial environment. When this microbial balance becomes unbalanced, you’ll often experience unwanted symptoms such as bloating, diarrhea, constipation, stomach pain, food sensitivities, acid reflux, and poor digestion.
What do Secretory IgA lab values mean?
When looking at lab values, context is important. Traditional lab value ranges reflect the average health of the population, which is trending downward. So even if you fall within “normal” range, that doesn't mean your levels are optimal. We recommend taking a holistic perspective and considering your age, gender, lifestyle, and stressors to contextualize values and identify what an optimal level would be for you.
High SIgA levels (above 2010 ug/g)
High levels are linked to immune system activation triggered by acute and chronic infections, pathogens, stress, and exposure to environmental toxins, food allergies, and sensitivities. As discussed above, SIgA acts like a special forces unit, neutralizing assaults on the gut’s immune system. When these assaults are constant, SIgA levels may eventually decline, leaving an individual immunocompromised.
One more thing on food sensitivities — these are no joke. They can be hard to identify and symptoms may appear unrelated to consumption. That’s why we recommend running a Mediator Release Test (MRT) to identify foods that cause internal inflammation and aren’t picked up by normal allergy tests.
Low SIgA levels (below 510 ug/g)
Low levels are associated with high or chronic stress. This can be induced by various factors, including mental/emotional stress, physical stress, or exposure to certain chemicals. Chronic infections, celiac disease, and inflammatory bowel disease (IBS), can also suppress SIgA, which fosters an environment where other infections can arise. While combating the primary infection or disease, your immune system may become overburdened and your gut lining will become more permeable. Given that 70% of your immune system is in your gut, this state of dysbiosis or “leaky gut” leads to increased food sensitivities, susceptibility to illness, risk of autoimmune disease, and overall decline in health.
Equivocal SIgA levels
Equivocal levels may be considered low depending on the client's presentation and other lab data. Poor diet, some drugs, viruses, impaired immune function, and chronic stress should always be considered when interpreting SIgA levels, providing a comprehensive understanding of the factors influencing immune health.
In Summary…
Secretory IgA plays a crucial role in maintaining mucosal barrier integrity and regulating immune responses in the gut and lungs. Measuring SIgA levels is a valuable clinical tool for assessing mucosal health, immune function, and potential vulnerabilities to various diseases.
If you’re unsure about your SIgA levels and have questions or concerns, book a discovery call with Wholistic Renewal. We’ll discuss your lab results and create a custom plan that heals your gut through a holistic, root-cause approach.
Fed up with unanswered questions about your health?
At Wholistic Renewal, we dig deep to uncover the root causes of your concerns. Our programs combine comprehensive functional lab testing with personalized protocols and dedicated support from a nutritional practitioner. Through one-on-one guidance and education, you can finally find the answers you've been searching for and renew your health.
*The information provided above is intended for educational purposes only and should not be construed as medical advice. Always consult with a qualified healthcare professional regarding any medical or health-related questions or concerns you may have. Reliance on any information provided in this blog is solely at your own risk.
