What is αS1-casein & αS2-casein and Why Does the Food Zoomer Test for It?

Milk casein structural proteins

αS1-casein and αS2-casein are two major milk casein proteins that help form the casein micelle and deliver amino acids and calcium. Measuring immune responses (IgA and IgG) to these proteins helps reveal how the body interacts with dairy at both mucosal and systemic levels, offering insight into food-related immune patterns.

View Food Zoomer

αS1-casein & αS2-casein

Quality and Security

High-quality testing run in a CLIA-certified and CAP-accredited lab in Santa Clara, California.

fortified-health-HIPAA-compliance-pqgjtx4popoe2n0arp68hrz8h2as5rlhgng5b2srk8 1

About αS1-casein & αS2-casein

${ activeTab.tab_content.text }

View ${ activeTab.tab_content.btn_label }

About αS1-casein & αS2-casein

Overview and History

αS1-casein and αS2-casein are phosphorylated milk proteins in the casein family, encoded by the CSN1S1 and CSN1S2 genes in bovines. Biochemically they are major components of the casein micelle, contributing to milk’s structure, calcium binding, and nutrient delivery to neonates. These alpha-caseins have been studied in food science and immunology for decades because they are common targets of antibody recognition. Their biochemical roles are nutritional and structural, while their antigenic properties make them useful markers when assessing immune responses to dairy proteins in clinical and research settings.

Interpreting Highs and Lows

Elevated antibody levels to αS1- and αS2-casein may indicate increased immune recognition of these dairy proteins. In the Food Zoomer context, higher IgA suggests stronger mucosal or gut-associated activity, while higher IgG suggests broader systemic immune memory or exposure. Low or undetectable antibody levels generally suggest little immune reactivity, recent avoidance of the food, or limited exposure. All results gain meaning when interpreted alongside other panel markers, symptom patterns, and exposure history.

Featured Test

These casein fractions are included to evaluate dairy-specific protein reactivity at the peptide level and to distinguish mucosal (IgA) versus systemic (IgG) patterns. Identifying casein-directed immune activity helps providers see whether immune responses cluster in the dairy domain, supporting targeted dietary planning and stepwise reintroduction approaches.

View Food Zoomer

αS1-casein & αS2-casein FAQs

What is αS1-casein & αS2-casein and why is it important?

αS1- and αS2-casein are two common milk proteins that contribute to milk structure and nutrition. The immune system can form antibodies against these proteins, so measuring them helps show whether dairy proteins are part of a person’s immune pattern. That information can be useful when exploring food-related symptoms and dietary choices.

What does it mean if my αS1-casein & αS2-casein levels are low?

Low antibody levels to these caseins usually mean little detectable immune response to those dairy proteins. This can reflect tolerance, limited recent exposure, or that other foods are driving symptoms. Low results should be interpreted with the rest of the Food Zoomer panel and your dietary history.

What does it mean if my αS1-casein & αS2-casein levels are high?

Higher antibody levels indicate immune recognition of αS1- or αS2-casein. An IgA-predominant pattern points toward mucosal or gut-linked activity, while IgG suggests systemic immune memory or exposure. Elevated results are a signal for further clinical interpretation alongside other markers and symptom patterns.

Why is αS1-casein & αS2-casein included in the Food Zoomer?

These casein markers help map dairy-specific immune responses within the panel’s dairy peptide domain. Measuring them at peptide-level and across IgA/IgG isotypes improves detection of localized versus systemic patterns, aiding providers in creating more precise dietary plans and reintroduction strategies.

Browse Articles

Gluten and Autoimmunity: What Celiac Clues Might Be Hiding

Gluten, a protein found in wheat, barley, rye, and related grains, is a staple in many diets worldwide. And for many individuals, it’s harmless to con...

Nancy Guberti, M.S., C.N.

Jul 2, 2025

Autoimmunity Food Reactions

Food Sensitivity vs. Allergies: What's the Difference?

Food Sensitivities vs. Allergies: Understanding the Difference with Advanced Testing

Many patients struggle with chronic symptoms like bloating, fatigue, and migraines but don’t get clear answers from standard allergy tests. As a healt...

Melissa Brescia

Mar 31, 2025

Food Reactions

Vibrant Research Spotlight: Food Sensitivity Clinical Trial

Food sensitivities can significantly impact health, causing symptoms like gastrointestinal distress, skin issues, and fatigue. Diagnosing and treating...

Jamie Haleva

Jul 29, 2024

Food Reactions Research & Innovation

The Link Between Diet and Disease: Insights from Food Sensitivity Testing

The diet and disease relationship is well established and has gained significant attention in the face of chronic ailments that may be rooted in poor ...

Jamie Haleva

Jul 15, 2024

Autoimmunity Food Reactions Longevity

About Vibrant:

The Experts Behind  Every Test

Our team is built on collaboration across disciplines to advance the science of wellness and longevity. At Vibrant Wellness, lab scientists, technologists, clinical researchers, doctors, practitioners, longevity advisors, engineers, and regulatory experts work side by side to transform diagnostics.

By uniting diverse expertise under one mission, we pioneer precision testing that empowers providers to uncover root causes, personalize care plans, and optimize patient health outcomes. Every test we develop reflects this commitment—to push boundaries in functional medicine, deliver clear, actionable insights, and support clinicians in helping patients live healthier, longer lives.

View All Tests

Results trusted by over 18,000 functional wellness professionals

We’re the leading provider of specialty wellness lab testing because we develop our testing with rigorous, ongoing research by top clinical experts, doctors, and scientists.

The gold standard of accuracy in  the lab industry

Our tests run on a proprietary 3Dense microchip technology platform that boasts unrivaled specificity and sensitivity. While most other labs carry only CLIA certification, we're CAP-accredited by the College of American Pathologists.

Our Clinical Support Team

We understand that patient care doesn't end with diagnosis. To achieve Vibrant health, patients need clinical support and
obtainable lifestyle changes. Our clinical support team helps providers make informed treatment recommendations, resulting in  better patient outcomes.

Mary Beth Augustine

DCN, RDN, FAND- Lead Clinical Educator

Suzanne Barker

MS, RDN, LD, CTTS, CGP- Clinical Educator

Suzette Garcia

MSc- MHNE- Clinical Educator

Brooke Mader Ganev

MS, CNS, LDN, FDN- Clinical Educator

Adair Anderson

MS, RDN, LDN- Clinical Educator

Lillie Luu Nguyen

DCN, CNS, LDN- Clinical Educator

Jason Barker

ND- Clinical Educator

Emaline Brown

ND- Clinical Educator

Dana Filatova

DCN, CNS, LDN- Clinical Educator

Jessy Dhanjal

ND- Clinical Educator

Nour Amri

MS, LDN, CNS, CKNS- Clinical Educator

Ready to Elevate Your Approach to Precision Wellness?

At Vibrant Wellness, we’re redefining the future of diagnostics—making complex science clear, accessible, and actionable. Whether you're a provider advancing personalized care or a patient seeking data-driven answers, our precision testing gives you the clarity to make informed decisions. Experience the next generation of functional medicine through clinically validated insights and seamless testing solutions.

Become a Provider

Become a Patient