Red Meat Allergy? A Dive Into Alpha-Gal Syndrome

Red Meat Allergy? A Dive Into Alpha-Gal Syndrome

Published on Wednesday, November 22, 2023 by Emily Hamm

Alpha-Gal Syndrome (AGS): Unraveling the Mystery of Red Meat Allergy

A patient of mine recently told me, “All of a sudden, I don’t tolerate red meat,” when he had previously been eating it with tolerance. Interestingly, he had previously traveled and spent time outdoors in the wilderness- he didn’t recall any recent tick bites, but it left me thinking, could this be Alpha-gal syndrome?

The Tick Connection: How AGS Begins

Tick bite-borne illness is rising, specifically, this newer phenomenon called Alpha-Gal Syndrome (AGS), aka red meat allergy. With its recent discovery in 2007, it has increasingly become a problem, especially among the southeastern U.S., where certain ticks are prevalent. Worldwide, other cases are mentioned, and growing knowledge of AGS has led researchers to believe it may be more common than diagnosed.

The CDC’s estimate suggests that the U.S. had approximately 110,000 suspected cases of AGS from 2010 to 2022. However, the actual number of cases remains unknown due to reporting factors.

The Wide Spectrum of AGS Symptoms

AGS is interesting for several reasons, and there is still so much researchers do not understand about its manifestation within humans. It presents as a delayed allergic reaction to red meat. Some of the symptoms listed below you would think immediately occur since it is considered an IgE-mediated allergic reaction. However, with AGS, the majority of symptoms are delayed, and onset appears anywhere from 2-10 hours after ingestion of red meat. 

Some reactions may occur during the night while a person sleeps, including sudden awakening with GI pain and symptoms. Also, people living with AGS may not present with all symptoms due to sensitization. Many cases only present with GI symptoms, making it difficult to diagnose and differentiate from other functional GI disorders such as IBS and reflux. 

A majority of people who experience symptoms of AGS do not relate their symptoms initially to food. Recent research suggests that mast cell activation in coronary arteries may be linked to an increased risk of coronary artery disease in AGS. Let’s take a look at the common symptoms associated with alpha-gal syndrome.

Symptoms of AGS include:

  • Anaphylaxis (a serious allergic reaction that needs immediate medical attention)
  • Hives
  • Swelling
  • Diarrhea
  • Abdominal pain and cramping
  •  Nausea and vomiting
  • Reflux

Why Red Meat? The Alpha-Gal Connection

You may ask: WHY RED MEAT? Galactose-α-1,3-galactose (alpha-gal) is a disaccharide sugar found in fats and proteins in most mammals except for monkeys, apes, and humans. Alpha-gal is present in animal products that we commonly consume and a wide array of cosmetic, pharmaceutical, and other miscellaneous products.

With AGS, people are infected via a tick bite and receive alpha-gal antigens from the tick's saliva, initiating an IgE-mediated reaction upon interaction with alpha-gal from outside factors such as red meat.

Alpha-Gal Syndrome

 small observational study found that symptom improvement occurred 14 months after following a strict avoidance diet, and many were even able to re-introduce some foods after a period of elimination.

If you suspect that you may have AGS, it is essential to talk with a healthcare provider to discuss your symptoms and potential exposures to alpha-gal. If you will be outdoors, please wear appropriate clothing to limit exposure to tick bites and routinely check for bites after being outdoors. 

Ticks commonly bite in these places: hairline/scalp, behind and in ears, behind elbows, knees, armpits, groin, and waist. Look for bulls-eye-looking bites/rashes; this may indicate a tick bite. If diagnosed with AGS, work with a dietitian to discuss ways to incorporate appropriate sources of protein and fat in your diet to avoid malnutrition and potential deficiencies.

Living with AGS

Managing Your Diet with AGS

Foods to Avoid and Other Considerations:

-Mammalian meats- read meat, even sausage casings

- Caution with high-fat foods such as dairy and butter

-Avoidance of cofactors such as alcohol as this could enhance symptoms of AGS

-Caution with eating out: need to ask about the preparation of gravies, oils, sauces, and stocks

-If dairy is not tolerated, also beware of gelatin and carrageenan (emulsifier found in foods)

-Cross-contamination when cooking foods

Navigating Everyday Exposures:

-Pet dander MAY contain alpha-gal and could exacerbate reactions

-In severe cases, fumes from cooking meat have been reported as problematic for a small amount of cases

-Bee, wasp, and hornet stings, as well as repeated tick-bite exposure, could result in increased sensitivity to alpha-gal

Medications and AGS: What to Watch For:

-Heparin could be a possible exposure to alpha-gal

-Gelatin-based capsules, gelatin-containing vaccines, lactose, microcrystalline cellulose, and magnesium stearate may contain alpha-gal

-Erbitux (monoclonal antibody treatment)

Conclusion: Savoring Life with Alpha-Gal Syndrome

Alpha-Gal Syndrome, or red meat allergy, is a fascinating yet perplexing condition that continues to baffle medical experts. With its delayed allergic reactions and diverse symptoms, diagnosing AGS can be challenging. Nevertheless, increased awareness, meticulous tick-bite prevention, and dietary adjustments can help those affected lead fulfilling lives. 

If you suspect you have AGS, consult a healthcare provider for guidance on managing symptoms and exposures. Remember to work with a dietitian to navigate dietary changes. AGS may pose unique challenges, but with the right knowledge and support, you can make informed choices to savor a healthy and satisfying life.


  1. Alpha-gal syndrome | CDC. (2023, July 28). Centers for Disease Control and Prevention.
  2. Commins, S. P. (2020). Diagnosis & management of alpha-gal syndrome: lessons from 2,500 patients. Expert Review of Clinical Immunology, 16(7), 667–677.
  3. Croglio, M. P., Commins, S. P., & McGill, S. (2021). Isolated gastrointestinal alpha-gal meat allergy is a cause for gastrointestinal distress without anaphylaxis. Gastroenterology, 160(6), 2178-2180.e1.
  4. McGill, S., Hashash, J. G., & Platts‐Mills, T. A. (2023). AGA Clinical Practice Update on Alpha-Gal syndrome for the GI Clinician: Commentary. Clinical Gastroenterology and Hepatology, 21(4), 891–896.
  5. Sharma, S. R., & Karim, S. (2021). Tick Saliva and the Alpha-Gal syndrome: Finding a needle in a haystack. Frontiers in Cellular and Infection Microbiology, 11. 


Leave a comment on this article: