What is Alpha-Gal Syndrome?

Alpha-gal syndrome (AGS), often described as “red meat allergy”, is a food allergy characterized by a delayed - and potentially life threatening - reaction that can strike a person at any age.  It saw a surge in popularity and discussion somewhat recently, but just like many subjects that go viral in a short amount of time, misconceptions and story-driven slants are bound to crop up along the way.

Alpha-Gal Syndrome isn't new

When the condition was first described in 2009, the offending molecule, galactose-alpha-1,3-galactose (alpha-gal for short, hence the name), was only known to be found in the flesh of mammals (excluding some primates like humans) and a new intravenous cancer treatment (reactions to which lead to the discovery).  It was also assumed it took intravenous or large dietary exposures to trigger reactions.  Since then it has been found that people with the condition may also react to other mammal products such as gelatin, dairy, lanolin and derivatives, and that small trace amounts of cross contamination are enough to cause illness in sensitive patients.   To make matters worse, carrageenan, a vegan additive frequently used in nondairy substitutes, is reported to also cause reactions by many patients.  The diversity of products containing alpha-gal, combined with label laws that don’t yet require derived products to indicate what they were made from, make alpha-gal syndrome one of the most challenging allergies to live with. Unfortunately, while alpha-gal syndrome (AGS) likely existed in some form long before its discovery, it seems that it may also be increasing in frequency and severity in westernized countries in recent years.  The exact reasons for this are unclear, but the prevalence of mammal products in processed foods, the addition of carrageenan to the diet, and an increase in tick activity have all been speculated to play a role.  That’s right, alpha-gal syndrome is yet another tick induced ailment on what seems like an endlessly expanding list.  

What Causes Alpha-Gal Syndrome?

Many, but not all, people who develop the alpha-gal allergy report experiencing tick bites a few months prior to onset, yet AGS does not appear to be caused by an infectious agent like other tick borne ailments.  Instead, it is thought to be an immune response to the saliva of the tick.  Humans naturally have strong immune reactions to alpha-gal - this is why animal organ transplants can not safely be done on humans.   Normally, the human body suppresses the reaction and keeps it firmly limited to igG antibodies, but when a tick bites a human, the immune system suddenly starts producing igE antibodies.  These IgE responses are what cause allergic reactions.Until recently, only 3 species of ticks had been verified as causing the condition worldwide, but no species had been ruled out. New species are now being found, thanks to success with inducing alpha-gal syndrome in mouse models using tick saliva, but there are hundreds out there to be tested. That, of course, means that the most aggressive types are the ones first on the list to be checked.   There may also be other triggers and risk factors that haven't been discovered yet.  Scientist just don’t know enough about how the condition starts yet to be entirely sure.  What is known, is that once AGS has begun, the more bites a person gets, the more severe the condition gets.  In the worst cases, even cooking fumes can cause reactions when inhaled, much like the infamous peanut allergy.

What are the Symptoms of Alpha-Gal Syndrome?

The symptoms of alpha-gal syndrome can be deceptive.  Mild cases usually present sporadically 3-8 hours after exposure with some of the following:
  • Hives (urticaria)
  • Digestive distress 
  • Constipation that lasts for several days
  • Painful cramps
  • Bloating
  • Diarrhea
Many people will initially only react to high fat meats such as beef steak.  In more sensitive cases, reactions may appear after exposure to any mammal derived product, carrageenan or cross contamination.  Occasionally, people who have eaten mammal organ meat may have a reaction in under an hour. Other reaction symptoms can be any combination of those aforementioned along with rash, itching, swelling, joint pain or sudden drops in blood pressure.  Cardiac arrest due to low blood pressure is the largest concern for most patients, and since it may occur without the outward symptoms normally associated with anaphylaxis, people with alpha-gal syndrome are advised to not only carry an epipen, but to watch for signs of low blood pressure such as headache, dizziness, nausea, foggy headedness or momentary changes in vision upon standing.  

Diagnosing Alpha-Gal Syndrome

All too often alpha-gal syndrome is misdiagnosed as a variety of different maladies that carry some of the same trademark symptoms. The following are a variety of conditions that are, unfortunately, often pointed to as the cause of these troubles:
  • Irritable bowel syndrome
  • Orthostatic hypotension
  • Rheumatoid arthritis
  • Idiopathic urticaria
  • Gluten intolerance
Due to the variety of ailments that can cause similar symptoms, this list is far from definitive but is instead a collection of some of the most common scapegoats. With all that being said, alpha-gal syndrome is strange for a lot of reasons.  It doesn’t start the way other food allergies do, it is a carbohydrate rather than a protein, reactions don’t occur until an average of 3-8 hours after ingestion, and it only shows up on skin prick tests in the most sensitive individuals.  To deal with this, a specialized blood test was developed, yet even this test remains imperfect - especially for older cases. This leads allergists familiar with alpha-gal syndrome to focus heavily on case history to identify the condition thanks to its unique quirks. Right now, the best advice for avoiding the condition or preventing it from getting worse seems to be to avoid tick bites.  For those that have already developed the condition, symptoms can be eliminated by avoiding exposure to mammal products and carrageenan, which should become easier in the near future as awareness spreads and law makers and companies start to see value in labeling food and medicine more clearly.


  1. ALPHA GAL & Covid 19...Question for my Alpha-Gal friends...Has anyone got their Covid shot? Would like some input and thoughts from those who have AG and how they are dealing with C19?


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