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-borne illness is rising; specifically, a newer phenomenon called Alpha-Gal Syndrome (AGS), aka red meat allergy. Since its discovery in 2007, it has become a growing problem, especially in the southeastern U.S., where certain ticks are prevalent. Worldwide, other cases are reported, 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 researchers still do not understand much about how it manifests in humans. It presents as a delayed allergic reaction to red meat. Some of the symptoms listed below might seem like they should occur immediately, 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 at night while a person sleeps, including sudden awakening with GI pain and other 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.
- 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 through a tick bite and receive alpha-gal antigens from the tick's saliva, triggering an IgE-mediated reaction when they encounter alpha-gal from outside factors such as red meat.
A small observational study found that symptoms improved 14 months after following a strict avoidance diet, and many were able to reintroduce some foods after elimination.
If you suspect you may have AGS, talk with a healthcare provider about 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 bullseye-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 to avoid malnutrition and potential deficiencies.
Living with AGS
Managing Your Diet with AGS
Foods to Avoid and Other Considerations:
- Mammalian meats- red 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 in a small number 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. 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 enjoy a healthy, satisfying life.
FAQs
Can you suddenly develop an allergy to red meat?
Yes. Alpha-gal syndrome can develop after someone who previously tolerated mammalian meat becomes sensitized to alpha-gal, a sugar found in most mammals. In the United States, AGS is primarily associated with tick bites, particularly from the Lone Star tick.
How long after eating red meat do alpha-gal symptoms appear?
Unlike many food allergies that cause symptoms within minutes, alpha-gal reactions are often delayed. Symptoms may develop several hours after exposure, which can make it hard to identify the trigger and may even cause reactions at night.
Can alpha-gal syndrome cause only digestive symptoms?
Yes. Some people with alpha-gal syndrome experience gastrointestinal symptoms such as abdominal pain, diarrhea, nausea, vomiting, or reflux without developing more recognizable allergy symptoms such as hives. Because these symptoms overlap with other digestive conditions, AGS may sometimes be mistaken for IBS or another gastrointestinal disorder.
Do people with alpha-gal syndrome have to avoid all mammalian products?
Not necessarily. Trigger foods and products can vary considerably from person to person. Mammalian meat is a primary concern, while tolerance of dairy, gelatin, and other alpha-gal-containing products varies. People diagnosed with AGS should work with their healthcare team to determine which foods and other exposures to avoid while maintaining a nutritionally adequate diet.
References
1Sharma, 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, 680264. https://doi.org/10.3389/fcimb.2021.680264
2About alpha-gal syndrome | alpha-GAL syndrome | CDC. Centers for Disease Control and Prevention. (2026, January 5). https://www.cdc.gov/alpha-gal-syndrome/index.html
3Croglio, M. P., Commins, S. P., & McGill, S. K. (2021). Isolated Gastrointestinal Alpha-gal Meat Allergy Is a Cause for Gastrointestinal Distress Without Anaphylaxis. Gastroenterology, 160(6), 2178–2180.e1. https://doi.org/10.1053/j.gastro.2021.01.218
4McGill, S. K., 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 : the official clinical practice journal of the American Gastroenterological Association, 21(4), 891–896. https://doi.org/10.1016/j.cgh.2022.12.035
5Commins S. P. (2020). Diagnosis & management of alpha-gal syndrome: lessons from 2,500 patients. Expert review of clinical immunology, 16(7), 667–677. https://doi.org/10.1080/1744666X.2020.1782745
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Comments
Emily
05/14/2024 at 01:21 PM
Hi Nathan- I am sorry you’re having to deal with that; I know that it has to be very challenging to navigate this. I highly recommend finding a physician or practitioner in your area that specializes in Alpha-gal syndrome. You may need testing to confirm specific triggers for you and to give you clearer parameters on what would be good for you to eat. Consuming protein is important to help manage malnutrition. Maybe try a plant-based protein powder (Ca’Chava is a great brand) and mix it with a plant-based milk (Almond Malk is a great brand).
Nathan
05/13/2024 at 08:26 AM
I was born with celiac disease and contracted alpha gal from tick bite in Ozarks. I’m rapidly losing weight
and suffering acute malnutrition.
What can I eat or what supplement can i take to augment my nutrition that won’t near kill me every time I try it ?
Please keep in mind ,I am in Arkansas and the term Healthcare here Is an oxymoron. Thank you for your time and consideration in this matter.
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