photograph from CDC
by Reed Mangels, PhD, RD
In america, from 2010 to 2022, 110,000 instances of alpha-gal syndrome had been reported (1). It’s doubtless that many extra instances went undiagnosed or unreported. Alpha-gal syndrome is a critical, probably life-threatening allergy to a substance known as alpha-gal. This allergy can develop after a tick chew. In america, the Lone Star tick is most frequently the sort of tick whose chew results in alpha-gal syndrome. In components of the South, folks speak about getting “chigger” bites. “Chiggers,” as they’re known as are sometimes the larva of Lone Star ticks and may introduce alpha-gal in the identical means that mature ticks do (2}. Right now, alpha-gal syndrome is most regularly identified within the southern, central, and japanese components of america (within the space bounded by New York, Iowa, Texas, and Florida), however instances have been reported from different components of america and in different nations (1,3).
Alpha-gal, formally often called galactose-α-1,3-galactose, is a sugar molecule. It’s present in most mammals however not in people. It is usually present in within the saliva of some ticks. When these ticks chew an individual, their saliva can introduce the alpha-gal into the particular person’s blood. The particular person’s physique then produces antibodies to the alpha-gal. Then, in some folks, once they eat mammals (like cows, pigs, deer, goats) or meals or different substances derived from these mammals (like milk, cheese, or ice cream or sure meals components or medicines) these folks’s our bodies react with the alpha-gal which is of course discovered on mammalian cells. This will result in an allergic response, generally inside 2 to six hours after consuming the meat or dairy product.
Vegans can have alpha-gal syndrome because of a tick chew. Though vegans wouldn’t eat meat or dairy merchandise, they may have an allergic response to meals that include meat or dairy or to components derived from mammals that they aren’t conscious are usually not vegan. Probably, a vegan burger cooked on the identical grill as a meat burger with out the grill being well-cleaned might trigger a response. Some sufferers have reported reactions from inhaling alpha-gal from bacon being fried or beef merchandise being grilled (3,4).
The one therapy for alpha-gal syndrome is to keep away from meat and different merchandise from mammals that set off reactions. These reactions might embrace bother respiration, dizziness, hives, swelling of the lips/tongue/throat/eyelids, nausea, vomiting, stomach ache, diarrhea, or decreased blood strain (1). A critical allergic response must handled as a medical emergency (5). One demise has been reported because of alpha-gal syndrome (2).
Some folks with alpha-gal syndrome select to eat a vegan food regimen, regardless that rooster, eggs, and fish don’t trigger an allergic response. They clarify that it’s easier to eat a vegan food regimen because of considerations about cross-contamination (6). Cautious label studying is vital for everybody with alpha-gal syndrome as a result of meals components like animal-derived gelatin, meat broth, beef tallow, and lard have the potential to trigger reactions. Carrageenan (a substance extracted from sea weeds and used as a meals thickener and stabilizer; additionally present in merchandise like toothpaste), though not a mammalian product, could cause reactions in a small quantity (estimated 1-2%) of individuals with alpha-gal syndrome (7,8). You’ll be able to learn extra about figuring out elements in treatment within the VRG weblog submit on magnesium stearate.
References
- Mollah F, Zacharek MA, Benjamin MR. What Is Alpha-Gal Syndrome? JAMA. 2024;331:86.
- Platts-Mills TAE, Workman LJ, Richards NE, et al. Implications of a deadly anaphylactic response occurring 4 hours after consuming beef in a younger man with IgE antibodies to galactose-α-1,3-galactose. J Allergy Clin Immunol Pract. 2025;13:3422-3424.
- McGill SK, Hashash JG, Platts-Mills TA. AGA Medical Follow Replace on Alpha-Gal Syndrome for the GI Clinician: Commentary. Clin Gastroenterol Hepatol. 2023;21:891-896.
- American Academy of Allergy, Bronchial asthma, and Immunology. Alpha-gal and Crimson Meat Allergy. https://www.aaaai.org/tools-for-the-public/conditions-library/allergic reactions/alpha-gal-and-red-meat-allergy. 2025.
- Mayo Clinic. Alpha-gal Syndrome. https://www.mayoclinic.org/diseases-conditions/alpha-gal-syndrome/symptoms-causes/syc-20428608. 2025.
- Sempa J, Brenes P, Tegeler A, et al. Alpha-Gal syndrome within the heartland: Dietary restrictions, public consciousness, and systemic boundaries in rural Kansas. Vitamins. 2025;17:3043.
- Commins SP. Prognosis & administration of alpha-gal syndrome: classes from 2,500 sufferers. Knowledgeable Rev Clin Immunol. 2020;16:667-677.
- Wilson JM, Erickson L, Levin M, et al. Tick bites, IgE to galactose-alpha-1,3-galactose and urticarial or anaphylactic reactions to mammalian meat: The alpha-gal syndrome. Allergy. 2024;79:1440-1454.
To learn extra about alpha-gal syndrome see:
Journal of the American Medical Affiliation Affected person Web page: What’s Alpha-Gal Syndrome?
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