April 5, 2024

What is alpha-gal syndrome (AGS)?

Alpha-gal syndrome (AGS) is a serious, potentially life-threatening allergic condition. AGS is also called alpha-gal allergy, red meat allergy, or tick bite meat allergy. AGS is not caused by an infection. AGS symptoms occur after people eat red meat or are exposed to other products containing alpha-gal.

What is alpha-gal?

  • Alpha-gal (galactose-α-1,3-galactose) is a sugar molecule found in most mammals.
  • Alpha-gal is not found in fish, reptiles, birds, or people.
  • Alpha-gal can be found in meat (pork, beef, rabbit, lamb, venison, etc.) and products made from mammals (including gelatin, cow’s milk, and milk products).


Alpha-gal syndrome or alpha-gal allergy, also referred to as Mammalian Meat Allergy (MMA), is a kind of meat allergy that manifests symptoms 3–8 hours after consuming mammalian meat. The illness is the consequence of previous tick bite exposure. American medical researchers and independent Australian researchers published the first reports of it in 2002, which makes it a fairly new syndrome.

A CDC report indicated that between 2010 and 2022, more than 110,000 suspected cases of AGS were identified. However, cases of AGS are not nationally notifiable to CDC, so it is not known how many cases of AGS exist in the United States. Additional data and research are needed to understand how many people are affected by this condition.

All animals, with the exception of humans, apes and Old-World monkeys, contain the alpha-gal molecule that causes this allergy. This carbohydrate can be transmitted to a victim by tick bites from particular tick species, such as the paralysis tick in Australia and the Lone Star tick in the US. This delayed allergic reaction to eating mammalian meat products, also known as “red meat,” results from the bite.

An allergic reaction to alpha-gal can cause rash, hives, nausea or vomiting, dyspnea, low blood pressure, lightheadedness, excruciating stomach pain, and anaphylaxis (a potentially life-threatening reaction involving multiple organ systems) and may need urgent medical care. To avoid causing an allergic reaction, food products including beef, pork, lamb, venison, rabbit, and organ meat are advised by medical providers to be avoided entirely. Some people with alpha-gal allergy are so hypersensitive that dairy products and some types of mammalian gelatin can cause a cross-reaction. However, since alpha-gal is not naturally present in reptile meats, poultry, or shellfish, those who are impacted do not need to follow a strict vegetarian diet. In other words, feather and fin are safe to consume.

This fascinating allergy has been documented in 17 nations across all six continents, with the United States and Australia being the countries where people are most likely to be bitten by ticks. Australia has the highest rate of tick anaphylaxis and mammalian meat allergy worldwide as of November 2019. The central and southern parts of the US are where the allergy is most common, which coincides with the Lone Star tick’s range. The real number of affected people is still unknown because of underreporting; however, awareness of alpha-gal syndrome is rising. This kind of food allergy known as “alpha-gal syndrome,” or simply “alpha-gal,” is brought on by a carbohydrate molecule termed galactose-alpha-1, 3-galactose. There are many symptoms that this allergy can induce, from moderate to severe, following the consumption of venison, lamb, pork, or beef. It is mostly linked to bites by Amblyomma americanum, or lone star ticks, which can expose humans to alpha-gal chemicals through their saliva as they feed.

Unlike most food allergies, which often show symptoms quickly after ingestion, alpha-gal syndrome is characterized by symptoms that usually appear many hours after consuming red meat.

It is still unclear exactly why some people who are bitten by lone star ticks develop alpha-gal syndrome. On the other hand, it is thought to be related to the body’s immune system producing IgE antibodies against the tick-transmitted alpha-gal molecules.

The goal of managing alpha-gal syndrome is to stay away from red meat and items made with derivatives of red meat.  People who have this sensitivity should also exercise caution while consuming certain drugs and gelatin-containing items as they could also be additional sources of alpha-gal.  It is critical for people with alpha-gal syndrome to collaborate closely with medical professionals to create a suitable management strategy and to be ready to handle any allergic responses that might arise.

If you think you may have AGS, go talk to your healthcare provider.  This allergy is initially caused by a tick bite. Since the reaction to eating mammal meat is delayed by several hours, the proper diagnosis is often missed or misdiagnosed.  People who are afflicted with the Alpha-Gal allergy have to be constantly vigilant about the ingredients they consume because an allergic reaction can be severe and life-threatening.

When a Lone Star tick bites a person, it transfers alpha-gal into the bloodstream. As a result, the person’s body produces antibodies to fight the sugar.  The next time that person eats meat from a mammal the meat triggers the release of histamine, a compound found in the body that causes allergic symptoms like hives, itching, stomach cramps, and in severe cases anaphylaxis. Fish, turkey and chicken are not mammals, so they don’t have alpha-gal.

AGS is diagnosed by an allergist or other healthcare provider through a detailed patient history, physical examination, and a blood test that looks for specific antibodies (proteins made by your immune system) to alpha-gal.

Depending on your sensitivity and the severity of your allergic reaction, your healthcare provider may also suggest you avoid other foods and ingredients which may contain alpha-gal, such as cow’s milk, milk-products and gelatin.

Read food product labels carefully.

Although very rare, some people with severe AGS may react to ingredients in certain vaccines or medications.  Talk to your healthcare provider before taking a new medication or receiving a vaccine.

I recently spoke to a friend who has Alpha Gal syndrome and asked two main questions for my research, ‘What is the worst thing about having Alpha Gal’; and second, ‘What is the best?’ Asking someone who has lived with this allergy for several years, his insight was thoughtful and informative.  The answer to the first question, what is the worst, his response is that alpha gal is life changing, everything you eat or touch must be considered. He indicated that he can have a reaction from shaking the hand of someone who just touched meat. All labels must be read carefully and eating out is nearly impossible due to the fact red meat is cooked in the same skillet as his meal is potentially cooked.  It is safer for him to eat at home.  The second question, what is best, his response is that he now eats much healthier, fin and feathers and vegetables. But even then, if the store-bought chicken or fish was processed at a factory with mammalian meat then he could possibly have an allergic reaction. Like those with nut allergies, he must constantly be on guard. However, food manufacturers do not indicate alpha-gal may be contained in any products.


Preventing tick bites is important and may reduce your chances of developing AGS.

  • Before you go outdoors
  • After you come indoors
    • Check your clothing for ticks.
    • Examine gear and pets for ticks.
    • Shower and perform a thorough tick check.
    • Thoroughly check children. Ask your spouse or partner to check you as well.
  • If you see an attached tick,  remove it immediately and kill it.
  • Wash the area thoroughly and wash your hands if you touched it.
  • Take steps to prevent ticks on your pets and in your yard.
  •  Put your pets on flea and tick control.