Alpha-Gal

What is Alpha-Gal?

Galactose-alpha-1,3-galactose, more commonly known as alpha-gal, is a sugar found in mammalian or red meat (e.g., beef, pork, venison, goat, bison lamb, mutton) but not in human tissues. Allergy to the alpha-gal sugar has been associated with bites from the lone star tick.

The lone star tick, named for a central white mark on its back, is primarily found in the southern and central regions of the United States., but has been expanding its range. As a result, alpha-gal allergy is becoming increasingly prevalent.[1]

How Does a Tick Bite Result in an Allergy to Alpha-Gal?

The lone star tick feeds on animals whose meats contain alpha-gal. When the tick then bites a human, it injects alpha-gal from prior animal meals into the skin, which can sensitize the person to the sugar.

How Does Alpha-Gal Allergy Compare to Other Food Allergies?

Most food allergies are triggered by food proteins, but in the case of red meat allergy, the allergen is a sugar. Additionally, anaphylactic or severe allergic reactions to alpha-gal are often delayed, with symptoms developing three to six hours after eating.

The risk of developing allergy to red meat is influenced by genetic and environmental factors. However, the primary environmental factor for red meat allergy is not eating meat but being bitten by the lone star tick. Other research suggests that certain human blood types may also play a role in sensitivity to alpha-gal.[2]

If You Suspect an Allergy to Alpha-Gal

Suspected food allergies should always be evaluated, diagnosed, and treated by a qualified medical professional, such as a board-certified allergist. Your primary care provider can refer you to an allergist.

If You Have a Diagnosed Allergy to Alpha-Gal

Allergy to alpha-gal, like other food allergies, requires careful avoidance of the problem food and planning to be prepared for allergic emergencies. This includes carrying an epinephrine auto-injector, filling out a Food Allergy & Anaphylaxis Emergency Care Plan, and wearing medical identification.

  1. read food labels and ask questions about ingredients before eating a food that you have not prepared yourself. Red meat is not covered by the Food Allergen Labeling and Consumer Protection Act (FALCPA) and therefore won’t be declared as an allergen on the label. Consumers can call the manufacturer directly to inquire about ingredients and manufacturing practices.

Additional Resources

Podcast: Alpha-Gal Allergy with Dr. Scott Commins

 


[1]The Changing Face of Anaphylaxis. Fadahunsi, Angela et al. Journal of Allergy and Clinical Immunology ,

Volume 141 , Issue 2 , AB151

[2]B Antigen Protects Against the Development of α-Gal-mediated Red Meat Allergy
Brestoff, Jonathan R. et al. Journal of Allergy and Clinical Immunology , Volume 141 , Issue 2 , AB230