ALPHA-GAL SYNDROME: A TICK-TRANSMITTED RED MEAT ALLERGY EVERYONE SHOULD KNOW ABOUT

Medically Reviewed by Dr. Rae Osborn, Ph.D. - September 03, 2024

Before the discovery of alpha-gal syndrome, it was unfathomable that an allergy could be transmitted like other infectious illnesses. Now we know that red meat can be bad for you if you have a history of tick bite fever or suffer from a chronic disease.

In this article, we will explore the causes and symptoms of alpha-gal syndrome in detail and explore how it can be diagnosed and treated. Myths about red meat allergy will also be dispelled along the way.

What Is Alpha-Gal Syndrome?

Alpha-Gal Syndrome is the official term used to describe red meat allergy. In recent years, it has been discovered that the lone star tick and other tick bites can cause alpha-gal syndrome. Alpha-gal refers to galactose-alpha-1,3-galactose and is a sugar found in most mammal animal products, including red meat, gelatin, and dairy. Those with the syndrome are allergic to alpha-gal, which is why they react to these products.

If you have never heard of alpha-gal syndrome, you are not alone. Surveys conducted over the last decade reveal that more than half of doctors do not know about alpha-gal syndrome or tick bite meat allergy, and of those that do, most do not know how to treat it.[1]

It is not a typical type of allergy either, making it very easy to miss the signs and symptoms. Most allergies begin in childhood, are protein-related and are not due to carbohydrates (as in the case of alpha gal), do not arise from a tick bite, and do not present with delayed symptoms. Those bitten by a tick may only acquire alpha-gal syndrome weeks to months after the event, further confounding diagnosis. It will take some time before doctors are able to swiftly diagnose alpha-gal syndrome, making it more important to understand the symptoms, triggers, and what to do to treat it.

How Common Is Alpha-Gal Syndrome?

Most reports concerning red meat allergy are from the US and Australia, where it was first discovered. According to CDC reports between 2010 and 2022[2], alpha-gal syndrome has been identified in over 110,000 people so far. Due to a lack of awareness, the numbers are thought to be a lot higher, and it is estimated that there are up to half a million people living with red meat allergies in the US.

The worldwide prevalence of alpha-gal syndrome is not currently understood. Several thousand cases have been documented from countries all around the world, including Europe, the UK, Turkey, Korea, Japan, Brazil, Australia, and South Africa.

When Was Alpha-Gal Syndrome First Discovered?

Alpha-gal syndrome was discovered in 2009, when it was reported to be caused by alpha-gal in mammalian meat products. Early reports can be traced back to 2003 when an unusual proportion of cancer patients were found to react to the chemo-drug cetuximab. It was later clarified to be an alpha-gal allergy related to rocky mountain spotted fever caused by lone star tick bites. Other ticks from all over the globe are now known to cause the allergy as well. Alpha-gal syndrome is believed to be around for much longer before it was officially diagnosed.

How Does Alpha-Gal Syndrome Work?

Alpha-gal syndrome is caused by immune sensitization to the alpha-gal sugar, resulting in the production of IgE antibodies that give rise to heightened allergic reactions. It is still unclear how the lone star tick causes red meat allergy in some individuals and not others.

It is currently hypothesized that ticks might carry different amounts of alpha-gal, alpha-gal laden pathogens, and other toxins in their saliva, which trigger the syndrome. This is supported in mice studies where tick saliva alone was enough to trigger red meat allergy.[3]

It is also thought to affect individuals who are predisposed to allergy more frequently than others. Those with a history of atopic allergy and similar diseases may be at a higher risk for contracting alpha-gal syndrome.

Alpha-Gal Syndrome Symptoms

Symptoms of red meat allergy are known to vary from mild to severe. Those with the condition may experience any of the following within 6 hours of consuming mammal animal products:

• Difficulty in breathing
• Irregular heartbeat
• Dizziness or faintness
• Sudden drop in blood pressure
• Cough
• Skin rash, itching, or hives
• Rapid swelling of the face, lips, or tongue (Angioedema)
• Stomach or abdominal pain
• Heartburn or indigestion
• Nausea or vomiting
• Diarrhea

Red meat allergy onset is most often delayed, commonly occurring within 2-6 hours after consuming mammalian products. This is thought to be related to fat absorption, as alpha-gal sugar is often found in foods linked to fat. Many patients report symptoms late at night after a dinner meal that contains red meat. Some individuals have an even longer delayed reaction, experiencing symptoms 12-24 hours after consuming red meat. This is highly unusual for an allergic reaction.

In a few cases, a red meat allergy can occur within minutes and lead to anaphylaxis, although anaphylaxis is commonly reported to be delayed. Anaphylaxis is a potentially life-threatening emergency that demands immediate hospitalization. However, most cases of alpha-gal syndrome are not life-threatening. Quick reactions are thought to be more common for medications containing alpha-gal than for animal products, possibly due to digestive differences.

Few studies have begun to report long-term effects in patients living with alpha-gal syndrome, such as chronic joint pain and pseudoarthrosis. Symptoms improve immediately after alpha-gal is removed from the diet.

Alpha-gal Sensitivity Might Be Another Reason to Limit Eating Meat

Humans and some primates do not have the ability to produce alpha-gal. It is theorized that we traded this ability 20-28 million years ago for better immunity against pathogens. Our bodies naturally produce IgG, IgA, and IgM antibodies against alpha-gal, which helps the immune system target many harmful gram-negative bacteria that carry this sugar in their membranes.

This may be yet another reason why healthcare experts ask to limit red meat in your diet, as these antibodies are implicated in causing food sensitivities and could give rise to mild symptoms if one consumes too much alpha-gal.

The Link Between Alpha-Gal Sensitivity and Chronic Disease

Alpha-gal antibodies seem to be related to symptom severity across various diseases, such as atherosclerosis, coronary heart disease, thyroid disease, and IBS.

The implications are far-reaching and suggest that one’s tolerance to alpha-gal may be affected by low-grade inflammation, immune changes, other allergies, or other disease-related processes. It could also mean that those with similar diseases may be sensitive to red meat and dairy and that they may be at a higher risk of contracting alpha-gal syndrome after a tick bite. More research is required to confirm these findings.

Common Triggers

If you have alpha-gal syndrome, these are common triggers to avoid:

• Red meat is the most common trigger for symptoms of alpha-gal syndrome. Out of all types of red meat, porcine meat is known to be the most offensive trigger. Kidney, liver, and other organ meats may produce worse reactions as they contain much higher amounts of alpha-gal than muscle meat. Some patients may not react at all to muscle meat from non-porcine sources. Red meat allergy is not triggered by chicken, fish, or eggs, as these do not contain alpha-gal.
• Gelatin also contains alpha-gal and is an often hidden ingredient in commercial sweets, icing, cakes, and other desserts. It may also be a component of medicine capsules, although vegetable alternatives are commonly used these days.
• Dairy products, including milk, cream, butter, and cheese, contain alpha-gal in lower doses yet may still trigger a reaction. Many dairy products, especially cheese, contain extra thickening agents that can promote reactions, including carrageenan and gelatin.
• Red Algae or Seaweed. Carrageenan is a type of sugar extracted from red algae or seaweed that is often used in food products as a thickening and binding agent. It contains a variant of alpha-gal that can trigger reactions in those with red meat allergies. Carrageenan can be found in commercial juice, alcoholic beverages, cheese, processed fish, medications, food-grade supplements, personal care products, and many other processed foods. Other types of algae or seaweed may also contain alpha-gal as reactions have been reported.[4]
• Medications. Chemo drugs, vaccines, antivenom, and mammal-derived digestive enzymes can all trigger red meat allergy by containing bovine or porcine products that have alpha-gal. It is best to discuss any prescriptions you are taking with your doctor beforehand to avoid reactions.
• Biological Heart Valves. Some of the best available heart valve replacements are made from bovine tissues, which contain alpha-gal. These may be problematic for those with alpha-gal syndrome, especially if they begin to degrade, which commonly occurs 3 years post-surgery.

Factors Known to Heighten Red Meat Allergy

Some patients with alpha-gal syndrome do not always experience a reaction to red meat and other mammalian products. This is likely due to differing degrees of sensitivity amongst patients. The following factors may also be implicated as they can lower one’s tolerance to select allergens and provoke heightened reactivity:

• Exercise
• Non-steroidal anti-inflammatories
• Menstruation
• Alcohol

These factors can also increase the risk for anaphylaxis in those with allergies, including red meat allergy.

Alpha-Gal Syndrome Myths

As a sudden emerging phenomenon, some people are worried that tick bite meat allergy may be a hoax. Unfortunately, the reality of red meat allergy is not a myth, yet some of the facts circulating about it are, such as:

Red Meat Allergy Prohibits Organ Donation or Transplantation. Alpha-Gal Syndrome cannot be passed on in donated organs unless they are from pigs or cows. Humans and some primates do not actually have alpha-gal sugar in their tissues or organs. If you are allergic to red meat and have been diagnosed with alpha-gal syndrome, you can still sign up for a human organ transplant if you need one. Some labs have made genetically modified pigs that do not contain alpha-gal sugar, meaning that bioidentical heart valves and organ donation may be an option in the future.[5]

Alpha-gal Syndrome is not an Autoimmune Disorder. Allergy and auto-immunity are entirely different conditions with distinct immune profiles. Alpha-gal syndrome is an allergic condition, and those with allergies may be at a higher risk for red meat allergy. Symptoms might overlap with auto-immune conditions, such as Psoriasis, Eczema, and Lupus. Although some diseases have been linked to alpha-gal sensitivity, more research is needed to clarify whether an auto-immune condition might increase one’s risk.

Covid or Vaccines Cause Alpha-Gal Syndrome. There are no reports of COVID-19 or anti-covid vaccines causing red meat allergy or increasing the production of allergenic IgE antibodies. Several vaccinations contain gelatin and other bovine products that may cause symptoms in those who are already allergic[6]. Alpha-gal antibodies are a natural part of the immune defenses, and some research has begun to show that healthy alpha-gal antibodies help to lessen the severity of COVID-19 symptoms.[7]

How Long Does Alpha-Gal Syndrome Last?

It is difficult to know if alpha-gal syndrome is permanent or not, as it is relatively under-studied, and new cases are being reported globally all the time.

In studies across Europe, the average person with red meat allergy was in their 50s or older, suggesting that it may be a life-long condition. Some individuals report only experiencing symptoms for a number of years following their tick bite and are able to consume alpha-gal products at a later date.

More research is needed to understand if there is a way to condition the immune system to be more tolerant after sensitization to alpha-gal and why some people are more sensitive than others.

Can Alpha-Gal Syndrome Be Caused By Something Other Than A Lone Star Tick Bite?

In the decade since the discovery of tick bite meat allergy, scientists have found out that the lone star tick is not the only tick that causes red meat allergy. Common deer ticks and others of the amblyomma, haemaphysalis, and ixodes types can also sensitize one to red meat and are the main culprits behind global reports. This means that tick-borne illnesses like babesiosis and Lyme disease can cause red meat allergies as well. Additionally, chiggers or harvest mites could possibly cause alpha-gal syndrome in those bitten by larvae but more research is needed.[8]

Due to its possible connection to various diseases, more causes of alpha-gal syndrome could be revealed in the future.

Diagnosis

It is important to see a doctor for a medical examination and history to get a proper diagnosis. An alpha-gal syndrome test ought to be performed if the patient has had a tick bite at any time in the past, exhibits symptoms of allergy, and regularly consumes products high in alpha-gal.

Alpha-gal syndrome can be tested using either ELISA testing or the skin prick test. These are commonly used for detecting allergies. Testing is known to be inaccurate due to the wide range of sensitivity amongst those with the syndrome and is not a foolproof way to tell if you have a red meat allergy.

Alpha-Gal Syndrome Treatment

There are no treatments available yet for those with alpha-gal syndrome but the symptoms of the allergic reaction can be treated. Doctors who know about it are advising patients to avoid all potential triggers and treat the condition like one would treat any other severe allergy.

Common treatment options can help to delay severe reactions before one reaches the hospital, such as:

• Medications. Omalizumab, along with over-the-counter antihistamine drugs can quickly suppress an allergic reaction by lowering histamine.[9]
• Carrying Around an EpiPen. An EpiPen is a portable injection device that contains epinephrine and is used to relax the muscles of the airways during a severe reaction. If you know you are at risk of red meat allergy anaphylaxis, it is best to have an EpiPen on hand.

Going On An Alpha-Gal Syndrome Diet

An ideal diet for alpha-gal syndrome depends on the person’s sensitivity and requires some investigation to pinpoint their unique triggers. The first recommendation is to cut out all red meat from the diet, especially porcine and organ meats. Some patients may be able to tolerate dairy, while others cannot. Fatty dairy, such as ice-cream, may be especially problematic. If symptoms still persist, all dairy can be cut out, and other sources of alpha-gal need to be weeded out of the diet, such as gelatin and carrageenan. Additionally, a healthy diet high in nutrients and fiber may be helpful for lowering immune reactivity.

Checking Medications and Supplements. It is vital to check all ingredients in any medications or supplements you are taking to ensure they do not contain animal products like gelatin. This includes the non-active ingredients which are readily overlooked, such as magnesium stearate.

Being Careful with Exercise and Other Lifestyle Factors. Symptoms may intensify after exercise, during infection, or while menstruating. Certain foods may only become triggers in the presence of these factors. A person with alpha-gal syndrome should not avoid exercising but should rather avoid triggers that do not allow them to exercise safely.

Conclusion

Alpha-gal syndrome is an atypical red meat allergy caused by a tick bite from several types of tick. Tick bites can sensitize susceptible people to alpha-gal, a sugar found in mammal meat products and seaweed. Red meat allergy can provoke a delayed life-threatening anaphylactic reaction that is likely to be a larger problem than currently realized due to a lack of awareness and testing. Those with chronic diseases and other allergies may be more at risk after getting a tick bite than others. Treatment involves preventing severe allergic reactions with antihistamines and avoiding potential dietary and lifestyle triggers.

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Sources:

• [1] https://www.actasdermo.org/es-the-alpha-gal-syndrome-is-underdiagnosed-avance-S0001731023006373
• [2] https://www.cdc.gov/media/releases/2023/p0727-emerging-tick-bites.html
• [3] https://www.emjreviews.com/wp-content/uploads/2018/07/The-Oligosaccharide-Galactose-%CE%B1-13-Galactose....pdf
• [4] https://alphagalinformation.org/carrageenan/
• [5] https://www.sciencedirect.com/topics/medicine-and-dentistry/xenotransplantation[6] https://pubmed.ncbi.nlm.nih.gov/33735861/
• [7] https://pubmed.ncbi.nlm.nih.gov/33009829/
• [8] https://www.jaci-inpractice.org/article/S2213-2198(18)30449-5/fulltext
• [9] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8344025/

 

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