Are Food Allergies Genetic? What Actually Causes Food Allergies?

Genetics of food allergies

Food allergies are a significant health issue in the United States, affecting roughly 33 million people (1 in 10).

These allergies are the immune system’s mistaken response to food proteins, which can cause reactions ranging from mild itching and rashes to severe, life-threatening anaphylaxis.

But what causes food allergies? Are they inherited from our parents or influenced by our environment and diet? In this article, we’ll dive into the world of “genetics of food allergy” to understand if food allergies are genetic, or inherited along with other aspects of food allergies.

Whether you’re dealing with food allergies yourself, know someone who is, or are just interested in learning more about “allergies of food” and “allergic reactions to food,” this article aims to provide useful and easy-to-understand information.

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What Causes Food Allergy?

Food allergies occur when the body’s immune system mistakenly identifies a harmless food protein, known as an allergen, as a threat. This leads to the production of immunoglobulin E (IgE) antibodies against the food. Upon subsequent exposure to the allergen, these IgE antibodies trigger an allergic reaction. Food allergies can be activated through ingestion, skin contact, or inhalation of allergenic food particles, causing the immune system to react by releasing chemicals like histamine, which result in allergy symptoms.

The most common allergies in children are to peanuts, milk, shellfish, and tree nuts, while adults frequently react to shellfish, milk, peanuts, and tree nuts, with sesame allergy also on the rise.

Difference Between Food Allergy and Food Intolerance

Understanding the difference between food allergies and intolerances is crucial.

While allergies involve the immune system and can be severe, intolerances mainly affect digestion, leading to discomfort without the immune system’s involvement.

Types of Food Allergies (Symptoms & Causes)

There are mainly three types of food allergies.

IgE-mediated Food Allergies

This type is the most familiar form of food allergy. It happens when your body creates a kind of defender called immunoglobulin E (IgE) antibodies against food proteins it wrongly sees as harmful. This mistaken identity causes allergic reactions.

Symptoms of an IgE-mediated food allergy can pop up within a few minutes to a few hours after eating and include:

  • Hives or skin rash
  • Swelling in parts of the mouth or face
  • Itching or a weird feeling in the mouth
  • Trouble breathing or swallowing
  • Wheezing or coughing
  • Stomach upset, vomiting, or diarrhea
  • Feeling dizzy or passing out
symptoms of food allergies

In severe cases, this type of allergy can lead to a dangerous reaction called anaphylaxis, needing quick medical help.

This reaction can lower blood pressure suddenly, change the heartbeat, cause unconsciousness, or even shock.

Common culprits include

  • peanuts
  • tree nuts like almonds or walnuts
  • eggs
  • milk
  • fish
  • shellfish like shrimp
  • soy
  • wheat.

These foods are behind about 90% of all food allergies in the United States. However, any food can trigger this allergy, and some people might react to more than one food.

Non-IgE-mediated Food Allergies

These allergies are less common and not as well understood. They don’t involve IgE antibodies but are caused by other parts of the immune system reacting to food proteins.

The symptoms can take hours or days to show up and might include:

  • Eczema or skin rash
  • Belly pain or colic
  • Throwing up or diarrhea
  • Constipation or finding blood in poop
  • Reflux or spitting up food
  • Not growing well or losing weight

This type of allergy can affect different parts of the body, like the gut, skin, or lungs. Some specific forms are:

  • Food protein-induced enterocolitis syndrome (FPIES), causing severe vomiting and diarrhea
  • Food protein-induced allergic proctocolitis (FPIAP), leading to bloody stools, affecting babies
  • Eosinophilic esophagitis (EoE), which inflames the esophagus, causing swallowing problems, food getting stuck, or chest pain
food allergy genetics

Common triggers include milk, soy, grains like rice and oats, eggs, fish, chicken, and turkey, but like with IgE-mediated allergies, any food can potentially cause a reaction.

Mixed IgE and Non-IgE-mediated Food Allergies

A rare and complicated type that involves both IgE and non-IgE responses. This can lead to various symptoms across different body parts, with severity and timing that vary. Examples include:

  • Eosinophilic gastroenteritis (EGE), causing inflammation in the digestive tract
  • Atopic dermatitis (AD), leading to dry, itchy skin, which certain foods can trigger or worsen
  • Oral allergy syndrome (OAS), causing mouth or throat itching or swelling due to reactions between certain foods and pollen

The foods causing mixed reactions can vary, but often include milk, eggs, wheat, soy, peanuts, tree nuts, fish, shellfish, fruits, vegetables, and spices.

Understanding the types and triggers of food allergies, including the role of genetic testing for food allergies and DNA testing for food allergies as we will discuss later, is crucial for managing and potentially preventing allergic reactions to food.

Genetics of Food Allergies

Food allergies are a widespread issue that can range from mild discomfort to life-threatening situations for millions around the globe. But have you ever wondered why some people have food allergies and others don’t?

Are these allergies something we’re born with, or do they develop from our environment?

This discussion delves into the genetics of food allergy, exploring how DNA plays a role and the impact of genetic testing for food allergies.

Are Food Allergies Genetic?

Yes, food allergies can indeed have a genetic basis; however, the likelihood of developing these allergies is also significantly shaped by a combination of both genetic predisposition and various environmental factors.

While genetics can pass down the potential for allergies from one generation to the next, it’s the shared environments and lifestyle choices that often activate or intensify these allergies.

For instance, similar dietary habits, exposure to certain allergens, and living conditions within a family can all play crucial roles in the emergence of food allergies.

food allergy genetics

Are Food Allergies Inherited?

Genetics significantly influence the likelihood of developing food allergies. If your parents or siblings have food allergies, you might be more prone to them as well. This family connection suggests that food allergies can be hereditary or inherited, a concept known as familial aggregation.

But inheriting the genes doesn’t guarantee you’ll have food allergies. Environmental factors like what we’re exposed to, our diet and even our gut bacteria also play a part.

This makes food allergies a complex trait, shaped by a mix of genetic and environmental elements.

How Genetics Influence Food Allergies

To understand the genetic aspect, scientists look at food allergy heritability – essentially, what portion of this allergy risk comes from our DNA.

By studying different family members, especially twins, researchers can see how similar their food allergy statuses are. One study showed a 65% concordance in identical twins with a peanut allergy, compared to 10% seen among dizygotic pairs.

This high heritability means genetics play a big part; low heritability suggests other factors are also at play.

More research shows food allergies have a moderate to high heritability, indicating a strong genetic component, but environmental influences can’t be ignored. These studies suggest a range of 0.3 to 0.8, depending on the specific allergy and population group. This indicates a significant genetic component but also leaves room for environmental influences to play a role.

Discovering Specific Genes

We have used genome-wide association studies (GWAS) to find specific genes linked to food allergies.

It’s done by comparing the DNA of people with food allergies to those without, looking for differences that could explain why some people develop allergies.

These studies have pinpointed several genetic areas, especially related to peanut allergies, one of the most common and severe allergies.

One key area is the HLA region on chromosome 6, involved in the immune system’s response to foreign substances.

Certain types of HLA can make someone more likely to see food proteins as threats, leading to allergies.

Another crucial gene is filaggrin (FLG), which helps maintain the skin’s barrier. Mutations in this gene can weaken the skin’s defense against allergens, increasing the risk of food allergies, particularly peanut allergies.

Filaggrin Mutations and Food Allergies

Filaggrin mutations are a notable genetic factor in food allergies. This protein is crucial for keeping the skin healthy, acting as a barrier against allergens.

People with mutations here might have drier, more permeable skin, making it easier for allergens to enter and trigger an immune response.

Remarkably, up to half of the individuals with peanut allergies have these mutations, highlighting their importance in understanding food allergies.

In short, while food allergies are influenced by both genetics and environment, genetic testing for food allergies, including DNA testing, can offer insights into one’s risk and potentially guide management and prevention strategies in some cases (as we are still understanding this puzzle).

The genetics of food allergy research is still evolving, but it’s clear that understanding our DNA can provide valuable clues on how to tackle these allergies.

Environment and Allergies

Why are more people, especially kids, getting food allergies than ever before?

Studies, like those from the CDC, show a big increase in food allergies over the past few decades.

For example, there’s a notable increase in food allergy prevalence, with a 50% rise among children between 1997-1999 and 2009-2011. Peanut or tree nut allergies in children tripled from 1997 to 2008.

It seems our changing environment or way of living might be making us more prone to allergies.

One theory called the hygiene hypothesis, suggests that not being exposed to enough germs early in life could make our immune systems overreact to harmless things, like food. This theory also looks at how using antibiotics, vaccines, and antiseptics might change how our immune systems work, possibly making us more likely to get allergies.

Another theory, the dual allergen exposure hypothesis, thinks it matters how and when we first come into contact with food that can cause allergies. It suggests that getting a little bit of these foods through the skin, maybe from creams or dust, could make us allergic. But, eating these foods in larger amounts early on might actually stop allergies from developing.

Role of Microbiome

What we eat and the bacteria living in our gut, known as the microbiome, also play a big role.

The microbiome helps with digestion and keeps our immune system healthy. Some research shows that having a variety of good bacteria in our gut might lower the chance of food allergies.

Foods like yogurt, which have beneficial bacteria, might even help prevent or manage food allergies.

Our diet matters too

Eating lots of fruits, veggies, fish, olive oil, and nuts, like in the Mediterranean diet, might protect against allergies. This is because these foods have nutrients that fight inflammation and keep us healthy.

On the other hand, processed and fast foods might increase allergy risks due to their additives and artificial ingredients.

Other environmental factors, like not getting enough vitamin D, pollution, and climate change, might also affect food allergies.

Vitamin D is important for our immune system and not having enough might increase allergy risks.

Pollution can damage our lungs and skin, making us more susceptible to allergies. Climate change might affect food production and allergen levels, changing how and what we eat, and possibly increasing food allergies.

So, it’s not just about genetics; our environment and lifestyle have a huge impact on the rise of food allergies. Understanding these factors better might help us find ways to prevent and manage food allergies more effectively in the future.

How Your Lifestyle Can Also Affect Your Genes

This is where epigenetics comes in. Epigenetics is about how your behavior and environment can change how your genes work. For example, what you eat, the air you breathe, and even your stress levels can change the markers on your DNA.

These changes can influence whether you develop food allergies and can be passed down to your kids, too, without altering the DNA itself.

Research has found that things like a mom’s diet while pregnant can affect her baby’s chances of getting food allergies by changing how the baby’s immune genes work.

Also, being around pollution like diesel fumes could raise the risk of food allergies by tweaking genes related to inflammation and allergic reactions.

Testing Food Allergies

If you think you or your kid might be dealing with a food allergy, figuring out the next steps for testing can be really important.

To tackle allergies, your first move should be to visit a specialist known as an allergist. An allergist will talk to you about the symptoms you’ve noticed, any family history of allergies (since allergies can be inherited or genetic), and what foods seem to cause problems.

They’ll also do a check-up to make sure something else isn’t causing the symptoms.

Here are some tests your allergist might suggest to pinpoint or rule out food allergies:

  • Skin prick test: A common starting point, where a tiny bit of the food in question is placed on your skin, which is then lightly pricked. If you’re allergic, a bump or red spot pops up within minutes. It’s quick and mostly safe but can sometimes be misleading, showing allergies when there aren’t any (false positives) or missing them when they do exist.
  • Blood test: This checks for specific antibodies (IgE) that your body makes in response to allergens. A high level of IgE might mean an allergy, but it’s not always right. Some people have high IgE levels without any allergic reactions, and vice versa. Plus, it’s pricier and slower than skin testing.
  • Oral food challenge: Considered the gold standard but also the riskiest. You’ll eat small, increasing amounts of the suspect food under close medical supervision. No reaction means you’re likely not allergic; any sign of an allergy, and the test stops immediately. This test is only done where emergency help is available.
  • Elimination diet: You stop eating the suspected allergenic food for a while then slowly add it back into your diet. If symptoms go away when the food is gone and return when it’s back, it might be the culprit. However, this method isn’t foolproof, can be hard to follow, and risky if reintroducing the food triggers a strong reaction.

Testing for food allergies involves careful consideration and should be guided by an allergist, who will combine test results with your health history to make a diagnosis.

If a food allergy is confirmed, they’ll guide you on how to avoid the food, recognize and handle symptoms, and use an epinephrine autoinjector for severe reactions.

Genetic Testing for Food Allergies

In addition to the tests mentioned, your allergist might also discuss the option of genetic testing.

Since allergies can run in families, a simple DNA test might show if you’re more likely to have them. This doesn’t mean you’ll definitely get allergies, but it helps to know your risk.

Genetic testing for food allergies involves analyzing DNA to look for specific markers associated with increased risk of allergies. This could include tests for genes known to influence the immune system’s response to foods. If the test says you’re at high risk, you and your doctor can plan better ways to introduce foods to your diet or avoid some allergies altogether.

This test is easy—just a bit of saliva or a cheek swab. It’s getting cheaper and more common, so it’s a good option for many people.

Whether genetics of food allergy or environmental factors are at play, getting professional advice is key to navigating food allergies effectively. Don’t hesitate to reach out to an allergist for testing and management advice.

Preventing and Managing Food Allergies

The complexity of food allergies lies in their unclear origins, though it’s recognized that both genetics and environment contribute.

This means while some people might be more likely to develop food allergies because of their family history, not everyone with these genes will end up with an allergy. Other life factors also play a part.

How to Prevent Food Allergies?

Guidelines advise not to give solids to babies under 17 weeks old. While encouraging breastfeeding for as long as possible.

For peanut allergies, new guidelines in 2017 from the National Institute for Allergy and Infectious Disease offer advice based on whether a baby is at high, moderate, or low risk of developing this allergy.

peanut food allergy

They highlight a big step in preventing peanut allergies, now more common, by suggesting high-risk infants (those with severe eczema or egg allergy) start trying peanut foods between 4-6 months if they’ve begun solid foods and it’s deemed safe by the doctor.

Most babies, though, face a moderate or low risk and can try peanuts at home (when the child is healthy), but whole peanuts are a no-go due to the risk of choking.

Is There a Cure for Food Allergies?

For most food allergies, avoiding the allergen is the only prevention. However, there’s been progress for peanut allergies. In January 2020, the FDA approved Palforzia, the first treatment for kids and teens aged 4 to 17 with peanut allergies. This daily oral therapy helps by gradually exposing the patient to small amounts of peanut protein, reducing the severity of reactions from accidental exposure. Though not a cure, it’s a significant step in managing peanut allergies.

Though there’s no cure for food allergies, there are ways to prevent or manage them, making life safer and more enjoyable for those affected.

Early Introduction of Allergenic Foods

One key prevention strategy is introducing potentially allergenic foods like peanuts, eggs, milk, wheat, soy, fish, and shellfish into a child’s diet early on, around 4 to 6 months old.

This early exposure can help the child’s immune system get used to these foods, possibly preventing allergies from developing.

However, this should be done carefully, especially if there’s a family history of allergies, and always under a healthcare professional’s advice.

Immunotherapy: A Treatment Approach

Immunotherapy offers hope for treating food allergies by gradually getting the immune system used to the allergen through controlled exposure.

This method doesn’t cure allergies but can lessen the severity and frequency of allergic reactions, improving life quality.

Currently, oral immunotherapy for peanut allergies in children is the only FDA-approved treatment, but research is ongoing.

This treatment must be only done by specialists in a setting equipped to handle severe allergic reactions.

Other Important Things In Managing Food Allergies

Understanding Food Labels: The Food Allergy Labeling and Consumer Protection Act (FALCPA) requires clear labeling of the eight most common allergens in packaged foods. However, this law doesn’t cover fresh meat, poultry, certain egg products, alcohol, cosmetics, shampoos, and health and beauty aids. Being vigilant about ingredient labels and aware of precautionary labels like “may contain” is crucial for safety.

Eating Out Safely: Dining out requires extra caution for people who are allergic to food. Inform servers about your allergies and consider using a “chef card” that outlines your allergies clearly. Always verify that the kitchen can accommodate your needs to avoid cross-contamination.

Eating Baked Food: Eating baked foods that contain milk or eggs might help some kids with milk and egg allergies. When milk and eggs are baked, the heat changes the proteins a bit at the molecular level, making them less likely to cause allergies. But, this doesn’t work for all foods, like peanuts, which can become more allergenic when roasted. However, Not all individuals with milk or egg allergies will benefit from this approach.

Dealing with Anaphylaxis: Anaphylaxis is a severe, potentially life-threatening allergic reaction. If diagnosed with a food allergy, you should carry two doses of an epinephrine auto-injector at all times since a second dose may be necessary. Use epinephrine immediately for severe symptoms and then seek emergency medical attention.

Epinephrine Auto-Injectors: Ensure you know how to use your epinephrine auto-injector properly and keep an eye on expiration dates. Epinephrine is safe and the most effective way to treat anaphylaxis, although it may cause side effects like anxiety or dizziness.

The Future: Genetic and Epigenetic Therapies

Looking ahead, scientists are exploring therapies targeting the genetic roots of food allergies. Gene therapy might one day fix the immune system’s misfiring response to food allergens by altering the genes involved. But, it’s yet a far-reached dream.

Another exciting area is epigenetic therapy, which aims to change how genes linked to allergies are turned on or off, offering a potentially reversible treatment option.

These approaches are still in the research phase, with many hurdles to overcome regarding safety and effectiveness.

In short, food allergies intertwine genetics, lifestyle, and environmental factors, making them a complex issue with no one-size-fits-all solution.

Whether food allergies are genetic or influenced by other factors, it’s crucial to work with healthcare professionals to navigate prevention and management strategies effectively.

This collaborative approach can help minimize risks and enhance the quality of life for those dealing with food allergies.

Food Allergies in Kids

Food allergies in kids are pretty common and can seriously affect their health and daily life. These allergies can mess with a child’s eating habits, growth, and overall development.

Kids can be allergic to a variety of foods, but some usual suspects include milk, eggs, peanuts, tree nuts, fish, shellfish, wheat, and soy. The best way to deal with a food allergy is simply to stay away from the food that triggers it.

Parents often wonder, “Are food allergies genetic?” or “Can food allergies be passed down from parents to kids?”

The truth is, while the exact cause of food allergies isn’t crystal clear, experts think it’s a mix of genetics and the environment.

This means if food allergies run in the family, a child might be more likely to have them, too. But it’s not a given—they might not get the same allergies, or any at all. It’s more about the odds being higher.

What else plays into whether a kid might develop a food allergy?

Factors include when and how different foods are introduced into their diet, whether they have other allergies or conditions like eczema and the variety of bacteria in their gut.

Some research suggests that giving foods that often cause allergies, like peanuts, to babies early on might lower their chances of getting an allergy.

But, it’s crucial to talk to a doctor before trying this, especially if there’s a history of allergies in the family.

Do Kids Allergies Go Away With Time?

Kids’ food allergies can change as they grow. Some might go away with time, while others could stick around or show up later. Often allergies to milk, soy, wheat, and eggs fade as kids get older, but tree nut, fish, and shellfish allergies usually stay (they also go away in a few cases). A few studies show that around 25% of kids also outgrow peanut allergies.

In some cases, kids might not completly become immune to these allergies but the reaction might decrease with age.

However, if you got these allergies as an adult, they are most probably going to stay with you.

Managing food allergies means working closely with a healthcare provider to figure out what foods to avoid and having an emergency plan, like carrying an epinephrine auto-injector if prescribed for severe reactions.

It’s also about teaching kids and those around them about food allergies—how to read labels, avoid mixing foods and handle symptoms.

If your kids have allergies, sharing a clear action plan like understanding how to use an epinephrine auto-injector, with schools and caregivers is IMPORTANT.

Final Words On Food Allergies

Food allergies can be partly hereditary, meaning if your family has a history of food allergies, you might be more likely to develop them too. Yet, inheriting these genes doesn’t mean you’ll definitely face food allergies; lifestyle and environmental factors such as diet, cleanliness, health conditions, and even body composition significantly contribute.

This makes food allergies a complicated issue, rooted in both genetics and environment.

Managing food allergies effectively requires staying informed and active in avoiding known allergens, possibly undergoing genetic or DNA testing for food allergies, always having an epinephrine auto-injector handy for emergencies, and spreading awareness about the condition.

FAQs On Food Allergies

Are you born with food allergies, or do they develop?

Food allergies can develop at any time in a person’s life. While individuals are not born with specific food allergies, they may have a genetic predisposition that increases their risk. However, the actual allergies typically develop after the first exposure to the allergen.

Are allergies inherited from the mother or father?

Allergies can be inherited from either parent, or both. The genetic predisposition to develop allergies, known as atopy, can be passed down from the mother, and the father, or can be a combination of both parents’ genetic materials.

Is peanut allergy genetic or hereditary?

Peanut allergies are considered to be both genetic and environmental. If a family member has a peanut allergy or other types of allergies, the risk is higher, showcasing the hereditary aspect. However, environmental factors also play a significant role in the development of peanut allergies.

Do allergic reactions run in families?

Yes, allergic reactions tend to run in families due to genetic predispositions. If one or both parents have allergies, their children are more likely to develop allergies, though not necessarily to the same substances.

Do allergies skip a generation?

Allergies can sometimes appear to skip a generation, but this is more about the variability of genetic expression rather than a consistent pattern. The genetic predisposition to allergies can be passed down, but whether an individual develops allergies can be influenced by multiple factors, including environmental exposures.

Can an allergic reaction occur from touching contaminated surfaces?

Yes, an allergic reaction (mostly mild) can occur from touching surfaces contaminated with food allergens. Skin contact with allergen residues, such as peanut butter or egg, can cause localized reactions like hives. However, for a more severe reaction to occur, such as anaphylaxis, the allergen typically needs to be ingested or enter the body through mucous membranes.

Can airborne allergens cause severe allergies?

While severe peanut allergies can cause concern about airborne allergens like peanut dust, the risk of a severe reaction is lower than often feared. Studies indicate that activities releasing peanut particles into the air, such as cooking or crushing, are unlikely to trigger significant reactions like anaphylaxis. Most allergic reactions are more commonly linked to direct contact with contaminated surfaces rather than inhalation. Importantly, merely smelling peanut products is not associated with systemic reactions. Simple precautions, such as cleaning surfaces where peanuts have been handled, can greatly reduce risk. Nonetheless, individuals with severe allergies are advised to consult their allergist for personalized guidance and continue to exercise caution, especially in environments where peanut products are extensively used.

What is gluten allergy?

Gluten allergy, often confused with celiac disease or non-celiac gluten sensitivity, is a misnomer as true allergic reactions to gluten are rare. Celiac disease is an autoimmune condition triggered by gluten, found in wheat, barley, and rye, leading to intestinal damage. Non-celiac gluten sensitivity involves gastrointestinal and other symptoms without the autoimmune response. Wheat allergy is the true allergic response to proteins found in wheat, not specifically gluten.

At what age do food allergies start?

Food allergies can start at any age, but they are most commonly identified in children, particularly toddlers and infants. Some food allergies may be outgrown during childhood, while others may persist into adulthood.

Do food allergies get worse with age?

Food allergies can change with age. While some individuals may outgrow certain food allergies, others might find their allergies persist or, in some cases, become more severe with age. It varies significantly from person to person.

At what age do you stop developing allergies?

There is no specific age at which individuals stop developing allergies. New allergies can develop at any time in a person’s life, although it’s more common to see new allergies develop in childhood and less common in older adults. However, when adults get allergies, they tend to stick around longer.

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