More than 90% of America's food allergies are triggered by 9 foods.

The science of food allergies

Why do certain substances trigger an immune response while others don't? Listen to researchers explain the science in this five-minute video. Food allergies affect around 8% of children and 2% of adults in the US, and—unlike sensitivity or intolerance—they involve the immune system mistaking certain harmless proteins in foods as dangerous invaders, triggering a rapid and sometimes severe defense response.

Adults are developing food allergies that they didn’t have as children

Research published in 2019 found that almost half of 40,000 surveyed adults with food allergies developed a new food allergy as adults, underscoring that our immune systems may newly misclassify substances later in life.

Unlike food allergens, encountering inhaled allergens—like pollen—rarely causes life-threatening illness.

Kids often grow out of allergies to milk and eggs

Between 60% and 80% of kids with allergies to milk or eggs outgrow them by age 16. The immune system doesn’t always recognize and respond to baked forms of these allergens, so when kids eat muffins and other cooked food products, their immune system may become more habituated to them and overcome food sensitivities. Aging out of other allergies is less common.

Amish kids have far fewer allergies than the general population

Only about 7% of Amish children in a northern Indiana community have tested positive for common allergens in routine skin prick tests, whereas half of the general US population tests positive for them. Asthma is also extremely uncommon among the Amish, even when compared with other farming communities. Researchers are interested in exploring if approaches like exposing kids across the general population to Amish farm dust might stave off some allergies.

One-third of kids with food allergies report being bullied because of it, surprising parents

Research published in 2021 surveyed how more than 100 kids with food allergies were treated by their peers. About one-third of the surveyed kids had their allergies used against them. Bullying tactics included that their allergens were sometimes intentionally put in their food or thrown at them. Parents usually had no idea this bullying was happening.

CRISPR technology is removing allergens from common foods

Proteins responsible for allergies to eggs, milk, wheat, peanuts, and other foods can be genetically edited out of foods to reduce the risk of life-threatening reactions. The technique has also been used to produce caffeine-free coffee beans, spicier tomatoes, allergen-free pets, and more nutritious fish.

Less than 1% of Americans are allergic to penicillin, though about 10% of Americans believe they have this allergy.

Find dozens of allergen-free recipes

This collection of allergen-free meal and snack recipes, designed by celebrity chefs and others, was curated by the nonprofit Food and Allergy Research & Education group. It includes items like taquitos, pizza, chickpea burgers, various desserts, and more.

Allergies occur when our immune system mistakenly considers a substance a threat

Immunoglobulin E antibodies, or IgE antibodies, may bind to an allergen, effectively labeling it as a threat. That triggers a cascade of actions in the body, including the release of histamine, which causes the characteristic itching and hives of allergies. Sometimes a cooked version of an allergen—like a cooked carrot—may look different enough from its raw form to the immune system that antibodies ignore it, and no allergic response takes place.

Food allergies were first documented more than 4,000 years ago.

Modern conveniences may be contributing to allergy increases

A combination of genetics and how the environment changes our genes are likely contributing to the rise in allergies. But daily conveniences, such as dishwashers and packaged baby food, also change the level of bacterial exposures in early life, with potential implications for allergy development, experts from Mount Sinai Health System state in this video discussion.

One in six Americans contracts food poisoning each year.

Most penicillin allergy diagnoses are wrong, leading to costlier, less effective treatments and contributing to the growing problem of antibiotic resistance.

Inhalers, antihistamines, immunotherapy, and more have made allergies a multimillion-dollar market

Market research suggests that the allergies market will continue to grow in the years ahead as the number of allergy diagnoses increases, identifying new patients. Areas of growth include the increasing interest in immunotherapies designed to retrain the immune system through regular exposure to potential allergens via injections and under-the-tongue medical formulations, among other approaches.

Tick bites can fuel an allergy to a sugar molecule in red meat

Alpha-gal syndrome is on the rise globally as ticks spread due to climate shifts. Bites from some ticks can trigger a sensitivity to a sugar molecule called alpha-gal found in mammal meat, which can lead to allergic responses to hamburgers and steak, among other products. Listen to an expert’s tips for avoiding this allergy, including quickly removing any ticks to limit exposure to their saliva or vomit.

Allergy tests identify antibodies, but not whether allergy symptoms may appear

Skin prick tests and blood tests, the two most common allergy tests, both detect the presence of allergen-specific antibodies. But just because the body has those antibodies doesn’t mean that a person is “allergic” to a substance or that they will develop symptoms of an allergy when encountering the substance. Allergists work with families to interpret the results and sometimes combine that data with approaches including exposure challenges—giving someone a tiny bit of the food or substance they may be allergic to—under medical supervision.

In 1982, around 20% of the people who ate some of the roughly 7,400 bags of cashews sold as part of a Little League fundraiser in Pennsylvania broke out in rashes because of natural urushiol residue on the nuts' shells that hadn't been removed and fully cooked off—the same allergy-inducing substance found in poison ivy.

Mycotoxins are toxic compounds produced by fungi—some show up in food

About a quarter of the world’s agricultural products are contaminated with mycotoxins. Some of these compounds can cause serious health problems, including cancer, so the US government has set up monitoring programs to detect them in our food and in animal feed. Humans can become ill if they eat contaminated food, but also if they ingest products from animals that had previously consumed these toxic compounds, such as milk from a cow that ate contaminated corn.

FDA approved the first ever peanut allergy treatment in January 2020

This new medication, called Palforzia, is designed to stave off severe reactions from accidental peanut exposures with a daily dose that is increased over time under an allergist’s supervision. It’s not a treatment that should be administered during an allergic reaction, however. Epinephrine, usually administered via injection, remains the intervention for severe reactions.

Peanut allergies dropped by 43% after doctors reversed avoidance guidance, but questions remain

The study’s data appear to confirm the policy shift. Still, since the study did not include an examination of infant diet, researchers can’t definitively say that the guideline shift led to dietary changes and thus directly caused the decline.

The five most common chemicals found in modern food

Most modern processed foods rely on a number of preservatives to stay fresh from production to our plates. The most common include citric acid (preservative and flavor), sodium benzoate (preservative), xanthan gum (thickening and stabilizing), carrageenan (thickening), and red dyes 3 and 4 (for color).

Most of the world’s population has difficulty processing lactose—but that’s not an allergy

Lactose intolerance is a digestive condition that occurs when the small intestine has difficulty breaking down lactose, a sugar found in products like milk or cheese, leading to symptoms such as diarrhea or bloating. Almost 70% of the world’s population may have lactose processing issues, particularly in Asia and Africa. This is different from a condition called cow's milk protein allergy—an immune system disorder that can cause hives and anaphylaxis.

Alpha-gal allergy is a problem for red meat lovers, and that same alpha-gal sugar is an issue for xenotransplants, too—since it's present in pigs, human bodies reject pig-to-human transplants as foreign once they detect the substance.

Wichita is the worst US city to live in if you suffer from seasonal allergies

More than 100 million people in the United States suffer from allergies each year. But Wichita, Kansas, tops the charts year after year as the worst city in America for those suffering from seasonal allergies. Longer and more intense pollen allergy seasons, however, are increasing the burden of living with seasonal allergies in numerous locations across the country.

The word allergy is partly derived from the Greek word 'allos' for 'other'

For people with allergies, their immune systems recognize substances as a harmful "other"—cuing an inflammatory response. This podcast explores allergy details and related topics, including how scientists are interested in if the same allergic response mechanisms could underpin other health issues, including severe, painful symptoms around the time of menstrual cycles. Since estrogen acts on white blood cells called mast cells, which leads to the release of histamines—similar to what happens during allergic responses—an understudied question is whether the same process is fueling some of the uncomfortable symptoms around menstruation. An allergist guest notes this raises questions about if antihistamine medications like Pepsid might alleviate them, something that hasn't yet been explored in clinical trials.

More than 5 million Americans have more than one autoimmune disease

Overall, about 4.6% of the US population—15 million people—have an autoimmune condition. Some common examples include rheumatoid arthritis, psoriasis, type 1 diabetes, Grave's disease, and autoimmune thyroiditis.

Why some people have allergies

Why do some people have allergies while others don’t? One theory suggests allergies are a relic of our evolutionary past. Our immune system, once primed to fight parasites, now mistakes harmless substances for threats.

Ultraprocessed foods include preservatives, dyes, sweeteners, and more

Processed foods are those that have been altered from their original state, which includes numerous processes that we consider natural, such as cooking or salting. Ultraprocessed foods contain at least one item that wouldn’t be found in a kitchen, like hydrogenated oils or high-fructose corn syrup. It’s estimated that nearly 75% of all foods consumed in the US are ultraprocessed, though that doesn’t mean that all of them are unhealthy. In fact, some, such as prepackaged whole wheat bread and soy milk, are recognized for their health benefits.

Zoo animals have developed allergies, too

Although scientists do not know if allergies manifest among wild animals—and if animals can survive with them—in a zoo setting, veterinarians have observed zoo animals with common allergy symptoms, including itchiness, crusty skin, and runny eyes. Veterinarians have identified Asian elephants with pollen allergies and at least one jaguar with an allergy to fleas.

Seasonal allergies don't always show up in childhood

The human immune system may become sensitized to pollen and develop an allergic reaction to it after prolonged exposure. Other triggers for new seasonal allergies may include exposure to new environments and changing climate conditions that affect allergy season length and conditions for various pollens.

Contributing to one in every three bites of food consumed by humans, bees are a keystone species because of their essential role as pollinators of about 80% of all flowering plants worldwide.

Restaurants are where most of us contract food poisoning in the US.

Sesame seed regulations have led to fewer sesame-free products

Food producers have been required to include specific labeling on their packages for sesame since new regulations went into effect in January 2023. In response, some food producers have decided to add small amounts of sesame to foods, including breads, rather than do the costly work of scrubbing their facilities of all possible sesame contamination.

Gut microbiome rewrites may help reduce allergies

Researchers are investigating different strategies to determine if one day they could give people a combination of gut microbes to set them up for fewer allergies. In animal research, scientists have already prevented severe allergic responses in allergy-prone mice—supplying them with gut microbes from healthy, non-allergic human babies.

Autoimmune disease prevalence and incidence are on the rise—but no one knows why

Researchers theorize that environmental factors, including shifts to less healthy diets, air pollution, infections, stress, climate change, and exposures to xenobiotics—substances like pesticides, plastics, and toxins that incite immune responses—may all be fueling epigenetic changes to our bodies that make people's immune responses go awry.

How the Great Depression still shapes the way Americans eat

From fortified foods to nutrition labels, the legacy of an early financial crisis lives on in kitchens across the United States. Ethnic foods with their (supposedly) hunger-triggering spices were vilified and considered “stimulants” along the lines of caffeine and so, in their stead came prune puddings, canned-meat stews, and dairy-heavy vegetable casseroles featuring America’s first fortified foods. Read more here.

97% of Americans polled say they like or love ice cream

Twin studies suggest celiac disease is among the more genetically-linked disorders

Genetics appear to play a larger part in this condition's development than many other autoimmune disorders. Research shows a roughly 60-75% genetic probability that if one identical twin has it, the other will too. Celiac triggers a small intestine attack when people eat gluten, a protein commonly found in wheat, barley, and rye.

Researchers are investigating if nanoparticle treatments could combat allergies

In rodent work, Northwestern University’s Evan Scott (now at the University of Virginia) and his colleagues have been trying to attack allergies with specially designed nanoparticles—miniscule lab-made objects that can penetrate cells. They stud the nanoparticles with a tiny bit of the allergen specific to the allergy (i.e. cashew protein for cashew allergy) and antibodies that shut down allergic response processes.

Poison ivy is in the same family as mangoes, cashews, and pistachios, and they all produce oily urushiol in their raw, unprocessed state—but they are typically prepared in ways to avoid causing human discomfort.

You can be allergic to grass—but there are other reasons it can make you itch

Health food broke into the mainstream by the 1980s

A 1984 New York Times story noted that Americans were eating less red meat than a decade prior, and that, in general, the country was “talking, thinking and worrying about what they eat to a degree unique in the nation's history.” The feature then details foods that were then considered bizarre: whole-grain muffins, hummus, and a variety of vegetarian dishes. (Some readers may experience a paywall.)

Food poisoning investigations have led to more than 1 billion pounds of food recalls

PulseNet is the US government’s real-time foodborne illness tracking system for leading causes of food poisoning. There, a network of labs and scientists share DNA sequences for pathogens collected from contaminated food and also from sickened individuals, looking for patterns in the pathogens’ genome sequences that will help them hopefully finger a certain food, warehouse, producer, or restaurant.

Alcohol use disorder is the most common addiction in the US

This comprehensive overview from the Addiction Center uses recent data from SAMHSA’s National Survey to examine the 10 most common substance dependencies in the United States. It ranks addictions from alcohol (affecting 28.3 million Americans) to barbiturates, while highlighting key trends, risks, and societal impacts.

More than 20 mosquito-borne and tick-borne diseases are found in the US

Children, older adults, and people with compromised immune systems are at particular risk of poorer health outcomes from these diseases. But dog owners and outdoor enthusiasts are among those at particular risk of contracting these illnesses, which include Lyme disease, Zika, and the condition Alpha-gal Syndrome.

Most of the 86,000 consumer chemicals registered with the US EPA have never received rigorous toxicity testing, though not all those are still in current use.

Lyme disease is the most common vector-borne illness in the US

In the US, ticks account for 90% of all disease transmission from bites, including mosquitoes. And Lyme disease is the most common vector-borne disease in the US overall, with estimates suggesting there are about 475,000 Lyme cases annually across the nation.

Between 2003 and 2023, nearly 5M Americans lived in food deserts, elevating their risk for conditions linked to unhealthy nutrition, including cancer, heart disease, and diabetes.

Why processed foods can be so addictive

In recent years, many critics have voiced their concerns about the food industry and how ultra-processed foods affect our health. Despite our awareness of these issues, processed foods are still incredibly hard to remove from our diet. In this podcast by The Guardian, Dr. Chris van Tulleken explains how “junk food” is created to get us hooked, how it negatively affects us, and what we can do to improve our eating habits.