Can Adults Develop Food Allergies?

food allergy

Story at-a-glance -

  • Most of the processed foods on your grocery store shelves are laden with additives, preservatives, colorings, flavorings and other chemicals that may increase your risk of an allergic reaction
  • Today, 1 in every 13 children has a food allergy and more adults are experiencing new food allergies
  • Researchers are unsure of why the rate of food allergies continues to grow each year, but associations have been found between eating foods laced with antibiotics, impaired gut microbiome, low levels of vitamin D and food allergies
  • If you or someone with you begins to have a severe reaction to food, it is vital you call your local emergency number (911 in the U.S.), administer an autoinjector of epinephrine if available, and remain quiet and calm until emergency personnel arrive

By Dr. Mercola

Most of the processed and packaged foods you find on your grocery store shelves are laden with additives, preservatives, colorings, flavorings and a number of other chemicals designed to make the product look and taste good. However, each of these additional chemicals increases your risk you'll have an adverse reaction.

Food allergies are the fifth leading cause of chronic illness in the U.S.,1 and the number of people who suffer from them is on the rise. In the decade between 1997 and 2007, the incidence of food allergies rose by nearly 18 percent in children under 18.2 Today, nearly 1 in every 13 children has some type of food allergy.3

Some of the more common foods that spark an allergic reaction in children are nuts, soy, wheat, shellfish and milk. Why those particular foods are the leading triggers is still not fully understood. Dr. Kari Nadeau, director for the Stanford Alliance for Food Allergy Research, points out there is no one protein similar between the foods, and that 30 percent of people who do have food allergies often are allergic to more than one food in that group.4

Scientists have found that allergies may run in families, meaning there may be a genetic factor, as well as environmental factors in the development of food allergies. However, at this point, there is no complete answer as to why some people develop a highly sensitive reaction to some foods and others don't. In the past, many of the cases of food allergies began in childhood, but today, it is not uncommon for those over 18 to develop an allergic reaction to foods, even those they have been eating their whole life.

Adult Onset Food Allergies Are Not Uncommon

Preliminary data from a national study shows that nearly 52 percent of Americans who have food allergies developed them after the age of 18.5 These same results showed that shellfish is the most common food allergy, followed by peanuts and then tree nuts, such as walnuts, pecans and cashews. Interestingly, when children are allergic to eggs, milk or wheat products, they may grow out of the reaction as they age. However, adults who develop a food allergy usually continue to suffer for the remainder of their life.

Dr. Ruchi Gupta, a food allergy researcher at Ann and Robert H. Lurie Children's Hospital, led this national study. She had found that in medical meetings around the world there appeared to be a higher number of adults reporting food allergies. However, as this was anecdotal evidence, Gupta and her team set out to quantify the information.6 The researchers surveyed over 40,000 adults from a national sample and found the foods that triggered allergic reactions in adults were the same as those affecting children.

Once the data was compiled, Gupta expressed interest in "why" adults develop food allergies. While gathering data from the sample, researchers asked the participants why they thought they had developed food allergies as an adult. The answers ranged from changing hormonal levels, moving to another area of the country or a viral illness.7 Gupta hopes to answer questions about why children maintain allergies through adulthood, and how adults are developing new ones, as these answers may have a significant public health impact.

The results of this study confirmed results of another study by FAIR Health that found a 377 percent jump in severe food reactions in the past decade.8 FAIR Health9 is a nonprofit, national repository of insurance claims data. The group looked through 24 billion insurance claims filed by 150 million people for diagnoses where anaphylaxis was caused by food reactions.

They discovered that not only had the number of individuals who experienced a severe food allergy jumped nearly fivefold from a decade ago, but nearly 25 percent of the claims were made in 2016.10 Another study by Food, Allergy, Research and Education (FARE), found that at least 15 percent of people who suffer from food allergies will develop them after age 18.11 Medical records of over 1,100 people diagnosed with food allergies were reviewed. The researchers found:12

  • The age of the first reaction peaked in the individual's 30s
  • The older the person at the time of the first reaction, the more severe the reaction
  • A higher percentage were female
  • Approximately 16 percent were allergic to more than one food

Do You Have a Food Allergy or Food Intolerance?

There is a difference between allergic food reactions and food intolerances. Although some of the symptoms may be similar, the differences are very important. If you are intolerant to a food, you may be miserable for hours to days after eating.13 However, if you are allergic, it could lead to a life-threatening situation. A food intolerance occurs in the digestive tract, while a food allergy triggers a systemic immune response.

The job of your immune system is to identify foreign invaders, separate them and destroy them. When your immune system overreacts to food or other allergens, it can result in a systemic allergic reaction. During an allergic reaction, your immune system mistakenly identifies specific a molecule as dangerous and produces immunoglobulin E (IgE) in an effort to neutralize the threat.14 Researchers suggest that childhood food allergies might be prevented with prenatal or early postnatal strategies toward desensitization.

Symptoms of a food allergy include hives, swelling, nausea and vomiting.15 If it progresses to cause life-threatening symptoms such as difficulty breathing or a drop in your blood pressure, it is called anaphylaxis. Some allergic reactions are less obvious, especially in children. Colic, reflux, eczema and chronic diarrhea may be signs of a food allergy in young children. One study found that up to 50 percent of cases of eczema in young children are the result of a food allergy.16

Symptoms of a food intolerance may be the result of an inability to digest the food from an enzyme deficiency or sensitivity to any of the food additives or chemicals. Sometimes, if you are intolerant, you may be able to eat small amounts of the food without experiencing a reaction. However, if you have a food allergy, you aren't able to eat any of the food without experiencing a reaction.17

A food intolerance does not involve the immune system and may be immediate or be triggered up to 20 hours after you've eaten the food. Symptoms of a food intolerance may be vague, such as bloating, passing gas, diarrhea or indigestion.  Another type of intolerance is called oral allergy syndrome, during which you may get tingling or swelling around your mouth after eating some fruits and vegetables.18

This reaction is common in 50 to 75 percent of people who are allergic to birch tree pollen as the proteins in some fruits and vegetables are the same as those in the birch tree. Oral allergy syndrome is a type of contact allergic reaction that usually appears immediately after eating the offending fruit or vegetable, does not usually lead to swelling of the throat and neck, and often disappears within hours.

Symptoms of Food Allergies May Not Be Obvious

In some instances, symptoms of a food allergy may not be as obvious as hives or swelling. For instance, an exercise-induced food allergy19 occurs when specific foods are eaten just before exercise, which may increase your potential for experiencing an allergic reaction, including serious or life-threatening reactions. Carefully track the foods you ate before the reaction and avoid them in the future. Not eating for two hours or more before exercise can help prevent this problem.

In many cases, gastrointestinal (GI) symptoms, such as bloating or gas, are related to a food intolerance. During a systemic immune response, histamine is released in your body. If the histamine is released to your skin, you develop hives that may progress to an anaphylactic response. However, if the histamine is released into your GI tract, it can cause nausea, diarrhea, vomiting and abdominal pain,20 in much the same way a food intolerance may present.

A rare food allergy to a protein in red meat may lead to GI symptoms, hives or anaphylactic shock.21 Many times, the allergic reaction is delayed by four to six hours, but not always. You may develop an allergic reaction to a protein molecule in red meat after being bitten by a Lone Star tick.22

In this case, something in the saliva of the tick prompts your body to create antibodies against galactose-alpha-1, 3-galactose carbohydrate molecule. Symptoms that develop after eating red meat include nausea, vomiting, stuffy nose, asthma or anaphylaxis. When you search medical studies in PubMed23 using the terms "food allergies" and "migraines" you are presented with over 150 studies associating migraine headaches with specific food allergies. Some of the top foods identified that induce migraines include:

Milk

Wheat

Yeast

Corn

Citrus

Cane sugar

Eggs

Grain cereals

The Number of Food Allergies Is on the Rise

Although the cause behind rising prevalence of adult-onset allergies is unknown, there may be several contributing factors. For example, there is a known association between food allergies and individuals with low levels of vitamin D.24 Since 75 percent of U.S. citizens are deficient in vitamin D,25 it makes sense the number of people suffering from food allergies is also rising.

In the past decade, food manufacturers have increased the number of additives, pesticides, herbicides and chemicals to packaged and whole foods, which also increases the number of potential allergens to which you are exposed at each meal. Genetic modification of foods may also increase the number of protein allergens found in plants, or create new ones.

Another common allergen that is added to many processed and packaged foods is soy. Although many Asian cultures eat soy each day in their diet, the soy they eat is fermented and quite unlike the soy fillers used in Western food. According to leading GMO expert, Jeffrey Smith:

"Levels of one known soy allergen, trypsin inhibitor, were up to seven times higher in cooked GM soy compared to cooked non-GM soy. Another study discovered a unique, unexpected protein in GM soy, likely to trigger allergies. In addition, of eight human subjects who had a skin-prick (allergy-type) reaction to GM soy, one did not also react to non-GM soy, suggesting that GM soy is uniquely dangerous.

… Documents made public from a lawsuit revealed that FDA scientists were uniformly concerned that GM foods might create hard-to-detect allergies, toxins, new diseases, and nutritional problems. Their urgent requests for required long-term feeding studies fell on deaf ears. The FDA doesn't require a single safety test."

Dr. Jonathan Hemler, pediatric allergy and immunology expert at Vanderbilt University School of Medicine, commented on the rising number of children and adults with food allergies, saying:26

"We have noticed that the prevalence of food allergy has tripled in the last 20 to 30 years. It's very concerning because we don't really have a good explanation as to why this is happening. Along with the increase in food allergy, we're also seeing more severe anaphylaxis events happening where adults have to go to the emergency room to get treatment."

Protection Begins in Your Gut

Protection against developing a food allergy may begin with your intestinal flora. Many of the pesticides in use today have an antibiotic action, including the dangerous, damaging and ever-present glyphosate. A steady diet of chemicals that have a low dose antibiotic action may have a devastating effect on your gut microbiome and trigger the development of food allergies.

Your gut microbiome plays an important role in your immune system and has an effect on your mood, cognitive function and overall health. One common bacteria found in your gut microbiome, Clostridia, may help protect against the development of food allergies. However, when your gut is affected by antibiotic action from your foods or prescribed medications, it may increase your risk of allergic reactions.

In a study using mice, researchers were able to demonstrate a lack of Clostridia in the mouse gut increased the probability the mouse developed food allergies,27 and when the Clostridia was returned, the food allergies subsided.28 When tested against Bacteroides, another bacterium found in the gut, it was only the Clostridia that had an effect against food allergies. The researchers discovered the Clostridia produced a signaling molecule called interleukin-22, known to help reduce the permeability of your gut wall.

This means the bacteria reduced the potential for leaky gut or the condition that allows allergens to enter your bloodstream. This discovery may lead to a formulation of probiotics specifically to treat food allergies and reduce leaky gut syndrome. Disruption of your gut microbiome may be the result of your food choices, past medication, cesarean birth, formula feeding or modern hygienic practices.

Truly, anyone suffering from food sensitivities or allergies would be wise to reconsider the kinds of foods they eat. Ultimately, your best bet is to switch to an all-organic diet. This is particularly important for young children and pregnant women, but I really believe this is the answer for everyone, whether you're prone to allergies or not.

Surviving a Systemic Allergic Reaction

Living with a food allergy may mean preparing to address anaphylactic shock if you unknowingly consume the wrong food. Although you may carry an auto-injector filled with epinephrine used to treat anaphylaxis, every reaction requires a trip to the Emergency Room.29 You may believe the epinephrine eliminated your symptoms, but you also have the risk of a rebound anaphylactic reaction once the effects of the epinephrine wear off. The injection is just part of the treatment as you may have more than one reaction.

If you or someone you're with appears to be having an anaphylactic reaction with symptoms of difficulty breathing, hives, swelling of the tongue or throat, change in voice quality or weak and rapid pulse,30 there are steps you can take to help increase the potential for survival:31

  • Immediately call your local emergency medical phone number; 911 in the U.S. Do not hesitate to call as emergency personnel would rather evaluate you and send you home than to find you have died at home.
  • If you or the person you are with is carrying an emergency epinephrine pen, use it immediately.
  • The person having the reaction should lie quietly until emergency personnel arrive.
  • Loosen tight clothing, cover with a blanket and lie on the left side, so aspiration of stomach contents into the lungs is prevented if vomiting occurs.
  • If the person you're with stops breathing and no longer responds, start CPR. Do uninterrupted chest compressions, approximately 100 per minute, until the paramedics arrive.
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