An allergic reaction is caused by a dysfunction in the immune system. Individuals may experience allergic reactions to foods, insect stings, latex, and a variety of environmental exposures. A food allergy reaction involves the immune system and occurs when a typically safe substance in foods, usually a protein, mistakenly triggers the body’s protective immune response. Reactions can range from mild to severe. The true prevalence of food allergies is not known.
The Centers for Disease Control and Prevention (CDC) reports that children with food allergies are more likely to have asthma or other allergic conditions. Nearly 90% of food allergies are caused by these common foods: tree nuts (almonds, walnuts, pecans, cashews, pistachios, etc.), peanuts, milk, eggs, fish, crustacean shellfish, wheat, and soy.
Fortunately, most allergic reactions are not life-threatening, but any food allergy reaction can be severe and unpredictable. Reactions can range from hives that quickly go away on their own to a reaction called anaphylaxis that may involve the respiratory and cardiovascular system and can be life-threatening. The only recommended treatment for anaphylaxis is epinephrine. For more information on treating a food allergy reaction, speak with your pediatrician or physician.
With increasing news coverage on peanut allergy in the past few years, there may be a misperception that there is a high incidence of peanut allergy in the U.S. and worldwide. However, the National Institute of Allergy and Infectious Disease (NIAID) estimates that only 0.6 – 1.0% of Americans have peanut allergy, and studies show that up to 20% of peanut allergies can be outgrown. Some studies estimate that as many as 2% of children may have a peanut allergy. However, the true prevalence of food allergies is unknown. Those with a family history of allergy, asthma, or eczema, may be at increased risk.
What Causes Peanut Allegery?
A peanut allergy occurs when a person’s immune system does not recognize peanut protein and mistakenly overreacts to it. Both genetic and environmental factors appear to be involved. The groundbreaking LEAP Study (2015) found that the introduction of peanuts into an infant’s diet, prior to 11-months old, reduced the prevalence of peanut allergy significantly. As a result of the LEAP study, new guidelines have been released to encourage early introduction of peanut foods. Research has shown that introducing peanut foods early to those infants who are at high risk reduced rates of developing peanut allergies by up to 86%. Implementing early introduction will hopefully reduce the prevalence of peanut allergies for future generations.
Family history, occurrence of eczema-type skin rashes, and exposure to soy protein were associated with the development of peanut allergy in childhood in one study, (18) but there is no clear cut answer as to why one child ends up with a peanut allergy and another does not. Both genetic and environmental factors seem to be involved.
Eating Peanuts During Pregnancy
For expectant mothers, limited evidence suggests that eating peanuts during pregnancy may help to reduce the risk of a peanut allergy in the child. The Growing Up Today Study (GUTS) examined 10,907 children whose mothers provided dietary information while they were pregnant and within one year of pregnancy. Peanut allergies were significantly lower in the children of 8059 nonallergic mothers who consumed more peanuts than those who did not. More evidence is needed in this area. Maternal peanut consumption during pregnancy or lactation had no effect on developing allergy in one study, (20) nor did duration of breastfeeding. (18)
The Risk of Casual Contact
In those who are especially sensitive, reactions to peanuts can occur from ingesting just a trace amount. This can cause anxiety, especially for the parents of peanut-allergic children. However, research shows that touching, smelling, inhaling airborne particles or just being near peanuts is highly unlikely to cause a severe reaction (Simonte SJ, et al. Relevance of casual contact with peanut butter in children with peanut allergy. J Allergy Clin Immunol. 2003 Jul:112 (1): 180-2.)
Smelling the aroma of peanuts is not the same as inhaling airborne peanut particles that could potentially contain the allergenic protein. The aroma of peanuts comes from different compounds that cannot cause an allergic reaction. Also, highly refined peanut oil is not required to carry allergen labeling because the process used to purify the oil removes the protein, thereby making it no longer allergenic.
In one controlled study, 30 children with significant peanut allergy were exposed to peanut butter, which was either pressed on the skin for one minute, or the aroma was inhaled. Reddening or flaring of the skin occurred in about one-third of the children, but none of the children in the study experienced a systemic reaction.
To prevent an allergic reaction it is essential to avoid eating the allergenic food. Here are some tips to minimize the risk of being exposed to allergens:
- Read labels every time, even if the food has been eaten safely in the past, since manufacturers can change their formulations. Look for a “contains” statement and read the ingredient list, since manufacturers can list allergens in either place.
- Plan ahead when dining out or attending a party. Call ahead to talk with restaurant staff, or use a “chef card,” which lists ingredients to avoid and can be found at the Food Allergy Research & Education (FARE) website at https://www.foodallergy.org/sites/default/files/migrated-files/file/chef-card-template.pdf.
- Keep surfaces clean by using common household cleaning agents that have been proven to remove proteins after potential allergens have touched them.
- Carry medicine such as epinephrine auto-injector pens. Epinephrine is life-saving medication that should be used any time anaphylaxis is suspected. Always call 911 after using epinephrine to treat anaphylaxis as a second reaction may occur and additional medical care could be needed.
- Control asthma with proper medical care, since asthma is a significant risk factor for death due to anaphylaxis.
- Let people know about your allergy by wearing an emergency alert bracelet or necklace identifying the allergy and its severity.
Foodservice professionals should also take special care to minimize the risk of exposure to food allergens for food allergic individuals. Some strategies for reducing exposure to food allergens in the foodservice setting include:
- Training staff on handing foods that can cause allergy
- Sanitizing equipment and workspaces to avoid cross contamination during food preparation
- Posting signs in appropriate areas when foods with allergens are served
- Properly labeling any in-house packaged foods that contain allergens
- Having a plan for readily accessing emergency medical care.
Food Allergen Bans
Evidence does not support the effectiveness of food allergen bans. In fact, many experts feel that food bans, except in situations that involve very young children such as in daycare centers, give a false sense of security. Peanut bans, for example, ignore other potentially serious food allergies. School-aged children need to be prepared to understand real-world environments. An approach that includes preparedness and training of faculty, school food service personnel, parents and students on how to manage food allergies is thought to be the most effective approach.
A number of therapeutic interventions to treat peanut allergy are currently being studied. Among these are an oral immunotherapy (OIT) study for desensitization (including the PALISADE trial) which was published in the New England Journal of Medicine November 18, 2018. Oral immunotherapy induces the body’s immune system to tolerate a food that it is currently overreacting to. This is done by consuming extremely small quantities of the allergen on a regular basis, in gradually increasing amounts. Previous randomized, controlled clinical trials have provided evidence that daily peanut OIT can reduce the severity of allergic reactions to peanut.23-25. Over 77% of participants in the study were able to tolerate 300mg of peanut protein which resulted in a significant increase in tolerance.
Epicutaneous Immunotherapy (EPIT) sometimes referred to as the “patch” has shown itself to be safe and effective in peanut allergic participants. At this time, these treatments are considered investigational.
What Causes Peanut Allergy?
The science is not clear as to what causes peanut allergy. Both genetic and environmental factors appear to be involved. The groundbreaking LEAP Study (2015) found that the introduction of peanuts into an infant’s diet, prior to 11-months old, reduced the prevalence of peanut allergy significantly. As a result of the LEAP study, new guidelines have been released to encourage early introduction of peanut foods. Research has shown that introducing peanut foods early to those infants who are at high risk reduced rates of developing peanut allergies by up to 86%. Implementing early introduction will hopefully reduce the prevalence of peanut allergies for future generations.
The FDA is currently testing a unique Chinese herbal formula called “Food Allergy Herbal Formula-2,” which may prevent anaphylactic reactions following the treatment. (9) “Anti-IgE therapy” is showing promise, which increases the threshold of sensitivity to peanut allergens. (10) Also, the blocking of different hormones involved in anaphylaxis is currently being tested in mice. (11)
9. Srivastava KD, et al. Food Allergy Herbal Formula-2 silences peanut-induced anaphylaxis for a prolonged posttreatment period via IFN-gammaproducing CD8+ T cells. J Allergy Clin Immunol. 2009 Feb;123(2):443-51.
10. Jones SM, Scurlock AM, Pons L, et al. Doubleblind placebo-controlled (DBP) trial of oral immunotherapy in peanut allergic children. J Allergy Clin Immunol. 2009;123:S211.
11. Varshney P, Jones SM, Pons L, et al. Oral Immunotherapy (OIT) Induces Clinical Tolerance in Peanut-Allergic Children. J Allergy Clin Immunol. 2009;123:S174.
18. LEAP – Learning Early About Peanut Allergy. Available at: www.leapstudy.co.uk Accessed April 6, 2009.
19. Lack G, et al. Factors associated with the development of peanut allergy in childhood. N Engl J Med. 2003 Mar 13;348(11):977-85.
20. Fox AT, et al. Household peanut consumption as a risk factor for the development of peanut allergy. J Allergy Clin Immunol. 2009 Feb;123(2):417-23.
21. Du Toit G, et al. Early consumption of peanuts in infancy is associated with a low prevalence of peanut allergy. J Allergy Clin Immunol. 2008 Nov;122(5):984-91.
22. Greer FR, et al. American Academy of Pediatrics Committee on Nutrition; American Academy of Pediatrics Section on Allergy and Immunology. Effects of early nutritional interventions on the development of atopic disease in infants and children: the role of maternal dietary restriction, breastfeeding, timing of introduction of complementary foods, and hydrolyzed formulas. Pediatrics. 2008 Jan;121(1):183-91. Review.
23. Anagnostou K, Islam S, King Y, et al. Assessing the efficacy of oral immunotherapy for the desensitisation of peanut allergy in children (STOP II): a phase 2 randomised controlled trial. The Lancet 2014;383(9925):1297-304.
24Tang ML, Ponsonby AL, Orsini F, et al. Administration of a probiotic with peanut oral immunotherapy: A randomized trial. J Allergy Clin Immunol 2015;135(3):737-44 e8.
25Vickery BP, Scurlock AM, Kulis M, et al. Sustained unresponsiveness to peanut in subjects who have completed peanut oral immunotherapy. J Allergy Clin Immunol
26 Jarvinen KM, Westfall J, De Jesus M, et al. Role of Maternal Dietary Peanut Exposure in Development of Food Allergy and Oral Tolerance. PLoS One 2015;10(12):e0143855.
27 Frazier AL, Camargo CA, Jr., Malspeis S, Willett WC, Young MC. Prospective study of peripregnancy consumption of peanuts or tree nuts by mothers and the risk of peanut or tree nut allergy in their offspring. JAMA Pediatr 2014;168(2):156-62.
Is Peanut Oil Allergenic?
Since peanut oil is pressed from peanuts, some have questioned if peanut allergic individuals will react to peanut oil. This question has confused many who would like to enjoy a Sichuan stir-fry, deep-fried turkey, or other foods cooked in peanut oil.
The fact is that highly refined peanut oil is different from peanuts, peanut butter, and peanut flour when it comes to allergy. This is because highly refined peanut oil undergoes a process, in which it is purified, refined, bleached, and deodorized. When highly refined, the proteins in the oil that can cause allergic reaction are removed. The vast majority of peanut oil used in foodservice and by consumers in the U.S. is processed and is considered highly refined. Gourmet peanut oil (unrefined) does contain peanut protein and is not considered safe for those with peanut allergies.
The FDA Food Allergen Labeling and Consumer Protection Act of 2004 and the Federal Food, Drug, and Cosmetic Act (FFDCA) indicate that highly refined oils are not major food allergens.
The Federal Food, Drug, and Cosmetic Act states:
“(qq) The term `major food allergen’ means any of the following:
- Milk, egg, fish (e.g., bass, flounder, or cod), Crustacean shellfish (e.g., crab, lobster, or shrimp), tree nuts (e.g., almonds, pecans, or walnuts), wheat, peanuts, and soybeans.
- A food ingredient that contains protein derived from a food specified in paragraph (1), except the following:
- Any highly refined oil derived from a food specified in paragraph (1) and any ingredient derived from such highly refined oil.
- A food ingredient that is exempt under paragraph (6) or (7) of section 403(w).”
Unrefined, “gourmet,” “aromatic,” or cold-pressed oils may still contain proteins that cause allergy. They can also be referred to as “crude” oils. The use of these specialty oils is limited; however, it should be recognized that not all available peanut oil is highly refined. If an allergic individual is unsure as to whether a product contains or was fried in highly refined peanut oil, that individual should ask the manufacturer or restaurant for clarification.
According to Food Allergy Research & Education (FARE), “Highly refined peanut oil is not required to be labeled as an allergen. Studies show that most people with peanut allergy can safely eat this kind of peanut oil. If you are allergic to peanuts, ask your doctor whether you should avoid peanut oil.
But avoid cold-pressed, expelled or extruded peanut oil—sometimes called gourmet oils. These ingredients are different and are not safe to eat if you have a peanut allergy.”
How many people have food allergies?
- It may seem like more, but only 4% of adults and 4% of children have food allergies.
- About 90% of food allergies are caused by tree nuts (almonds, walnuts, pecans, cashews, pistachios, etc.), peanuts, milk, eggs, fish, shellfish, wheat, and soy.
What about peanut allergies?
- About 0.6 – 1.0 % of people have peanut allergy, which can vary from mild to severe.
- Nearly 20% of peanut allergies can be outgrown.
- Four times as many people are allergic to seafood than to peanuts.
It seems like more people have peanut allergies, why?
- The prevalence of peanut allergy doubled from 1997 to 2002.
- This increase may be a result of better reporting and improved detection of allergies, which should be diagnosed by a physician.
- The reported increase in peanut allergy mirrors an overall increase in childhood allergies.
Are all peanut allergies severe?
- No, some are mild; however, in those who have severe reactions, ingesting just a trace amount can cause a reaction.
- It is critical to manage peanut allergies, as with any allergy, to avoid severe reactions, such as anaphylaxis.
What is the allergen in peanuts?
- The major proteins Ara h 1, Ara h 2, and Ara h 3 are the allergens in peanuts.
- Smelling the aroma of peanuts cannot cause an allergic reaction.
What about peanut oil?
- Highly refined peanut oil is different from peanuts and from “crude” or gourmet peanut oil because it does not contain peanut allergens.
- Highly refined peanut oil is purified, refined, bleached, and deodorized, which removes the allergic proteins from the oil.
- The majority of peanut oil used by foodservice has been highly refined and processed.
- The FDA does not consider highly refined peanut oil a food allergen.
See more by downloading the fact sheet on peanut allergy.
Or, to download the full White Paper on Peanut Allergy.
For the latest research and information on managing peanut allergies, please visit peanutallergyfacts.org.