Food allergies occur when the immune system overreacts to certain proteins in food. True food allergies affect as many as seven percent of children and about two percent of adults, says S. Allan Bock of the National Jewish Medical and Research Center in Denver.
Although more than 200 food ingredients can provoke an allergic reaction, the vast majority are caused by the big eight: nuts (like walnuts and almonds), peanuts (theyre legumes, not nuts), milk, eggs, fish, shellfish, soybeans, and wheat. Typical symptoms are nausea, hives, skin rash, nasal congestion, and wheezing.
Most kids outgrow their allergies by the time they reach adolescence, but some allergiesparticularly to peanuts, nuts, and seafoodrarely go away. They require lifelong vigilance, says Hugh Sampson of the Jaffe Food Allergy Institute at the Mount Sinai School of Medicine in New York. And anyone can develop new allergies at any time.
For most sufferers, allergic reactions to food are a temporary discomfort. But not for the estimated 30,000 people each year in the U.S. who eat the wrong food and go into anaphylactic shock, a swift and terrifying reaction in which their throats can swell enough to cut off breathing. About 150 of them die, despite the efforts of rescue squads and hospital emergency rooms:
In 1991, 12-year-old Umar Murtaza died in a Los Angeles hospital several hours after eating a piece of birthday cake that contained crushed pecans. He was allergic to nuts.
In 1998, 12-year-old Kristine Kastner, who was allergic to peanuts, took one bite of a neighbors homemade chocolate-chip cookie. Her mother had checked the cookie, but didnt notice the finely chopped peanuts. Kristines throat and tongue immediately began to swell and she started to wheeze and struggle for breath. The ambulance that responded didnt carry emergency epinephrine (adrenaline), which might have saved Kristines life. She died in a Seattle-area hospital 45 minutes later.
In 1999, the day after hosting a cookout for his championship lacrosse team, 18-year-old Joe Murphy ate some pistachio nuts. The Boston-area resident knew he was allergic to peanuts but had no idea that he couldnt eat pistachios either. Murphy collapsed into anaphylactic shock, then fell into a coma. He died nine days later.
According to a new study of 32 people who died following an allergic reaction, fatal anaphylactic shock follows a clear pattern.1 All but two reactions were triggered by peanuts or nuts. Most of the victims were teenagers or young adults who had asthma, and most knew that they suffered from food allergies. Twenty-seven ate the food away from home. And only three were carrying emergency self-injectable epinephrine.
Perhaps the most disturbing finding is that early administration of epinephrine may not always be life-saving, says co-author Hugh Sampson. Four patients succumbed to a fatal reaction despite receiving epinephrine in a timely fashion.
That, says Sampson, emphasizes the need for good education and good labeling. If treatment doesnt work, prevention becomes more critical.
And even if epinephrine does work, victims cant depend on medics to have it. Many states permit only paramedicsnot the emergency medical technicians who staff many ambulancesto carry epinephrine to treat anaphylactic shock.
Despite the serious consequences of peanut allergies, only about half of the adults in the U.S. who have experienced serious allergy-like symptoms after eating peanuts have seen a physician about it.2 And just seven percent kept emergency epinephrine handy.
Most reactions to food are caused not by allergies but by intolerances, which are less severe (except for those caused by sulfites). Intolerances could be triggered by most any food, which makes them harder to pin down. Here are the intolerances youre most likely to experience:
Lactose. Its the most common intolerance. An estimated three out of every ten Americans adultsparticularly people of African, Asian, or Mediterranean heritagedont produce enough of the enzyme lactase to digest all the lactose (milk sugar) they consume. When too much undigested lactose reaches the large intestine, it can cause gas or diarrhea.
But people with lactose intolerance dont have to avoid all dairy products. Somelike cheese, ice cream, and yogurthave much less lactose than milk does. And most lactose-intolerant people dont even have to give up milk.
Our studies show that people who believe they are lactose intolerant can still consume the equivalent of a cup of milk in the morning and another one in the evening with little or no discomfort, says Michael Levitt, a gastroenterologist at the VA Medical Center in Minneapolis.3
Sulfites. These sulfur-containing additives are used as preservatives in dried fruits, wines, and dehydrated potato products like mashed potato flakes.
About one in every 100 people with asthmasome 100,000 Americansare sensitive to sulfites, says allergy expert Steve Taylor of the University of Nebraska in Lincoln. If they eat a food that contains sulfites, their throats may constrict and cut off the flow of air. Sulfite sensitivity can develop at any age.
From 1980 to 1999, the FDA received 1,132 reports of badand in at least a dozen cases fatalreactions to sulfites. More than 90 percent of them occurred in restaurants or other places outside the home. But the number of reported reactions has averaged only about ten a year since 1996, and no deaths have been recorded since 1990. That steep decline was no accident. Starting in 1982, the Center for Science in the Public Interest (CSPI), publisher of Nutrition Action Healthletter, waged a four-year campaign to get the FDA to ban sulfites from food.
In 1986, the Feds met CSPI half way. The FDA required labels to list sulfites if a food contains at least ten parts per million (thats the lowest concentration that can be reliably detected). It also prohibited restaurants, supermarkets, and food processors from using sulfites on fruits and vegetables (except grapes) that are sold raw or likely to be eaten raw. That got sulfites out of the hands of restaurant chefs, who may have been using too much on the salad-bar ingredients.
But the FDA has yet to act on CSPIs request to require restaurants to disclose which of their foods contain sulfites.
If youre sulfite-sensitive, avoid foods that contain sulfur dioxide, sodium sulfite, sodium or potassium bisulfite, or sodium or potassium metabisulfite.
Monosodium Glutamate (MSG). This flavor-enhancer has been blamed for Chinese Restaurant Syndrome, the headaches and flushing some people report after eating Chinese food, which is often prepared using MSG. But linking MSG to symptoms has been difficult.
Researchers at Harvard University tested 130 people who believed they were sensitive to MSG.4 In two separate tests, 19 of them reacted to five grams of MSG (an enormous dose), but not to a look-alike (but MSG-free) placebo. Twelve agreed to be retested. Only two of the 12 reacted to the large dose of MSG but not the placebo in the retest.
Our research confirms that some people are sensitive to MSG, but its not common and the symptoms are extremely mild, says Harvard researcher Raif Salim Geha.
The FDA requires food manufacturers who use MSG to list it on their labels as monosodium glutamate. In 1993, the FDA proposed that companies put contains glutamate on the labels of foods made with hydrolyzed vegetable protein or other sources of glutamate (to which sensitive people say they also react). But it never followed through on its proposal.
Red wine. Some people report getting headaches after drinking redbut not whitewine. The culprit probably isnt the alcohol or the sulfites, but the phenolic flavonoids that are found in grape skins (red wine has more than white). Those same flavonoids may cut the risk of heart disease (but the evidence is sketchy).
Chocolate. Many of the ingredients used in making chocolate candyincluding milk, nuts, soybeans, corn syrup, and chocolate itselfcould be responsible for the headaches that some people report after eating chocolate. (No research comparable to the Harvard MSG study has ever tested peoples reactions to chocolate.)
Food Colors. Some people react with itching or hives to a synthetic yellow food coloring called tartrazine, or Yellow No. 5. Thats why the FDA requires manufacturers who use Yellow No. 5 to list it on their labels.
Synthetic food colors can also provoke behavior problems like irritability and restlessness in susceptible children (see Diet and Behavior in Children, March 2000).
It isnt always easy to avoid foods that trigger allergic or intolerance reactions.
1) Offenders may show up where you dont expect them. Milk, soy, wheat, nuts, and eggs are staples of the food industry. Progresso Chicken Noodle Soup? Its made with soy, egg whites, and MSG. Thomas English Muffins? Its got soy, milk, and whey. And youll find wheat, soy, sulfites, and MSG in Rice-A-Roni Spanish Rice.
Restaurant foods are even trickier because chefs and waiters may not know what ingredients were added to the broths, sauces, breadings, and other prepared foods they cook with.
2) Trace amounts can trigger a reaction. People who are exquisitely sensitive to certain foods report that just being in the same room as the food can trigger an allergic reaction. Clearly, it doesnt take much. For example, a 14-year-old girl who was allergic to peanuts died during a camping trip after eating a sandwich. It had been made using a knife that had been used earlier to make a peanut-butter-and-jelly sandwich.1
In a recent study, researchers gave 14 peanut-allergic volunteers small doses of ground-up peanuts on some days and look-alike (but peanut-free) placebos on other days. As little as one ten-thousandth of a teaspoon of peanut protein provoked mild symptoms in two of the 14.5
3) Foods can be contaminated with allergens. In a disturbing new unpublished FDA study, inspectors found that only half of 85 randomly selected candy, ice cream, and baked-goods plants in Minnesota and Wisconsin were checking to see that the ingredients listed on their labels matched the ingredients in their foods.
Even more shocking: Half of the plants that didnt check were turning out foods that contained allergens not disclosed on the labels. Many used the same utensils to make foods with peanuts or eggs and foods that were supposed to be allergen-free.
Inspectors analyzed 118 samples of foods that they suspected of having undeclared allergens. One in ten samples contained egg allergens...and one in four contained peanut allergens.
In all, about 25 percent of the firms had some products that were coming off the line with undeclared allergens in them, says the FDAs Kenneth Falci. The goal should be that no foods come off the line that way.
No wonder people with severe allergies have to worry about packaged foods.
In 1997, a three-year-old boy in Bristol, Tennessee, who was allergic to milk ate half a cup of lemon sorbet. Within 20 minutes, his face started to swell and he began to vomit. It turned out that the sorbet contained tiny amounts of milk and whey protein, which didnt appear on the label. Those ingredients had been in the ice cream made during the previous four months using the same equipment.6
Last fall, Ben & Jerrys recalled 80,000 pints of its Peanut Butter Cup ice cream after realizing that the company had accidentally added nuts to it. Six consumers reported suffering allergic reactions.
In a case I was involved with, recalls Hugh Sampson, a college student who was allergic to peanuts bought cookies from a vending machine. They did not have peanuts listed on the label. But there were peanuts in the cookies, and the student died after eating them. Apparently, the company had a little bit of batter left over from some peanut butter cookies and just threw it into a batch of another kind of cookie and figured that it didnt matter.
U.S. food manufacturers were forced to recall 125 products last year because they contained undeclared allergens.
4) Labels dont have to disclose allergens in flavors. When a food contains flavorings that are derived from plants or animals, the ingredient list can simply say natural flavor. Sounds innocent, but those flavorings could contain allergens from milk, eggs, nuts, or other foods.
In 1996, the FDA asked the food industry to voluntarily label the sources of flavors if they contained known allergens, says Peter Skinner, a scientist in the New York State Attorney Generals Office. Some firms have more or less complied, but a lot of others havent or are doing it in their own unique way, so there is no real consistency across the board.
Last year, tired of waiting for the FDA to close up this loophole, the Attorneys General of New York and eight other states, including Michigan, Ohio, and Tennessee, petitioned the FDA to change the law (see Making Food Safe).
Genetic engineering may one day make the plants and animals we eat more nutritious and abundant. And it has the potential to eliminate allergens from soybeans, nuts, and other foods (as well as the caffeine from coffee beans).
But it also could introduce allergens into foods where none existed before, though the odds of that happening are probably small. Thats because companies are supposed to test whether their genetically engineered foods contain any new proteins that behave like allergens. There are certain criteria that we look atsuch as heat stability, enzyme stability, and whether its related to a known allergenthat tell us if a protein is likely to provoke an allergic reaction, says Mount Sinais Hugh Sampson. That process, if carried out carefully, should exclude almost all allergens, though nobody can say for sure that a new protein wont be a problem.
Several years ago, the Environmental Protection Agency (EPA) determined that a genetically engineered corn called StarLink contained a protein with properties similar to those of many allergens, so it approved the corn for use in animal feed only.
Yet, despite promises from the manufacturer that StarLink would never show up in human food, last summer it turned up in dozens of yellow-corn products, including taco shells and chips. (The manufacturers quickly removed the foods from store shelves.) Approving a food for animal but not human use will probably never happen again, says Sampson.
To guard against allergens and other potential problems, the Center for Science in the Public Interest (publisher of Nutrition Action Healthletter) wants all genetically engineered foods to be approved by the Food and Drug Administration (FDA) before they are marketed. In addition, the FDA should not allow genes for known allergens to be engineered into new foods.
About 150 people a year in the United States die from anaphylactic shock caused by a food allergy.
Since there is no treatment or cure for food allergies, the only way to avoid an allergic reaction is to avoid the offending food.
Allergies to peanuts, nuts, and seafood seldom disappear with age.
If someones mouth and throat start to swell, making breathing difficult, call for emergency medical help to take the person to a hospital.
If you have a severe allergy, always carry self-injectable epinephrine...and use it at the first hint of a strong reaction. Ask your doctor for a prescription.
Most food intolerances have been poorly studied. And except for those caused by sulfites, most are not serious.
In May 2000, the Attorneys General of Connecticut, Maryland, Massachusetts, Michigan, New York, Ohio, Tennessee, Vermont, and Wyoming asked the Food and Drug Administration to make it easier for consumers to identify and avoid foods that can trigger allergic reactions.
You can help support their sensible proposal by mailing this coupon (Acrobat 266k) or sending an email.