Food allergies occur when the immune system overreacts to certain proteins in food. 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 (they’re 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 allergies—particularly to peanuts, nuts, and seafood—rarely go away. And anyone can develop new allergies at any time.
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. The most common intolerances are:
Lactose. An estimated three out of every ten Americans adults— particularly people of African, Asian, or Mediterranean heritage— don’t 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.
Sulfites. These sulfur-containing additives (including sulfur dioxide, sodium sulfite, sodium or potassium bisulfite, and sodium or potassium metabisulfite) are used as preservatives in dried fruits, wines, and dehydrated potato products like mashed potato flakes. Before 1990, sulfites were often present in large amounts—and killed people. Since then, the government has banned sulfites from fresh produce and limited the amounts in other foods. That appears to have solved the problem.
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.
Red wine. Some people report getting headaches after drinking red—but not white—wine. The culprit probably isn’t the alcohol or the sulfites, but rather 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 candy—including milk, nuts, soybeans, corn syrup, and chocolate itself—could be responsible for the headaches that some people report after eating chocolate.
Other relevant links:
- Follow these food safety tips to keep your family healthy. See: Food Safety Tips for Packing and Unpacking Your Food
- Consumers need easy-to-comprehend information on the front of food packages. See: FDA Should Revamp Nutrition Labels
- How can you lower your odds of getting food poisoning from resistant bacteria? See: Food Poisoning from Antibiotic-Resistant Bacteria