• Originally published August 24, 2010 at midnight, updated August 24, 2010 at midnight

With the frequent outbreaks of tainted food – from produce to pantry staples like peanut butter – Americans are paying more attention than ever to what they eat. For the several million Americans living with food intolerances and allergies, carefully reading food labels and monitoring reactions to certain foods is an everyday routine.

FOOD INTOLERANCE
A food intolerance is different from a true food allergy because it does not involve the immune system. Food intolerance is an abnormal reaction – such as abdominal pain or gas after consuming milk – after eating a certain food. Common symptoms of food intolerance include:

Bloating and heartburn

Possibly severe nausea, headaches or vomiting

FOOD ALLERGY
Food allergies affect an estimated six to seven million Americans and are becoming increasingly common among both children and adults. the effects are often underestimated: a food allergy can cause serious health problems and even death. What’s more, a recent report from the Centers for Disease Control suggests that food allergies are becoming more prevalent. An October 2008 CDC study found that child food allergies alone are up 18 percent over the last decade. some of these allergies can be outgrown in time, but others last into adulthood.

A food allergy is much more serious than a food intolerance. In the case of a food allergy, the body’s immune system will perceive an ordinary food as a contaminant, and the immune system will release antibodies to fight the foreign agent.

Eight types of foods are responsible for 90 percent of food allergies, according to the CDC: milk, eggs, peanuts, tree nuts, fish, shellfish, soy and wheat.

Symptoms can appear after exposure to only a trace amount of the allergen and can range from mild to severe. Symptoms may include:

Hives – red, swollen, itchy bumps on the skin that appear suddenly

a red, itchy rash on the skin

a stuffy or itchy nose or eyes, congestion or sneezing

Gas, stomach or abdominal cramps, vomiting or diarrhea.

A severe allergic reaction, called anaphylaxis, can involve any of the above symptoms, as well as a feeling of lightheadedness, anxiety, throat tightness, coughing or breathing difficulties – and, if not treated promptly, can lead to death. Immediate medical attention is imperative for a severe allergic reaction – even if the symptoms subside.

Food allergies are often inherited and are most often diagnosed by your family history, according to the American Academy of Allergy, Asthma and Immunology, rather than a skin or blood test alone. a food allergy can also raise your risk of other allergies, such as asthma, according to recent industry studies, so it’s important to see your doctor if an allergy is suspected.

Susan Sizemore is a registered and licensed dietitian. Send questions or comments to .